Telehematopathology in a clinical consultative practice

We studied a series of 60 telepathology cases sent in consultation to the Department of Hematopathology from January 1, 1995, through July 31, 2000. Cases from the United States and the world representing academic, private, military, and federal sectors were reviewed. Ninety percent of patients were adults (54 of 60), and male patients outnumbered female patients 2 to 1. Ages were from 1 to 79 years (mean, 42 years). Forty-three cases were lymph nodes (72%), 14 were bone marrow or peripheral blood (23%), and 3 were from other sites (5%). Twenty-seven of the consultant diagnoses were benign (27 of 60). Twenty-nine were malignant (non-Hodgkin lymphoma, Hodgkin disease, and "other malignancy" groups), and 4 were nondiagnostic. Glass slide/paraffin tissue blocks were available in only 35 (58%) of 60 cases. The concordance rate for diagnostic telehematopathology cases with subsequent glass slide/paraffin block follow-up was 91% (29 of 32 cases). The discordance rate was 9% (3 of 32). This finding shows a high degree of diagnostic accuracy for consultative telehematopathology. Of 118 images analyzed, 58 were considered very good/good (49%), 32 were poor/very poor (27%), and 28 were fair (24%). Poor images had suboptimal resolution, color, or technical quality of transmission, and most poor images were low-power images. Additional case problems included insufficient immunoperoxidase stain availability, selection, and labeling; transmitted field selection; specimen preparation and staining; presence or absence of accompanying clinical data; and availability of ancillary studies such as flow cytometric, cytogenetic, and molecular data. From this analysis, the following recommendations are offered. To optimize telehematopathology consultation, include any additional information that have a significant influence on the final consultant diagnosis. Include any pertinent clinical information, laboratory data, special stains, immunoperoxidase stains, and molecular data. Select representative and diagnostically significant low-power and high-power fields for an accurate diagnosis. Label every immunostain or special stain submitted. Always send glass slides and tissue blocks when requested by the consultant. Optimize telemedicine microscopy and computer equipment with appropriate technical expertise, training, and support. In conclusion, the field of telepathology offers an exciting and potentially powerful solution to the problem of national and global subspecialty consultation. Hematopathology is potentially well suited to this technologically advanced marriage of computer and Internet technologies with modern microscopy, molecular diagnostics, immunophenotypic profiling, and the consultant pathologist.

c-Kit (CD117) reactivity in extramedullary myeloid tumor/granulocytic sarcoma

CONTEXT

c-kit, a proto-oncogene, encodes the transmembrane tyrosine kinase receptor CD117 and is detected by flow cytometry in the majority of cases of acute myeloid leukemia. The prognostic significance of the presence of c-Kit in acute myeloid leukemia is debated. Recently, c-kit inhibitors have been studied as possible therapies against hematopoietic malignancies; therefore, c-Kit detection may have important implications for treatment.

OBJECTIVES

In this study, we investigated the expression of c-Kit in granulocytic sarcoma (GS) using paraffin-embedded tissue.

DESIGN

Routinely formalin-fixed, paraffin-embedded tissues from 30 cases of GS were studied using immunohistochemistry. c-Kit (C-19) (a polyclonal antibody against carboxy terminal domain of c-Kit p145 or CD117) reactivity was compared with myeloperoxidase and lysozyme. The immunohistochemical panel also included CD34, CD68, CD43, Bcl-2, CD45RB, CD20, CD3, CD10, terminal deoxynucleotidyl transferase (TdT), and CD79a.

RESULTS

The morphologic patterns included well-differentiated (5 cases), poorly differentiated (19 cases), and blastic forms (6 cases). Clinical data were obtained from 28 of 30 patients. Granulocytic sarcoma presented in lymph nodes in 10 cases, whereas in 20 cases it presented in extranodal sites. c-Kit reactivity was found in 87% (26/30) of the GS cases. There was no significant difference in c-Kit positivity between the nodal (90%, 9/10) and extranodal (85%, 17/20) neoplasms. c-Kit expression was not associated with the degree of the myeloid maturation. Two of 13 lymphoblastic lymphoma control cases and 1 of 28 of the large B-cell lymphomas were weakly immunoreactive with c-Kit.

CONCLUSIONS

c-Kit reactivity can be demonstrated in a high percentage of GS cases; its presence may be useful not only in diagnosis, but also in the treatment of GS with new modalities.

Cutaneous follicle center lymphoma: a clinicopathologic study of 19 cases

Cutaneous follicle center lymphoma (FCL) is reported to have a unique immunophenotype and clinical course as compared with nodal FCL. We studied 19 cases of FCL of the skin using paraffin embedded tissue. An immunohistochemistry panel included CD45, CD3, CD20, CD43, CD21, bcl-2, bcl-6, CD5, and CD10. Molecular studies were performed by polymerase chain reaction for immunoglobulin heavy chain (IgH) and t(14;18). Trisomy 3 was performed by fluorescent in situ hybridization (FISH) in 13 cases. Follow up was obtained in 17 cases (range 3 to 137 months). Patients included 10 females and 9 males ranging in age from 33 to 88 years at first presentation (mean, 64). Twelve of 19 presented in the head and neck and 6 in the trunk and 1 on the arm. All had no known lymph node disease at presentation. Seventeen patients had no nodal disease with a minimum 3 month follow-up; 2/19 had unknown lymph node status with no follow-up. All cases were immunoreactive with CD20 and negative with CD3. Bcl-2 was immunoreactive in 11/18 cases, bcl-6 in 15/15, CD10 in 14/17, CD43 in 2/16 (both were CD10 immunoreactive) and CD5 in 1/15 (it was also bcl-6 immunoreactive). Eight of 18 cases were monoclonal for IgH. Three of 17 showed the presence of t(14;18). FISH was positive in 4 cases for trisomy 3 ranging from 16 to 22% (12% threshold). Follow-up showed no evidence of disease in 14/17 patients (4 to 137 mos). 3/17 patients are alive with disease (17 to 100 mo), and no patients died of disease.

Extranodal marginal-zone B-cell lymphoma of the salivary gland

Primary non-Hodgkin's lymphoma of the salivary gland is an uncommon tumor that most often occurs in the parotid gland. The most common subtype is marginal-zone B-cell lymphoma, extranodal, mucosa-associated lymphoid tissue type. This subtype has recently been included in the Revised European-American Classification of Lymphoid Neoplasms, as well as in the upcoming World Health Organization classification of hematopoietic and lymphoid neoplasms. This low-grade lymphoma usually arises in a background of benign lymphoepithelial lesion or myoepithelial sialadenitis that is associated with the autoimmune disease Sjögren's syndrome. It occasionally develops in patients who do not have a history of autoimmune disease. When mucosa-associated lymphoid tissue lymphoma occurs in the salivary gland, as in other extranodal sites such as the stomach, it is usually an indolent neoplasm that tends to remain localized for long periods of time, even without treatment. Eventually, however, the tumor may disseminate or transform to a higher grade. The histologic distinction of myoepithelial sialadenitis from low-grade B-cell mucosa-associated lymphoid tissue lymphoma can be a difficult diagnostic challenge and many of these lesions continue to be ambiguously diagnosed as "pseudolymphoma." Immunophenotypic or flow cytometric analysis may be useful in showing an aberrant phenotype or immunoglobulin light-chain restriction, which helps to support a diagnosis of malignant lymphoma in most cases. Molecular genetic analysis for immunoglobulin gene rearrangements also may be useful in showing monoclonality, although the exact significance of this finding in some cases remains controversial.

Low-grade B-cell lymphoma with coexpression of both CD5 and CD10. A report of 3 cases

The coexpression of CD5 and CD10 has previously been reported in cases of intermediate- and high-grade lymphomas and in precursor B cells in normal or regenerating bone marrow. We report 3 cases of low-grade B-cell lymphoma that were found to coexpress CD5 and CD10 at the time of initial diagnosis. The first case was classified as small lymphocytic lymphoma; the second as follicle center lymphoma, follicular grade 1; and the third as small B-cell lymphoma otherwise not specified. Currently, the clinical implication of the coexpression of CD5 and CD10 is not known. We describe this finding to highlight the difficulty that may be encountered in classifying lymphomas in cases where this coexpression is present.

Sickle cell anemia

Sickle cell anemia (SCA) is a disease caused by production of abnormal hemoglobin, which binds with other abnormal hemoglobin molecules within the red blood cell to cause rigid deformation of the cell. This deformation impairs the ability of the cell to pass through small vascular channels; sludging and congestion of vascular beds may result, followed by tissue ischemia and infarction. Infarction is common throughout the body in the patient with SCA, and it is responsible for the earliest clinical manifestation, the acute pain crisis, which is thought to result from marrow infarction. Over time, such insults result in medullary bone infarcts and epiphyseal osteonecrosis. In the brain, white matter and gray matter infarcts are seen, causing cognitive impairment and functional neurologic deficits. The lungs are also commonly affected, with infarcts, emboli (from marrow infarcts and fat necrosis), and a markedly increased propensity for pneumonia. The liver, spleen, and kidney may experience infarction as well. An unusual but life-threatening complication of SCA is sequestration syndrome, wherein a considerable amount of the intravascular volume is sequestered in an organ (usually the spleen), causing vascular collapse; its pathogenesis is unknown. Finally, because the red blood cells are abnormal, they are removed from the circulation, resulting in a hemolytic anemia. For the patient with SCA, however, the ischemic complications of the disease far outweigh the anemia in clinical importance.

Cutaneous B-cell lymphoma with signet ring-cell morphology: a clinicopathologic and immunohistochemical study of three cases

Three cases of primary cutaneous B-cell lymphoma with prominent signet ring-cell features are presented. The patients were three men between the ages of 37 years and 74 years (average, 55.5 years). Clinically, the three patients presented with multiple skin nodules. In one patient, the nodules had been present for approximately 5 weeks, although in the two other patients, the nodules were of unknown duration. The lesions were located in the upper extremities (forearm) and measured from 2 cm to 3 cm in diameter. No evidence of lymphadenopathy was observed in any of the patients. Surgical excision of the nodules was performed. Histologically, in two cases, the superficial and deep dermis was replaced by a diffuse cellular proliferation, and in one patient, the tumor cell population adopted a nodular pattern of growth involving adnexal structures and infiltrating the subcutaneous fat. In all cases, the tumors were composed of cells showing signet ring-cell features, with striking indentation of the nuclei toward the periphery of the cell. Immunohistochemical studies using antibodies for B-cell and T-cell markers (L-26 and UCHL) as well as antibodies for leukocyte common antigen, keratin, and kappa and lambda light chains were performed in all cases. The tumor cells showed a positive reaction for leukocyte common antigen, L-26, and lambda light chain restriction. Follow-up information was only available in one patient, who has remained alive and well 2 years after diagnosis without evidence of progression of the disease. The present cases highlight the importance of recognizing this unusual morphologic type of lymphoma so as to arrive at a correct diagnosis.

Is lymphoplasmacytic lymphoma/immunocytoma a distinct entity? A clinicopathologic study of 20 cases

Lymphoplasmacytic lymphoma/immunocytoma (LLI) was defined initially as a small B-cell lymphoma with plasmacytoid or plasmacytic features. Because other types of small B-cell lymphoma, particularly marginal zone B-cell lymphoma may exhibit plasmacytic differentiation, the revised European-American lymphoma classification and World Health Organization has defined LLI more narrowly to exclude other small B-cell lymphomas. The goal of this study was to reevaluate LLI as a clinicopathologic entity. Twenty cases were selected from 43 previously diagnosed as "small lymphocytic lymphoma, plasmacytoid" or "immunocytoma" from 1985 to 1998. Cases fulfilling the criteria for B-cell small lymphocytic lymphoma, follicular lymphoma, marginal zone B-cell lymphoma, or other types of B-cell lymphoma were excluded. The histopathology and immunoreactivity for CD20, CD79a, CD3, CD43, CD23, CD5, kappa, lambda, and immunoglobulins (Ig's) M, G, and A were reviewed, in addition to available clinical findings. There were 13 men and seven women, with a mean age of 69 years. Five patients had documented Waldenström's macroglobulinemia (WM). Three architectural patterns were observed. Pattern A (seven of 20) showed open sinuses, small follicles, and hemosiderosis; pattern B (four of 20) showed hyperplastic follicles; and pattern C (nine of 20) showed diffuse effacement. Epithelioid histiocytes were prominent in patterns B and C but absent in A. Cytologically, six of 20 were polymorphous with 10% to 40% transformed cells; 14 of 20 were lymphoplasmacytic. Five cases showed minor foci of monocytoid B cells. One case showed a composite histology of LLI and small lymphocytic lymphoma. Amyloid was present in two cases. All cases were CD20 and/or CD79a immunoreactive, with two of 20 positive for CD43. Twelve cases were kappa monoclonal and eight cases were lambda monoclonal. Twelve of 17 cases that could be evaluated were positive for IgM and five were positive for IgG. All cases were negative for CD5 and CD23 with the exception of the one case with a composite histology. Eleven of 20 patients with available follow-up died of disease (median, 48 months), and eight of 20 are alive with disease at a follow-up of 6 months to 2 years. LLI does appear to represent a distinct clinicopathologic entity even though it shows morphologic heterogeneity and overlapping features with marginal zone B-cell lymphoma and small lymphocytic lymphoma. Recognition of LLI is important because the overall prognosis may be worse than for other types of small B-cell lymphomas.

Apoptosis, bcl-2 expression, and p53 expression in gastrointestinal stromal/smooth muscle tumors

The authors investigated the relations between outcome and apoptosis, immunohistochemical demonstration of bcl-2 protein, and immunohistochemical staining for p53 protein in patients with gastrointestinal stromal/smooth muscle tumors (GIST). Patients whose tumors demonstrated cellular apoptosis using the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) assay had an improved survival over those whose tumors did not improve. In contrast, patients whose tumors demonstrated staining for bcl-2 protein had a decreased survival compared with those whose tumors did not demonstrate bcl-2. There was no relation between p53 immunoreactivity and survival. These results suggest that inhibition of apoptosis may be associated with malignant behavior in patients with gastrointestinal stromal/smooth muscle tumors.

Splenic inflammatory myofibroblastic tumor (inflammatory pseudotumor): a clinicopathologic and immunophenotypic study of 12 cases

CONTEXT

Inflammatory pseudotumor is an uncommon and enigmatic lesion. The spindle cells found in this tumor have features of myofibroblasts. Because of the indefinite relationship of these lesions with inflammatory fibrosarcoma and their indefinite biologic behavior, inflammatory pseudotumor is currently classified as inflammatory myofibroblastic tumor (IMT). To date, only case reports or small series have been published on these tumors, which are primary in the spleen.

DESIGN

In this study, we describe the clinical, morphologic, and immunophenotypic findings of 12 cases of splenic IMT and examine their relationship to Epstein-Barr virus (EBV).

RESULTS

The patients included 8 women and 3 men, ranging from 19 to 77 years of age (mean, 53 years; median, 60 years). Demographic data were unavailable for 1 patient. Patients generally presented with abdominal pain (n = 5) and fever (n = 4). Associated lesions included renal cell carcinoma (n = 2), colonic adenocarcinoma (n = 1), and cholecystitis (n = 1). All tumors were composed of a bland spindle cell proliferation in association with a variable mixed inflammatory component. There were 2 growth patterns, namely, a cellular spindle cell pattern and a hypocellular fibrous pattern. An immunohistochemical panel confirmed the myofibroblastic nature of the spindle cells. The spindle cells of 2 cases were immunoreactive for EBV latent membrane protein 1, whereas 6 of 10 cases were positive for EBV-encoded RNA using in situ hybridization. Follow-up was available for 8 patients; 6 were alive with no evidence of recurrence and 2 were dead of other causes.

CONCLUSION

Splenic IMTs are uncommon lesions that can be distinguished from other conditions using a combination of clinical, histologic, and immunophenotypic findings. Epstein-Barr virus may play a role in the pathogenesis of splenic IMT, and there may be an association of splenic IMT with concomitant disease or malignancy. Most splenic IMTs have an excellent long-term prognosis.

Primary anaplastic large cell lymphoma of the lung: a clinicopathologic study of five patients

Primary anaplastic large-cell lymphoma is a rare malignancy in the lung. Anaplastic large-cell lymphoma characteristically involves the lymph nodes or skin, with few reports from other sites. We studied the clinical and pathologic features of five cases of anaplastic large-cell lymphoma limited to the lungs. The patients were three women and two men aged 27 to 66 years (mean, 44.6 y) The tumors ranged in size from 1.1 to 5 cm. All patients were CD 30 (Ki-1) positive and CD 15 (LeuM-1) negative. Epithelial membrane antigen immunoreactivity was seen in two patients. Epstein-Barr virus was not detected by immunohistochemistry (four patients tested) or by polymerase chain reaction studies (three patients tested). The immunophenotypes were T cell (n = 3) and null (n = 2). Gene rearrangement studies supported the immunophenotypic findings. One patient who had underlying HIV infection died of infectious complications. One patient died at 6 months. Two patients developed recurrent disease and are alive after 42 and 51 months of follow-up. The remaining patient is alive at 8 years of follow-up without evidence of disease. ALCL can mimic metastatic or primary carcinoma and should be considered in the differential diagnosis of large cell neoplasms of the lung.

Follicle center lymphoma involving the female genital tract: a morphologic and molecular genetic study of three cases

Primary female reproductive system lymphomas are distinctly uncommon, and are defined as lymphomas that present primarily as gynecologic tumors. We describe 3 cases which presented in this location, 1 primary ovarian disease and 2 others presenting the initial manifestations of disseminated lymphoma. Clinical history, follow-up information, and paraffin embedded archival tissue were available for all 3 cases. A panel of immunoperoxidase studies and molecular genetic studies were performed for each case. The primary ovarian follicle center lymphoma was a grade III/III (large cell) while the cases representing secondary involvement were grade I/III (small cell). Immunohistochemistry demonstrated reactivity of the malignant cells in each case with CD20 and bcl-2. In the grade I/III cases the cells were immunoreactive for CD45RA and CD10. Molecular genetic analysis demonstrated the t(14;18) translocation in the case of primary ovarian follicle center lymphoma. Follicle center lymphoma uncommonly presents in the female genital system, and may rarely be primary to this site. Immunoperoxidase and molecular studies in concert with the morphology are invaluable in rendering a correct diagnosis and ensuring correct treatment of the patient.

Splenic angiosarcoma: a clinicopathologic and immunophenotypic study of 28 cases

Primary angiosarcoma of the spleen is a rare neoplasm that has not been well characterized. We describe the clinical, morphologic, and immunophenotypic findings of 28 cases of primary splenic angiosarcoma, including one case that shares features of lymphangioma/lymphangiosarcoma. The patients included 16 men and 12 women, aged 29 to 85 years, with a mean of 59 years and median of 63 years. The majority of patients (75%) complained of abdominal pain, and 25% presented with splenic rupture. The most common physical finding was splenomegaly (71%). Seventeen of 21 patients were reported to have anemia. Macroscopic examination showed splenomegaly in 85% cases. Sectioning revealed discrete lesions in 88% of cases, ranging from well-circumscribed firm nodules to poorly delineated foci of necrosis and hemorrhage associated with cystic spaces. Microscopically, the tumors were heterogenous; however, all cases demonstrated at least a focal vasoformative component lined by atypical endothelial cells. Solid sarcomatous, papillary, and epithelioid growth patterns were observed. The solid sarcomatous component resembled fibrosarcoma in two cases and malignant fibroushistiocytoma in one case. Hemorrhage, necrosis, hemosiderin, extramedullary hematopoiesis, and intracytoplasmic hyaline globules were frequently identified. A panel of immunohistochemical studies revealed that the majority of tumors were immunoreactive for at least two markers of vascular differentiation (CD34, FVIIIRAg, VEGFR3, and CD31) and at least one marker of histiocytic differentiation (CD68 and/or lysozyme). Metastases developed in 100% of patients during the course of their disease. Twenty-six patients died of disease despite aggressive therapy, whereas only two patients are alive at last follow-up, one with disease at 8 years and the other without disease at 10 years. In conclusion, primary splenic angiosarcoma is an extremely aggressive neoplasm that is almost universally fatal. The majority of splenic angiosarcomas coexpress histiocytic and endothelial markers by immunohistochemical analysis, which suggest that some tumors may originate from splenic lining cells.

T-cell lymphoma presenting in the breast: a histologic, immunophenotypic and molecular genetic study of four cases

Primary non-Hodgkin's lymphoma of the breast is uncommon. Most primary breast lymphomas are of B-cell phenotype, with only rare cases showing a T-cell phenotype. In this study, we report the clinicopathologic features of four cases of T-cell lymphoma in the breast. The patients all were female with a mean age of 48 years (range, 13 to 77 years). All cases showed immunoreactivity in paraffin-embedded tissue for T-cell markers CD3, CD45RO, and CD43. beta F1 was positive in three of four cases. The four cases were further subclassified as anaplastic large cell lymphoma (CD30 positive) of T-immunophenotype; natural killer/T-cell lymphoma; peripheral T-cell (CD4 positive), large cell type; and peripheral T-cell (CD8 positive, T-cell intracellular antigen positive), medium cell type. Three of the four cases were monoclonal for T-cell receptor beta and/or T-cell receptor gamma. The one case of natural killer/T-cell lymphoma was negative for monoclonality with both T-cell receptor beta and gamma by molecular diagnostic studies. In all cases, IgH was negative. Follow-up was obtained in three cases. Two patients died within less than 1 year after the diagnosis. The third patient died within 18 months of the diagnosis. Our results suggest an aggressive clinical course for T-cell lymphomas that present in the breast.

Extranodal marginal zone B-cell lymphoma of the skin: a morphologic and immunophenotypic study of 11 cases

Extranodal marginal zone B-cell lymphoma (MZBL) is a recently recognized low-grade lymphoma that has been well described in other organs such as the stomach and salivary gland. It has only recently been described in skin, where it may be difficult to distinguish from reactive processes and other types of B-cell lymphoma such as follicle center lymphoma. These cases may have been classified as pseudolymphomas in the past. Extranodal MZBL was referred to as mucosa-associated lymphoid tissue (MALT) lymphoma before the Revised European-American Classification of Lymphoid Neoplasms was published in 1994. Important histologic features that aid in the diagnosis of MALT lymphoma are atypical lymphocytes (centrocyte-like and monocytoid B cells) often admixed with plasmacytoid lymphocytes, a prominent plasma cell component, lymphoepithelial lesions, intranuclear inclusions (Dutcher bodies), and reactive germinal centers that may be colonized by neoplastic cells. Immunophenotypic studies demonstrating a B-cell phenotype, light chain restriction, coexpression of CD43, and staining of atypical lymphocytes with bcl-2 support a diagnosis of MALT lymphoma. We studied 11 cases of extranodal MZBL of the skin from the Armed Forces Institute of Pathology files. There were six women and five men ranging in age from 30 to 69 years (median, 54 years). The anatomical sites included the trunk, head and neck areas, and upper extremities. There were no other sites of disease besides the skin in any of the cases. The follow-up period ranged from 5 months to 8 years (median, 24 months). Histologic results included an atypical lymphoid infiltrate with B-cell phenotype, reactive germinal centers, and a variable plasma cell component in all cases. No Dutcher bodies or lymphoepithelial lesions were noted. Extranodal MZBL of skin is a diagnostic challenge because of a heterogeneous cellular infiltrate that may be interpreted as a reactive process. The most significant neoplasm with which it is confused is follicular lymphoma. It is important to recognize the characteristic histologic and immunophenotypic features of extranodal MZBL so that the appropriate therapeutic approach may be applied.

Malignant lymphoma of the thyroid gland: a clinicopathologic study of 108 cases

We report a retrospective clinicopathologic study of 108 primary thyroid gland lymphomas (PTLs), classified using the REAL and proposed WHO classification schemes. The patients included 79 women and 29 men, with an average age of 64.3 years. All patients presented with a thyroid mass. The PTLs were classified as marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) or MZBL (n = 30), diffuse large B-cell lymphoma (DLBCL) with MZBL (n = 36), DLBCL without MZBL (n = 41), and follicle center lymphoma (FCL; n = 1). Excluding the FCL, features of lymphomas of MALT-type were identified in all groups, despite a follicular architecture in 23% of cases. Lymphocytic thyroiditis (LT) was identified in 94%. Ninety-one percent of patients presented with stage IE or IIE disease, whereas 69% had perithyroidal soft tissue infiltration. All patients were treated with surgical excision followed by adjuvant therapy (76%): chemotherapy (15%), radiation (19%), or a combination of radiation and chemotherapy (42%). Disease-specific survival was 82% at last follow up (mean, 82.8 mos) and 79% at 5 years. Statistically, stages greater than IE, presence of DLBCL, rapid clinical growth, abundant apoptosis, presence of vascular invasion, high mitotic rate, and infiltration of the perithyroidal soft tissue were significantly associated with death with disease. No patients with MZBL or stage IE disease died with disease. In summary, PTLs typically occur in middle- to older-aged individuals as a thyroid mass, with a predilection for females. Despite their histologic heterogeneity and frequent simulation of other lymphoma subtypes, virtually all PTLs are lymphomas of MALT-type arising in the setting of LT. Mixed DLBCL and MZBL are common. Overall, PTLs have a favorable outcome with appropriate therapy, but prognosis depends on both clinical stage and histology. MZBL and stage IE tumors have an excellent prognosis, whereas tumors with a large cell component or DLBCL or stage greater than IE have the greatest potential for a poor outcome.

Immunoperoxidase detection of CD10 in Precursor T-lymphoblastic lymphoma/leukemia: a clinicopathologic study of 24 cases

CONTEXT

CD10 was originally reported in non-T-cell lymphoblastic lymphomas/leukemias. It has since been identified, however, in a minority of cases of T-lympho-blastic lymphoma/leukemia and other hematopoietic and nonhematopoietic entities. The usual method for the detection of CD10 previously required fresh tissue. A new antibody for CD10 (56C6) in paraffin embedded tissue sections, however, has recently become available.

OBJECTIVE

To study the expression of CD10 in paraffin sections of T-lymphoblastic lymphoma/leukemia using monoclonal antibody 56C6.

DESIGN

Twenty-four cases of T-lymphoblastic lymphoma/leukemia in various anatomic sites were studied. Immunohistochemical analysis with CD10 and a panel of other hematolymphoid antibodies was performed in all 24 cases. Gene rearrangement studies for the T-cell receptor by the polymerase chain reaction were performed in 18 of 24 cases.

RESULTS

All cases were positive with at least 2 T-cell markers. In 15 (63%) of 24 cases CD10 was positive. T-cell receptor gene rearrangement was detected in 10 of 18 cases.

CONCLUSIONS

Immunodetection of CD10 in T-lympho-blastic lymphoma/leukemia using monoclonal antibody 56C6 is common. This finding is useful in the evaluation of T-cell neoplasms.

Extramedullary manifestation of multiple myeloma (systemic plasmacytoma) that simulates hemangioma

We describe 2 cases of a unique type of extramedullary manifestation of multiple myeloma (systemic plasmacytoma) that presented as subcutaneous nodules and mediastinal mass, respectively. Both lesions had a similar morphologic appearance, with dilated vascular-like lumina that was separated by thin fibrovascular septa, filled with erythrocytes, and lined by mature and immature plasma cells and plasmacytoid cells. The plasma and plasmacytoid lining cells showed kappa light chain restriction in both cases, consistent with a B-cell monoclonal process. The lining cells were also focally positive for epithelial membrane antigen but were negative for endothelial cell markers. Abundant delicate capillaries were seen in the septa that separated the vascular lumina, mimicking a vascular tumor. Furthermore, we believe that our cases are different from the previously described blood lakes in a plasmacytoma by the presence of well-formed fibrovascular septa that separated the vascular-like spaces. Neoangiogenesis propagated by myeloma cells may contribute to this unusual morphologic manifestation of extramedullary manifestation of multiple myeloma.

Nodular lymphoid hyperplasia of the lung: a clinicopathologic study of 14 cases

Nodular lymphoid hyperplasia is a controversial entity in which its existence in the lung has been doubted. The current opinion is that most, if not all, such cases represent extranodal marginal zone B-cell lymphomas masquerading as reactive lesions. We found 14 cases of nodular lymphoid hyperplasia in the files of the Pulmonary Department at the Armed Forces Institute of Pathology from 1974 through 1998. All had clinical histories and hematoxylin-eosin slides. In 12 of 14 with paraffin blocks, we applied immunohistochemical antibodies for CD20, CD3, CD43, CD5, bcl-2, bcl-1, CD45RA, and kappa and lambda immunoglobulin light chains. Molecular genetic analysis was performed on paraffin sections in 10 of 14 by the polymerase chain reaction for rearrangements of the immunoglobulin heavy chain gene and the minor and major break-point regions of the chromosomal translocation t (14;18). There were eight women and six men ranging in age from 19 to 80 years (median, 65 yrs). Most lesions (71%) were incidental findings on routine chest x-rays. Most patients (64%) had a single lesion by chest x-ray whereas the remainder had two to three lesions, except for one patient who had "multiple" lesions. There was associated regional lymphadenopathy in five of 14 cases (36%) which, on biopsy, proved to be reactive follicular hyperplasia. The only treatment was surgical excision. Of the seven patients with follow-up information from 8 months to 6 years (mean, 30 mos), none had clinical recurrence and no patient died of disease. The histology and immunophenotype of the lesions were strikingly similar, including abundant reactive germinal centers, intense interfollicular polyclonal plasmacytosis, and a variable degree of interfollicular fibrosis. No case showed a molecular rearrangement of the immunoglobulin heavy chain gene or the minor or major break-point region of the t (14;18). We conclude that nodular lymphoid hyperplasia of the lung, although rare, does exist and deserves its place in the spectrum of reactive pulmonary lesions that ranges from follicular hyperplasia to diffuse hyperplasia of the bronchus-associated lymphoid tissue (lymphoid interstitial pneumonitis).

Paraffin immunohistochemistry as an adjunct to hematopathology

In the past two decades, there have been a number of dramatic advances in immunology that have subsequently affected immunohistochemistry. These have had a substantial impact on all phases of laboratory medicine, especially surgical pathology. Many hospital laboratories use immunohistochemical analysis on paraffin-embedded tissue sections as routinely as other special histochemical techniques. Hematopathology, in particular, has become increasingly reliant on the immunohistochemical antibody technique. This method aids in the identification of lineage-associated or lineage-restricted antigens in hematolymphoid neoplasms. The demonstration of kappa or lambda light-chain restriction is a good indicator of monoclonality in B-cell processes, aiding in the distinction between benign reactive hyperplasia and malignant lymphoma. Increasing numbers of antibodies that react to cluster differentiation cell surface antigens have become available for use in paraffin-embedded sections, obviating the need for frozen tissue in many cases. This facilitates the collection, processing, shipping, and storage of tissue specimens for immunohistochemical studies. This report will discuss the basic concepts in the immunohistochemical technique and show its applicability to hematopathology. It will also describe the most relevant antigens/antibodies and how they are used in antibody panels for the diagnosis of benign and malignant hematolymphoid lesions.

Antiapoptotic marker Bcl-X(L), expression on Reed-Sternberg cells of Hodgkin's disease using a novel monoclonal marker, YTH-2H12

Inhibitors of apoptosis may regulate tissue differentiation and promote cell survival in neoplasia. A new apoptosis inhibitor of the bcl-2 gene family, bcl-X(L), was recently found in some types human neoplasia but not in normal tissue. We investigated bcl-X(L) expression in 419 cases of normal and neoplastic lymphoid lesions using immunohistochemistry with the monoclonal antibody bcl-X(L) (YTH-2H12). Ninety-four percent (141/150) of classic Hodgkin's disease (HD) were positive for bcl-X(L) with strong intensity in most Reed-Sternberg (RS) cells. Forty-eight percent (38/80) of nodular lymphocyte predominance (LPHD) were positive. In the non-Hodgkin's lymphomas (NHL), bcl-X(L) was expressed in a low percentage of cases (< 20%), with the exception of follicle center lymphoma, grade III/III (78%). All reactive hyperplastic lesions were negative for bcl-X(L). RS cells, which expressed bcl-X(L), were not labeled by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). We found RS cells expressing bcl-X(L) were absent of DNA fragmentation (apoptosis). Our data provide evidence that bcl-X(L) is abnormally expressed in the RS cells of HD and some types of NHL raising speculation that inhibition of apoptosis may be important in the pathogenesis of lymphoma, specifically HD. In addition, the previously reported correlation between bcl-X(L) and Epstein-Barr virus expression in HD was not supported by this study.

P53 and cyclin D1 staining patterns of malignant and premalignant oral lesions in age-dependent populations

OBJECTIVE

Recent epidemiologic studies have identified a trend of increasing cancer incidence in younger patients. The purpose of this study was to determine whether this might be reflected by different molecular mechanisms for tumor development.

STUDY DESIGN

Dysplastic and malignant oral lesions from age-distinct patient populations were immunohistochemically analyzed for expression of p53 and cyclin D1. Chi-square analysis was used to determine statistical significance.

RESULTS

Eighty-two percent of "older" and 75% of "younger" carcinomas stained positively with p53; 63% of carcinomas in the older population and 55% of carcinomas in the younger population showed cyclin D1 positivity. Dysplasias showed similar cyclin D1 staining in both groups. Interestingly, 100% of "younger" dysplasias stained positively for p53, whereas 35.3% of "older" dysplastic lesions showed immunoreactivity. Staining of carcinomas was not statistically significant, whereas p53 staining of dysplasias proved highly significant (P < .025).

CONCLUSIONS

p53 immunoreactivity is detectable at an earlier stage of carcinogenesis in younger patients than in the traditional risk population for oral cancer.

Silicone gel-filled breast and testicular implant capsules: a histologic and immunophenotypic study

The immunophenotypic characteristics of silicone gel-filled breast and testicular implant capsules have not been well described. Therefore, we studied 17 paraffin-embedded tissue sections from 9 breast implant patients and 1 testicular implant patient to assess the type and extent of inflammatory responses present. Immunohistochemical analyses were performed on paraffin-embedded tissue sections for expression of CD20, CD45RO, betaF1, CD68, CD44, kappa and A immunoglobulin light chains, and bcl-XL (a member of the bcl-2 family of proteins involved in apoptosis). The most common histologic features included prominent T-cell and foamy macrophage reactions with foreign body giant cells and granulomas in a dense fibrovascular connective tissue. Foci of polyclonal plasma cells and acute inflammatory cells were variably present. In one case, there was reactive germinal center formation, a novel finding. A "pseudosynovium" at the implant capsule interface was present in the majority of cases as previously described; it showed reactivity with CD68. Thin strands of highly refractile, nonpolarizable material, consistent with silicone, were regularly noted in intra- and extracellular locations. The immunohistochemical results included reactivity of the majority of lymphocytes with CD45RO and/or betaF1 (confirming an anamnestic reactive T-cell phenotype), and reactivity of the macrophages, giant cells, and "pseudosynovium" with the macrophage/histiocyte marker, CD68. The reactive germinal centers were positive for CD20. Reactivity for CD44, an activation and intracellular adhesion marker, was frequently observed in the foamy macrophages and foreign body giant cells and has not been previously reported. The plasma cells demonstrated polyclonal immunoglobulin light-chain reactivity, consistent with a reactive process. These findings suggest that silicone implants induce chronic inflammatory responses in many adjacent capsules, which consist of anamnestically responding T cells, reactive B-lymphocytes, and macrophages.

Enhanced sensitivity with a novel TCRgamma PCR assay for clonality studies in 569 formalin-fixed, paraffin-embedded (FFPE) cases

BACKGROUND

Clonal rearrangement of genes encoding the immunoglobulins (Ig) and T-cell antigen receptors (TCR) are considered to be useful markers for the diagnosis of lymphoma and for determining the clonal origins of B- and T-cell populations in lymphoid neoplasms.

METHODS AND RESULTS

Polymerase chain reaction-based clonality assays for TCRgamma, TCRbeta, and immunoglobulin (Ig) heavy chain (IgH) gene rearrangements were evaluated for diagnostic sensitivity and specificity in 569 formalin-fixed, paraffin-embedded (FFPE) tissues. Combined TCRbeta and TCRgamma assays enhanced the routine detection of TCR clonality to 90% of all peripheral T-cell lymphoma (PTCL) cases. IgH clonality was detected in 59% of 241 peripheral B-cell lymphoma (BCL) cases and 6% of 169 PTCL cases. Of 452 lymphomas, 5% could not be classified phenotypically as B or T lineage after immunohistochemical and clonality studies. Of all BCL cases analyzed, 24% had detectable TCRbeta and/or TCRgamma clonality. Of these BCL with biclonal results, 47% were extranodal lymphomas from skin and various tissues.

CONCLUSIONS

Clonality assays were useful for distinguishing reactive or benign lymph nodes from neoplastic lymphoid infiltrates in most cases. The inclusion of TCRb and TCRg assays in the assessment of lymphomas results in a significant increase in the sensitivity of clonality detection, but is of limited utility in assessing the T- or B-cell phenotype of the tumor.

Frequent loss of KAI1 expression in squamous and lymphoid neoplasms. An immunohistochemical study of archival tissues

The metastasis suppressor gene KAI1 was identified by its ability to inhibit the formation of pulmonary metastases in experimental models for prostatic carcinoma. Down-regulation of this gene may be correlated with the invasive phenotype in melanomas and colon and bladder carcinomas and with the metastatic phenotype in carcinomas of the lung, breast, prostate, and pancreas. The goal of our study was to establish an immunohistochemical method to detect KAI1 expression in archival tissues. Using cell lines with known KAI1 levels and paraffin-embedded KAI1 positive tissues as controls, we observed strong membrane staining in lymphoid follicular centers and squamous epithelia. We then demonstrated the utility of our assay by studying KAI1 expression in 34 lymphoid and 57 squamous lesions. All eight reactive lymph nodes were KAI1 positive. In contrast, three of 13 follicular small cleaved and five of 13 diffuse large cell lymphomas were KAI1 negative. Seventy-nine percent (37 of 47) of invasive squamous cell carcinomas from the lung (n = 15), head and neck (n = 18), and cervix (n = 14) showed extensive KAI1 down-regulation. Loss of KAI1 expression was also found in a subset of 10 high-grade cervical dysplasias. Our data show that (i) immunohistochemistry is a suitable technique for evaluating KAI1 expression in archival tissues; (ii) KAI1 was not expressed in a subset of both low-grade and high-grade lymphomas; and (iii) there was extensive down-regulation of KAI1 in squamous cell carcinomas, suggestive of an important role of the gene in the suppression of invasion in these malignancies.

CD45 (leukocyte common antigen) immunoreactivity in metastatic undifferentiated and neuroendocrine carcinoma: a potential diagnostic pitfall

Leukocyte common antigen (CD45/LCA) and keratin expression are generally mutually exclusive in diagnostic surgical pathology. CD45 reactivity is a reliable indicator of the hematolymphoid nature of a tumor, whereas keratin reactivity is typical of epithelial differentiation (carcinomas and some sarcomas). Some lymphomas, however, might lack detectable CD45 expression, whereas occasional ones might express keratins. CD45 immunoreactivity has been considered exquisitely specific for hematopoietic cells. We report three undifferentiated or neuroendocrine carcinomas that showed membrane-associated immunoreactivity for CD45 in addition to showing distinctive keratin cocktail (AE1/AE3) and epithelial membrane antigen reactivity (all cases); also, keratin 7 was demonstrated in one case and keratin 19 in another. Two cases were lymph node metastases of undifferentiated carcinomas, one of them from the lungs and the other of an unknown origin; the former case showed neuroendocrine features. The third case represented a pulmonary large-cell undifferentiated carcinoma. These cases were negative for lineage-specific leukocyte antigens and did not show clonal immunoglobulin heavy-chain gene rearrangements. Electron microscopic studies demonstrated desmosomes and keratin-like tonofilaments in all three cases, thus confirming the epithelial nature of these tumors. The exceptional membrane staining for CD45 seen in these undifferentiated carcinomas might be comparable to experimentally detected incorporation of leukocyte antigens into the cell membranes of nonleukocytic cells in a leukocyte-rich environment. This rare diagnostic pitfall should be considered in the diagnostic surgical pathology of undifferentiated tumors. It is best avoided by employing a panel of leukocyte and epithelial antigens and by use of electron microscopy, if possible.

Differential expression of cyclin D1 in mantle cell lymphoma and other non-Hodgkin's lymphomas

Mantle-cell lymphomas are associated with a characteristic chromosomal translocation, t(11;14)(q13;q32). This translocation involves rearrangement of the bcl-1 proto-oncogene from chromosome 11 to the immunoglobulin heavy chain gene on chromosome 14, resulting in an overexpression of cyclin D1 mRNA (also known as bcl-1 and PRAD1). In the current study performed on paraffin-embedded tissue, cyclin D1 mRNA could be detected in 23 of 24 mantle-cell lymphomas by reverse transcription polymerase chain reaction (RT-PCR) whereas only 9 of 24 demonstrated a t(11;14) by PCR. However, we also found that cyclin D1 mRNA could be detected in the majority (11 of 17, 65%) of non-mantle-cell lymphomas and in a minority of atypical lymphoid hyperplasias (3 of 7, 43%). Cyclin D1 mRNA expression was not observed in floridly reactive lymph nodes (0 of 9) or in unstimulated lymph nodes (0 of 20), suggesting that it is a sensitive adjunct marker for malignant lymphoproliferative processes, but not specific for mantle-cell lymphoma. A semiquantitative RT-PCR assay was developed that compared the ratio of cyclin D1 to the constitutively expressed gene beta2-microglobulin. Using this assay on a limited number of our specimens, cyclin D1 overexpression in mantle-cell lymphoma could be reliably distinguished from its expression in other non-Hodgkin's lymphomas. This assay for cyclin D1 expression, designed for formalin-fixed, paraffin-embedded tissue, was a very sensitive and specific marker for mantle-cell lymphoma.

Expression of CD44 (HCAM) in small lymphocytic and mantle cell lymphoma

Small lymphocytic lymphoma (SLL) and mantle cell lymphoma (MCL) are small B-cell lymphomas that share many morphological and immunophenotypic features, both expressing the T-cell antigen CD5. Because of this, there is speculation that these two lymphomas may have a common origin, both arising from the mantle zone of the lymph node. CD44 (HCAM), a glycoprotein "homing receptor," has been reported as a marker of small B-cell lymphomas for determining behavior as well as the nodal cell of origin. Intensity of CD44 expression also has been correlated with dissemination of lymphoma. We studied 50 cases with classic features of SLL (30 cases) or MCL (20 cases). Immunophenotypic analysis was performed on paraffin sections. All cases of MCL and SLL were CD20 positive; CD5 was expressed in 19 of 25 (76%) SLL and 11 of 15 (73%) MCL. Cyclin D1 was expressed in 11 of 17 (76%) MCL and no cases of SLL. CD43 coexpression was seen in 27 of 29 (93%) SLL and 17 of 19 (89%) MCL. CD23 was positive in 25 of 28 (89%) SLL and 2 of 20 (10%) MCL. Bcl-2 was positive in 18 of 22 (82%) SLL and 15 of 16 (94%) MCL. CD44 was positive with moderate to strong intensity in 11 of 30 SLL and 15 of 20 MCL. Peripheral blood involvement did not correlate with CD44 immunoreactivity. MCL tended to have intense CD44 immunoreactivity, whereas SLL tended to show weaker CD44 intensity. This trend in the intensity of CD44 in MCL suggests that CD44 may be helpful in distinguishing SLL from MCL and possibly elucidating the origin of these CD5-positive B-cell neoplasms.

The blastic variant of mantle cell lymphoma arising in Waldeyer's tonsillar ring

We present three cases of blastic mantle cell lymphoma with an unusual initial manifestation in Waldeyer's ring with methods for differentiating it from other blastic neoplasms of the head and neck. All cases presented with a feeling of fullness in the area of the mass. Morphologically, the tumours were blastic with a high mitotic rate (three to nine per high power field). All were B-cell phenotype with coexpression of CD43. In all cases cyclin D1 and bcl-2 were positive and CD23 negative. Blastic mantle cell lymphoma occurring in Waldeyer's tonsillar ring may be mistaken for other high grade haematopoietic neoplasms. Immunohistochemistry and awareness of this type of lymphoma are helpful in differentiating it from other neoplasms.

Reticulum cell neoplasms of lymph nodes: a clinicopathologic study of 11 cases with recognition of a new subtype derived from fibroblastic reticular cells

Lymph nodes contain nonlymphoid accessory cells including follicular dendritic cells (FDCs), interdigitating dendritic cells (IDCs) and fibroblastic reticular cells (FBRCs). Neoplasms derived from FDCs are uncommon, and those of IDC origin are even more rare. We report the clinicopathologic features of 11 reticulum cell neoplasms, including 2 of FBRC origin. There were seven male patients and four female patients ranging in age from 13 to 73 years. All cases involved lymph nodes (cervical or supraclavicular-6 cases), (abdominal--2 cases), epitrochlear (1 case); two had more than one site of involvement (cervical lymph node and mediastinum--1 case, cervical and abdominal lymph nodes--1 case). One case of FDC tumor had concomitant Castleman's disease, plasma cell variant. Each neoplasm showed similar histology with oval-to-spindle-shaped cells in a storiform or fascicular pattern. Based on immunophenotypic findings, the neoplasms were classified as FDC (five cases), IDC (two cases), FBRC (three cases), and reticulum cell neoplasm, not otherwise specified (one case). The FDC tumors showed immunoreactivity for CD21 or CD35, vimentin, and CD68. The IDC tumors showed strong positivity for S-100 protein and variable positivity for CD68 and CD1a. The cases derived from FBRCs were positive for vimentin, desmin, and smooth-muscle actin. The neoplasm classified as reticulum cell neoplasm, not otherwise specified had similar morphologic features but showed only equivocal positivity for CD68 and vimentin. Follow-up was available for 9 of 11 (82%) cases with a mean of 3.5 years. Four of five patients with FDC tumors were alive with disease when last seen; the fifth is alive and well with no evidence of disease at 4-year follow-up. One patient with IDC tumor had a recurrence in a different nodal site. Two patients with FBRC tumor were disease free at follow-up of 2 years and 8 years, respectively. The patient with reticulum cell neoplasm, not otherwise specified, was alive and disease free 8 years after diagnosis.

Loss of tumor suppressor gene expression in high-grade but not low-grade non-Hodgkin's lymphomas

The products of the MTS1/CDKN2 and retinoblastoma (RB) tumor suppressor genes, p16 and pRB, act as agonists in controlling the late G1 cell cycle checkpoint. Inactivation of either gene occurs in a wide range of human malignant neoplasms. Data on the expression of both genes in the same set of malignant lymphoid neoplasms are scarce. We studied the p16/pRB pathway in low-grade and high-grade non-Hodgkin's lymphomas, using immunohistochemical techniques. Paraffin sections of 9 reactive lymph nodes and 43 low-grade and 60 high-grade malignant lymphomas were reacted with antibodies against pRB and p16. All benign lymph nodes showed a normal pattern of RB and MTS1/CDKN2 expression. Of 101 evaluable lymphomas, only a single high-grade tumor displayed loss of RB reactivity. Loss of p16 was identified in 14 of 55 evaluable high-grade lymphomas but not in any of the low-grade lesions. All but 3 of the RB- and p16-negative cases were diffuse large cell lymphomas, for an abnormality rate of 55% in this category. While loss of RB function was a rare event in human lymphomagenesis, p16 was absent in some 25% of high-grade non-Hodgkin's lymphomas; diffuse large cell lymphomas were the primary target of tumor suppressor gene inactivation.

Bcl-2 immunohistochemistry in a surgical series of non-small cell lung cancer patients

The bcl-2 gene is implicated in oncogenesis by its ability to prolong cell survival through the inhibition of apoptosis, without increasing cell proliferation. An association between immunohistochemical staining for bcl-2 protein and the histological type and prognosis of non-small cell carcinoma was hypothesized by Pezzella et al. (N Engl J Med 329:690-694, 1993). In a case series, we stained formalin-fixed, paraffin-embedded tumor tissue from 106 surgical non-small cell lung cancer patients with an antibody to bcl-2 protein (DAKO clone 124, Carpinteria, CA). The resulting bcl-2 staining data were evaluated for associations with demographic, histological, immunohistochemical, and genetic features, including p53 mutations. Bcl-2 staining was observed in tumors from 29 of 106 (27%) of subjects, but was significantly less frequent in subjects' adenocarcinoma histology (8 of 55, 14.6%) (P = .007). This finding persisted after adjustment for age, gender, stage, grade, smoking history, and disease-free survival. In univariate analyses, no association was seen with age, weight, body mass index, gender, or pack-years smoking; tumor grade, stage, or patient performance status; p53 or c-erbB2 immunohistochemical staining, or p53 mutations. These data agree with earlier reports that bcl-2 staining is less common in adenocarcinomas; however, our data do not support the hypothesis that bcl-2 staining confers a better prognosis overall, in squamous cell carcinoma, or in an older patient population.

Detection of Epstein-Barr virus in transformations of low-grade B-cell lymphomas after fludarabine treatment

Fludarabine is a highly effective chemotherapeutic agent for chronic lymphocytic leukemia/small lymphocytic lymphoma and is also active in other B-cell lymphoproliferative disorders. Although highly efficacious in destroying the malignant B-cells, fludarabine also causes T-cell lymphopenia and immunosuppression. We present five patients given fludarabine for low-grade B-cell lymphoproliferative disorders who showed transformation of the primary neoplasm to a higher grade tumor. Immunohistologic antibody studies were performed on paraffin-embedded tissue sections of the initial tissue (when available) and on the follow-up biopsy specimens for CD20, CD3, CD45RO, CD43, CD30, CD15, and latent membrane protein (LMP-1) for Epstein-Barr virus (EBV). The initial diagnoses in these five patients included chronic lymphocytic leukemia/small lymphocytic lymphoma (three cases), follicle center lymphoma (one case), and Waldenstrom's macroglobulinemia (one case). All of the follow-up biopsy specimens showed scattered Hodgkin's-like cells, and two of the five also showed foci of large-cell transformation. The Hodgkin's-like cells showed CD30 immunoreactivity in four of the five cases and CD15 immunoreactivity in three of the five. Strong immunoreactivity of the large, atypical, Hodgkin's-like cells for LMP-1 of EBV was noted in four cases; in the remaining case, this finding was equivocal. In situ hybridization for EBV-encoded RNA was positive in four of the five cases. Molecular studies by polymerase chain reaction (PCR) showed the presence of EBV in three of the five cases. PCR for detection of immunoglobulin heavy chain demonstrated identical monoclonal rearrangements in the original lymphoma and transformation in one case with available material. The CD4 lymphocyte count in each patient was less than 550/microL, indicating cellular dysfunction. Transformation of low-grade non-Hodgkin's lymphomas after fludarabine therapy might be associated with EBV and severe immunosuppression.

Histologically discordant lymphomas with B-cell and T-cell components

We describe the clinical, histologic, immunophenotypic, and genotypic features of five cases of histologically discordant lymphomas with B-cell and T-cell components. Three patients presented with B-cell lymphoma; T-cell lymphoma subsequently developed. One patient presented with T-cell lymphoma; B-cell lymphoma subsequently developed. One patient presented with synchronous B-cell and T-cell lymphomas. There were three men and two women. The median age at the initial diagnosis of lymphoma was 66 years. The mean interval between the development of the two lymphomas was 83 months. All patients died of disease. The mean survival was 96 months after the initial diagnosis of lymphoma and 14 months after the diagnosis of the histologically discordant lymphoma. Epstein-Barr virus was found in two cases--the B-cell lymphoma in the patient who presented with synchronous lymphomas, and the subsequent T-cell lymphoma in one of the patients who presented with B-cell lymphoma. Based on the results of immunophenotypic and genotypic analyses, these cases likely represent the occurrence of two distinct lymphoid neoplasms rather than histologic progression of the same neoplastic clone. Furthermore, a subset of these cases are Epstein-Barr virus-associated.

Gastric "pseudolymphoma": a retrospective morphologic and immunophenotypic study of 97 cases

BACKGROUND

The term "pseudolymphoma" has been used to describe lymphoid lesions that show: 1) borderline features between hyperplasia and neoplasia or 2) benign tumor-like enlargement of lymphoid tissue. The term pseudolymphoma has been applied to lesions in many anatomic locations, with the stomach being one of the more common sites. In spite of the frequent use of this term, neither the histologic criteria nor the clinical significance of this lesion have ever been clearly defined. Since the description of mucosa-associated lymphoid tissue (MALT) and its corresponding MALT-type lymphomas, the value of the term gastric pseudolymphoma has come into question.

METHODS

The authors reviewed all cases diagnosed as gastric pseudolymphomas at the Armed Forces Institute of Pathology from 1970 to 1985. This period predated the description of low grade B-cell lymphoma of MALT-type. The cases were reclassified in light of current criteria and correlated with immunohistochemical findings and follow-up information. No patients were treated with chemotherapy or radiation therapy.

RESULTS

Seventy-seven of 97 cases formerly diagnosed as pseudolymphoma were determined to be malignant lymphomas; the majority (51 cases) were extranodal marginal zone B-cell lymphomas (MALT-type). The remaining cases included reactive lymphoid hyperplasia associated with chronic follicular gastritis (15 cases) and atypical lymphoid infiltrates (5 cases).

CONCLUSIONS

Most cases previously considered to be gastric pseudolymphomas are, by current criteria, malignant lymphomas. A small proportion are benign reactive lymphoid hyperplasias. Those cases of borderline or inconclusive nature are best diagnosed as atypical lymphoid infiltrates. The term gastric pseudolymphoma should be abandoned.

Gastric "pseudolymphoma": a retrospective morphologic and immunophenotypic study of 97 cases

BACKGROUND

The term "pseudolymphoma" has been used to describe lymphoid lesions that show: 1) borderline features between hyperplasia and neoplasia or 2) benign tumor-like enlargement of lymphoid tissue. The term pseudolymphoma has been applied to lesions in many anatomic locations, with the stomach being one of the more common sites. In spite of the frequent use of this term, neither the histologic criteria nor the clinical significance of this lesion have ever been clearly defined. Since the description of mucosa-associated lymphoid tissue (MALT) and its corresponding MALT-type lymphomas, the value of the term gastric pseudolymphoma has come into question.

METHODS

The authors reviewed all cases diagnosed as gastric pseudolymphomas at the Armed Forces Institute of Pathology from 1970 to 1985. This period predated the description of low grade B-cell lymphoma of MALT-type. The cases were reclassified in light of current criteria and correlated with immunohistochemical findings and follow-up information. No patients were treated with chemotherapy or radiation therapy.

RESULTS

Seventy-seven of 97 cases formerly diagnosed as pseudolymphoma were determined to be malignant lymphomas; the majority (51 cases) were extranodal marginal zone B-cell lymphomas (MALT-type). The remaining cases included reactive lymphoid hyperplasia associated with chronic follicular gastritis (15 cases) and atypical lymphoid infiltrates (5 cases).

CONCLUSIONS

Most cases previously considered to be gastric pseudolymphomas are, by current criteria, malignant lymphomas. A small proportion are benign reactive lymphoid hyperplasias. Those cases of borderline or inconclusive nature are best diagnosed as atypical lymphoid infiltrates. The term gastric pseudolymphoma should be abandoned.

Childhood Hodgkin's disease in the United States: an analysis of histologic subtypes and association with Epstein-Barr virus

Hodgkin's disease (HD) typically has a bimodal age distribution and is less common than non-Hodgkin's lymphoma in the pediatric age group, especially in very young children. Recent reports described a high prevalence of Epstein-Barr virus (EBV) in HD from developing countries in both adult and pediatric populations. In this series, we studied with immunohistochemical analysis 44 cases of pediatric HD from the United States to investigate the association with EBV in developed countries and to determine which subtypes occur in this group. The 44 cases (40 boys, 4 girls; male-to-female ratio, 10:1) were categorized as nodular lymphocyte predominance in 16 (36.4%) of 44; nodular sclerosis in 13 (29.5%); and mixed cellularity in 4 (9.1%). Eleven of the cases were difficult to subclassify by the usual morphologic and immunophenotypic criteria. Of these, eight (18.1%) were designated interfollicular HD, and three were classified as HD "not otherwise specified." EBV LMP was positive in 38.6% of cases: 5 (38.5%) of the 13 with nodular sclerosis; 3 (75%) of the 4 with mixed cellularity; 1 (6.0%) of the 16 with nodular lymphocyte predominance; 7 (87.5%) of the 8 with interfollicular HD; and 1 (33.3%) of the 3 with HD "not otherwise specified." There was a strong association between the age of the patient and EBV expression. In children 4 years or younger, all of the 3 cases were LMP positive; in the 5- to 9-year-old age group, 8 (61.5%) of 13 were LMP positive; and in the 10- to 15-year-old group, only 21.4% were positive. Our results confirm the male predominance in pediatric HD and show an association with EBV, especially in the youngest patients and with the mixed cellularity and interfollicular subtypes. Most, but not all, cases of pediatric HD can be subclassified by traditional criteria.

Inflammatory pseudotumor of lymph nodes: a study of 25 cases with emphasis on morphological heterogeneity

The clinicopathological and immunohistochemical findings in 25 cases of inflammatory pseudotumor of lymph nodes (IPT) are presented. The patients were 13 women and 12 men between 8 and 81 years of age. Clinically, symptoms of prior infection, fatigue, abdominal pain, weight loss, fever of unknown origin, pelvic inflammatory disease, or nausea and night sweats were obtained in 15 patients, whereas six patients presented with asymptomatic lymphadenopathy. In four additional patients, no clinical information was obtained. The involved nodes included cervical, supraclavicular, inguinal, mesenteric, and mediastinal lymph nodes. In two cases, there was synchronous involvement of separate lymph node groups (inguinal and cervical in one case and cervical and mediastinal in another case), whereas in a third patient there was synchronous involvement of the spleen and a paraaortic lymph node. Histologically, the lesions were characterized by a fibrosing/inflammatory process that showed marked heterogeneity and striking variation from case to case. Based on their histological features, the lesions could be classified into three different groups: Stage I was characterized by the appearance of single or multiple small foci containing a spindle cell proliferation admixed with a prominent inflammatory background, with complete preservation of the remainder of the nodal architecture; stage II was characterized by more diffuse involvement of the lymph node with a marked inflammatory response admixed with a prominent myofibroblastic proliferation leading to subtotal effacement of the nodal architecture, often with extension of the process beyond the capsule into perinodal fat; and stage III was characterized by almost complete replacement of the lymph node by diffuse sclerosis with scant residual inflammatory elements and total loss of the normal nodal architecture. Immunohistochemical studies in 20 cases showed a striking number of vimentin- and actin-positive myofibroblastic cells with moderate increase in CD20/CD45+ small lymphocytes and polyclonal plasma cells in the stage I lesions, the emergence of numerous CD68+ histiocytes admixed with lymphocytes, plasma cells, and abundant fibromyofibroblastic cells in the stage II lesions, and only few remaining scattered CD68+ histiocytes and fibroblasts in the stage III lesions. Our findings suggest that inflammatory pseudotumor of lymph node represents an evolving, dynamic process that may adopt different morphological appearances depending on its stage of evolution. Recognition of the various stages of this process may be of importance for differential diagnosis with other fibrosing/inflammatory conditions of lymph nodes.

Primary leiomyosarcomas of the lung: a clinicopathologic and immunohistochemical study of 18 cases

We studied 18 patients with primary malignant smooth muscle tumors of the lung (7 women and 11 men, 5-76 yr old, with a mean age of 50 yr). Lesions varied from 1.7 to 10 cm in greatest diameter. The tumors were classified as low (4 cases), intermediate (2), or high grade (12). Low-grade lesions were characterized by an orderly proliferation of fascicles of spindle cells that intersected at right angles and showed oval-to-spindle cells with cigar-shaped nuclei, minimal pleomorphism, and low mitotic activity, without hemorrhage or necrosis. Intermediate-grade lesions retained the fascicular configuration but showed increased cellularity with atypia and dense chromatin pattern, occasional pleomorphism, and mild increase in mitotic activity. High-grade lesions showed high cellularity, marked pleomorphism and atypia, frequent areas of hemorrhage and necrosis, and high mitotic activity. Immunohistochemical studies in 16 cases showed positive staining of tumor cells with smooth muscle actin in 12, desmin in 5, and coexpression of actin and/or desmin and keratin in 3. Six patients with low- and intermediate-grade lesions were alive and well from 2 to 12 years after diagnosis (mean follow-up time, 6 yr); 8 with high-grade lesions died of their tumors with widespread metastases from 1 to 24 months after diagnosis (median survival time, 5 mo). One patient whose tumor showed features of high-grade leiomyosarcoma was alive and well 12 years after surgery. Three patients with high-grade tumors were lost to follow-up. Our findings suggest that histologic grade may be the most reliable prognostic parameter for predicting clinical behavior in primary leiomyosarcoma of the lung and that smooth muscle actin is the most sensitive immunohistochemical marker for establishing the diagnosis in these tumors. Primary leiomyosarcoma should be considered in the differential diagnosis of pulmonary spindle cell neoplasms; histologic grading may be of value in the planning of therapy and assessment of prognosis for these lesions.

Hodgkin's disease and an extranodal marginal zone B-cell lymphoma in the small intestine: an unusual composite lymphoma

We describe a 74-year-old man who presented with multifocal small bowel lesions, a large mesenteric mass, and enlarged mesenteric lymph nodes. In each of the extranodal sites and in two of three regional lymph nodes, there were classic histologic features of marginal zone B-cell lymphoma with adjacent areas of Hodgkin's disease, mixed cellularity subtype. Immunophenotypic analysis in the areas of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue showed immunoreactivity for CD45RB and CD20 in the malignant small cell population. Conversely, the areas of Hodgkin's disease demonstrated positive immunoreactivity for CD15 and CD30 in the Reed-Sternberg cells and variants. Latent membrane protein for Epstein-Barr virus was also positive in the Reed-Sternberg cells and variants.

Olfactory neuroblastoma and other round cell lesions of the sinonasal region

Sixty-nine round cell lesions of the sinonasal region (22 olfactory neuroblastomas [ONBs], 17 malignant lymphomas, nine Ewing's sarcomas [ES], nine rhabdomyosarcomas, three sinonasal undifferentiated carcinomas, five malignant melanomas, and four pituitary adenomas) were studied in an attempt to define the differential diagnostic capabilities of antibody to MIC2 and bcl-2 in paraffin-embedded tissue in the distinction of these lesions. In addition, antibody to p53 was applied in each case to define the incidence of p53 positivity among these various tumor types. Each of the ES cases was MIC2 positive; each of the other cases was MIC2 negative. Positivity for bcl-2 was confined to two cases, one of them a malignant lymphoma (85% of cells positive) and one an ONB (5% of cells positive). Small numbers of scattered p53-positive cells appeared in the majority of cases studied, without regard for the specific tumor type; only a single case, a malignant lymphoma, showed a majority (approximately 90%) of p53-positive cells. These results indicate that the MIC2 antibody is a useful method by which to distinguish ES from a variety of other round cell lesions that may be encountered in the sinonasal region. The practical applications of antibody to bcl-2 and p53 seem to be much more limited; by contrast, neither bcl-2 positive cells nor abundant p53 cells identified by immunohistochemical analysis seemed to be frequent findings in any of the tumor types studied. Although ONBs have been included with the peripheral primitive neuroectodermal tumors for classification purposes, these tumors diverge from the ES/primitive neuroectodermal tumor family in that they do not seem to share either the MIC2 positivity or the t(11;22) chromosomal translocation that typify the ES/primitive neuroectodermal tumor family of lesions. Although bcl-2 positivity has been associated with a light microscopic finding of an unfavorable histologic pattern in retroperitoneal neuroblastomas, it does not seem that bcl-2 positivity in ONB will select for a clinically distinctive subset of patients.

Lymphoid changes of the nasopharyngeal and palatine tonsils that are indicative of human immunodeficiency virus infection. A clinicopathologic study of 12 cases

We report 12 cases in which the histomorphologic changes of the nasopharyngeal tonsils (adenoids) or palatine tonsils suggest infection with the human immunodeficiency virus (HIV). The patients included 10 men and two women, aged 20 to 42 years (median, 33 years). The clinical presentation included airway obstruction, pharyngitis, fever, and a tonsillar or adenoidal mass lesion. Histologic evaluation of the excised adenoids or tonsils in 10 of the cases demonstrated a spectrum of changes including florid follicular hyperplasia, follicle lysis, attenuated mantle zone, and the presence of multinucleated giant cells (MGC). The latter characteristically localized adjacent to the surface or tonsillar crypt epithelium. Two of the 12 cases showed marked lymphoid depletion with absent germinal centers, plasmacytosis, and stromal vascular proliferation. Immunohistochemical evaluation for HIV p24 core protein showed reactivity in 10 of 12 cases localized to follicular dendritic cell network (FDC), the MGC, scattered interfollicular lymphoid cells, and cells identified within the surface or crypt epithelium. Localization of viral RNA by in situ hybridization paralleled the HIV p24 immunohistochemical findings. Additional significant findings included the presence of both CD-68 and S-100 protein in the MGC and the presence of S-100 protein in dendritic cells. Other than HIV, no microorganisms were identified. At the time of presentation, eight patients were not known to be a risk for HIV infection, nor were they known to be HIV infected or suffering from AIDS. In these patients, HIV infection was suspected on the basis of the histologic changes seen in the resected tonsillar and adenoidal tissue. Serologic evaluation (by enzyme-linked immunosorbent assay), confirmed the presence of HIV infection. Our findings suggest the possibility of HIV dissemination through the upper aero-digestive tract mucosa via target cells, such as intraepithelial dendritic cells, submucosal macrophages, and T-lymphocytes. Subsequent presentation of viral antigens to the tonsillar and adenoidal lymphoid tissues results in enlargement of these structures that clinically may simulate a neoplastic proliferation but causes histomorphologic changes that are highly suspicious for HIV infection even in asymptomatic HIV-positive patients.

Replication of HIV-1 in dendritic cell-derived syncytia at the mucosal surface of the adenoid

Human immunodeficiency virus-type 1 (HIV-1) replicates actively in infected individuals, yet cells with intracellular depots of viral protein are observed only infrequently. Many cells expressing the HIV-1 Gag protein were detected at the surface of the nasopharyngeal tonsil or adenoid. This infected mucosal surface contained T cells and dendritic cells, two cell types that together support HIV-1 replication in culture. The infected cells were multinucleated syncytia and expressed the S100 and p55 dendritic cell markers. Eleven of the 13 specimens analyzed were from donors who did not have symptoms of acquired immunodeficiency syndrome (AIDS). The interaction of dendritic cells and T cells in mucosa may support HIV-1 replication, even in subclinical stages of infection.

Primary diffuse large B-cell lymphoma of the breast. A clinicopathologic study of 31 cases

Primary non-Hodgkin's lymphoma of the breast is a rare neoplasm for which survival data vary among the reported studies. Thirty-one cases of diffuse large B-cell lymphoma of the breast, which had been seen in consultation from 1973 to 1985 at our institution, were reviewed. This represents the largest number of lymphomas of this histologic subtype reported to date in the English literature. Histologic examination and immunophenotypic analysis were performed and the results were correlated with clinicopathologic data. The patient population consisted of 29 females and 2 males with a mean patient age of 58.2 years. At the time of diagnosis, 26 patients had unilateral involvement (16 left, 10 right), and 5 had bilateral disease. Mean tumor size was 3.8 cm. Histologically, all cases showed a diffuse large B-cell lymphoma as classified by the Revised European-American Classification of Lymphoid Neoplasms (R.E.A.L Classification). Immunophenotypic studies on paraffin sections confirmed a B-cell lineage in every case. The majority of patients received chemotherapy and/or radiation therapy. The median survival was 36 months, confirming that this neoplasm has a poor prognosis.

Lipid cell (steroid cell) tumor of the ovary: immunophenotype with analysis of potential pitfall due to endogenous biotin-like activity

Twenty-eight lipid cell (steroid cell) tumors of the ovary were studied by immunohistochemistry using an avidin-biotin complex detection system; 75% of tumors were vimentin positive, 46% were positive for cytokeratin (CAM5.2 antibody), 37% were positive with the cytokeratin cocktail AE1/AE3 and CK1, and 29% were positive for smooth muscle alpha-actin. Three tumors were positive for CD68 (KP-1), a histiocyte marker, and each of the following markers was positive in two cases: desmin, epithelial membrane antigen, neuron-specific enolase, and S-100 protein. All tumors tested were negative for chromogranin A, CD15 (Leu-M1), myoglobin, neurofilament protein, alpha-fetoprotein, carcinoembryonic antigen, and melanoma-associated antigen (HMB-45 antibody). Immunoreactivity for cytokeratins was usually focal, paranuclear, and globoid, while reactivity for actin and vimentin was diffuse and cytoplasmic. Based on these findings, melanomas and some carcinomas should be distinguishable from lipid cell tumors. However, the immunohistochemical profiles of smooth-muscle tumors, other gonadal stromal tumors (granulosa cell tumors, thecomas), and hepatocellular, renal cell, and adrenocortical carcinomas overlap with that of lipid cell tumors, and therefore these tumors may not be distinguishable from lipid cell tumors using this technique. In 10 cases (36%), negative controls exhibited weak to moderate nonspecific cytoplasmic staining. Evidence obtained using a biotin blocking kit, and a monoclonal antibody against biotin, suggests endogenous biotin-like reactivity as the source of the nonspecific staining.

Non-Hodgkin's lymphoma of the sinonasal tract. A clinicopathologic and immunophenotypic study of 120 cases

BACKGROUND

Non-Hodgkin's lymphomas (NHLs) of the sinonasal tract are uncommon neoplasms that can be morphologically difficult to distinguish from destructive nonneoplastic processes or other malignant neoplasms in this site.

METHODS

From the files of the Otolaryngic Tumor Registry-Armed Forces Institute of Pathology from 1965 to 1992, 120 cases of NHL involving the sinonasal tract were selected for which clinical records and paraffin-embedded tissue blocks were available. The histologic features and immunophenotypic findings of each patient were examined, and follow-up data were obtained for 66 (55%).

RESULTS

The ratio of males to females was 1.35:1, and the ages ranged from 3 to 94 years (median, 59 years). Sixty percent of the cases of NHL occurred in the patients' sixth to eighth decades of life. Clinical presentations varied according to histologic type. The low grade lymphomas presented with a nasal cavity or paranasal sinus mass associated with obstructive symptoms. The high grade lymphomas were more likely to present with aggressive signs and symptoms including nonhealing ulcer, cranial nerve manifestations, facial swelling, epistaxis, or pain. Of note, the high grade B-cell lymphomas tended to present with soft tissue or osseous destruction, particularly of the orbit with associated proptosis, whereas the T-cell lymphomas were associated with nasal septal perforation and/or destruction. Sites of disease included the nasal cavity, one or more paranasal sinuses, or multiple regions within the sinonasal tract. Of patients who received adequate follow-up, nodal and extranodal dissemination were identified in a limited number (n = 11). Nodal dissemination occurred in cervical and axillary lymph nodes. Extranodal sites of involvement included the larynx, skin, liver, uvula, kidney, breast, lacrimal gland, testis, and prostate gland. There was a wide spectrum of morphologic types of lymphoma, classified according to the Working Formulation. Immunophenotypic analysis on paraffin embedded tissue sections of all patients demonstrated a B-cell to T-cell ratio of 1.18:1. Treatment primarily included radiotherapy and chemotherapy. Follow-up information was available for 66 (55%) patients ranging from 1 to 16 years (median, 3 years). Of these 66 patients, 24 (36.4%) died of disease, 17 (25.7%) are alive without disease, 13 (19.7%) are alive with disease, and 12 (18.2%) are dead of unrelated or unknown causes.

CONCLUSIONS

Non-Hodgkin's lymphomas of the sinonasal tract are heterogeneous diseases that can be clinically aggressive. The frequency of these lymphomas in the United States cannot be estimated accurately because all of our cases were of histologic slides submitted for consultations. There appears, however, to be a slight B-cell predominance in this population that previously has been observed, unlike in South America and Asia where the majority of cases have a T-cell phenotype.

MIC2 detection in tumors of bone and adjacent soft tissues

The diagnosis of Ewing's sarcoma has been based classically in large part on the exclusion of other similar small round-cell tumors by light microscopic and histochemical criteria. This study was undertaken to explore the use of a recently developed immunohistochemical stain directed against the glycoprotein p30/32MIC2 antigen (the gene product of MIC2), as a diagnostic tool and as a probe for the examination of potential interrelationships among the putative members of the family of peripheral primitive neuroectodermal tumors. Fifty-six small round-cell tumors of bone were selected for study from the files of the Armed Forces Institute of Pathology and Rhode Island Hospital; all tissues had been formalin fixed and paraffin embedded. Nine of 10 Ewing's sarcomas were MIC2 positive, as were 2 of 3 atypical Ewing's sarcomas (small round-cell tumors that diverged from the classic pattern of Ewing's sarcoma by exhibiting a greater degree of cytologic atypia and pleomorphism), and 7 of 8 Askin tumors of the thoracopulmonary region. Ten of 11 mesenchymal chondrosarcomas, 1 primitive neuroectodermal tumor of bone, 10 small cell osteosarcomas, 10 malignant lymphomas, and 3 sarcomas of bone (not additionally subclassified) were negative. The finding of MIC2 positivity in the majority of Ewing's sarcomas and Askin tumors provides additional support for earlier proposals (based on a shared cytogenetic abnormality, among other criteria) that these lesions be considered members of the same family, the peripheral primitive neuroectodermal tumors. The present study, drawing on archival and current case material (including decalcified and undecalcified specimens), indicates that neither the specimen age nor the application of any of a variety of decalcification solutions appears to adversely influence MIC2 staining of paraffin-embedded tissues. This suggests that this antibody has use in retrospective and prospective studies. The rare occurrence of false negative (in the case of Ewing's sarcoma) and positive results in tumors other than peripheral primitive neuroectodermal tumors (as in 1 of the mesenchymal chondrosarcomas) suggests that MIC2 staining should not be relied on as the sole criterion for identification or exclusion of Ewing's sarcomas and related tumors.

The spectrum of immunohistochemical staining of small-cell lung carcinoma in specimens from transbronchial and open-lung biopsies

Immunohistochemistry is increasingly used as an aid in the diagnosis of small-cell lung carcinoma (SCLC). Previous studies have investigated immunohistochemical staining of SCLC with small numbers of antibodies, but few have examined large series with a broad panel of antibodies. For this reason, the authors examined the distribution and intensity of staining of 20 open-lung biopsy (OLB) and 21 transbronchial biopsy (TBB) specimens of SCLC with a panel of epithelial, neuroendocrine, and hormonal markers. Small-cell lung carcinoma stained most frequently with epithelial markers, followed by neuroendocrine and hormonal markers. Similar percentages of OLB and TBB specimens stained for keratin (100% each) and epithelial membrane antigen (100% and 95%, respectively). Unexpectedly, BER-EP4 stained 100% of OLB specimens. Chromogranin A was the most frequent neuroendocrine marker in OLB and TBB specimens (60% and 47%, respectively) followed by neuron-specific enolase (60% and 33%), Leu-7 (40% and 24%), and synaptophysin (5% and 19%). No neuroendocrine immunohistochemical reactivity was found in 24% of TBB specimens and 20% of OLB specimens. Bombesin was the most sensitive hormonal marker (45% of OLB specimens). These results show that keratin, epithelial membrane antigen, and BER-EP4 are reliable epithelial markers for SCLC in both TBB and OLB specimens. In addition, negative staining for neuroendocrine markers, because it can occur in as many as 25% of cases, should not deter the diagnosis of SCLC.

Epithelioid angiosarcoma of the adrenal glands. A clinicopathologic study of nine cases with a discussion of the implications of finding "epithelial-specific" markers

Adrenal epithelioid angiosarcomas (AEA) are rare neoplasms. We report the clinicopathologic features of nine cases of AEA. AEA occurred most frequently in the sixth and seventh decades of life (age range, 45-85 years; median, 60); five cases occurred in men and four in women. Presenting symptoms included abdominal mass with or without pain, weight loss, fever, and weakness. Two cases were asymptomatic; one was discovered during evaluation for other disease(s) and the other at autopsy. All neoplasms were nonfunctioning. Radiographic evaluation demonstrated suprarenal or retroperitoneal neoplasms ranging in size from 6 to 10 cm in greatest dimension. Histologically, the neoplasms were invasive, predominantly arranged in solid sheets or nests, and composed of epithelioid cells. Endothelial cell differentiation was suggested by the transition areas between dilated anastomotic vascular spaces and the sheet-like growth, the cytomorphologic similarity between the endothelial cells lining the discernible vascular spaces and those seen in the solid foci, and the presence of intracytoplasmic vacuolization occasionally containing red blood cells. Endothelial derivation was confirmed by immunohistochemistry including Factor VIII-related antigen (FVIII), CD-34 (hematopoetic progenitor cell antigen), and/or Ulex europaeus agglutinin-1 lectin immunoreactivity (UEA-1) and by ultrastructural findings, including rod-shaped microtubulated bodies and intracytoplasmic lumen formation. In addition, cytokeratin reactivity was seen in seven cases, and B72.3 (tumor-associated glycoprotein-72) reactivity was seen in six. Surgical resection was the treatment of choice, occasionally supplemented by chemotherapy. Three patients are presently alive, free of disease, at 13, 11, and 6 years following diagnosis. Three died with metastatic AEA of the lung, and three died of unrelated causes.

Extranodal sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) of the head and neck

We report 14 cases of extranodal sinus histiocytosis with massive lymphadenopathy involving a variety of head and neck sites. The patients ranged in age from 3 to 70 years (median, 43 years). Nine cases occurred in women and five occurred in men. The clinical presentation varied depending on the site of occurrence and included nasal obstruction, stridor, proptosis, ptosis, decreased visual acuity, facial pain or tenderness, cranial nerve deficits, mandibular tenderness, and mass lesions. Head and neck sites involved by disease included the nasal cavity, paranasal sinuses, nasopharynx, parotid gland, submandibular gland, larynx, temporal bone, infratemporal fossa, pterygoid fossa, meninges, and orbital region. The majority of patients presented with involvement of more than one site. Nodal involvement was identified in four patients. Special stains for microorganisms were negative. The sinus histiocytosis with massive lymphadenopathy cells demonstrated an immunophenotypic profile supporting derivation from macrophage/histiocytic lineage. Treatment varied and included surgical excision with or without adjuvant therapy (chemotherapy, radiotherapy) or steroids. Several patients required more extensive surgery as a result of extension of their disease to adjacent structures or due to recurrent disease. Twelve patients are alive and either free of disease or have persistent disease. Two patients died, one as a result of complications of disease.