Sinusoidal CD30-positive large B-cell lymphoma: a morphologic mimic of anaplastic large cell lymphoma

Diffuse large B-cell lymphomas, not otherwise specified, and emerging entities

Diffuse large B-cell lymphoma (DLBCL) is an aggressive and heterogenous group of diseases and the most common subtype of non-Hodgkin lymphoma. In the past decade, there has been an explosion in molecular profiling that has helped to identify subgroups and shared oncogenic driving mechanisms. Since the 2017 World Health Organization (WHO) classification, additional studies investigating these genomic abnormalities and phenotypic findings have been reported. Here we review these findings in DLBCL and address the proposed changes by the 2022 International Consensus Classification.

Diagnostic utility of programmed cell death ligand 1 (clone SP142) immunohistochemistry for malignant lymphoma and lymphoproliferative disorders: A brief review

The programmed cell death 1 (PD1)/PD1 ligand (PD-L1) axis plays an important role in tumor cell escape from immune control and has been most extensively investigated for therapeutic purposes. However, PD-L1 immunohistochemistry is still not used widely for diagnosis. We review the diagnostic utility of PD-L1 (by clone SP142) immunohistochemistry in large-cell lymphomas, mainly consisting of classic Hodgkin lymphoma (CHL) and diffuse large B-cell lymphoma (DLBCL). Neoplastic PD-L1 (nPD-L1) expression on Hodgkin and Reed-Sternberg cells is well-established among prototypic CHL. Of note, EBV+ CHL often poses a challenge for differential diagnosis from peripheral T-cell lymphoma with EBV+ non-malignant large B-cells; their distinction is based on the lack of PD-L1 expression on large B-cells in the latter. The nPD-L1 expression further provides a good diagnostic consensus for CHL with primary extranodal disease conceivably characterized by a combined pathogenesis of immune escape of tumor cells and immunodeficiency. Compared with CHL, the nPD-L1 expression rate is much lower in DLBCL, highlighting some specific subgroups of intravascular large B-cell lymphoma, primary mediastinal large B-cell lymphoma, and EBV+ DLBCL. They consist of nPD-L1-positive and -negative subgroups, but their clinicopathological significance remains to be elucidated. Microenvironmental PD-L1 positivity on immune cells may be associated with a favorable prognosis in extranodal DLBCL. PD-L1 (by SP142) immunohistochemistry has helped us to understand the immune biology of lymphoid neoplasms possibly related by immune escape and/or immunodeficiency. However, knowledge of these issues remains limited and should be clarified for diagnostic consensus in the future.

The clinicopathological and molecular features of sinusoidal large B-cell lymphoma

We report 17 cases of sinusoidal large B-cell lymphoma (SLBCL). Clinical, morphologic, immunophenotypic, and molecular features were detected and analyzed. All cases showed an obvious sinusoidal growth pattern, usually associated with residual atrophic lymphoid tissue. All tumors contained large pleomorphic lymphoid cells and one or more prominent nucleoli, with abundant amphophilic cytoplasms; 15/17 cases showed anaplastic morphologic features. The patient age ranged from 43 to 80 years (median 57 years), and 7 males and 10 females were included. Eleven of 15 (73.3%) patients had Ann Arbor stage III or IV disease, and 10/15 (66.6%) patients had an International Prognostic Index (IPI) score ≥3. Immunophenotypically, 16/17 (94.1%) cases displayed a nongerminal center B-cell (non-GCB) immunophenotype. Furthermore, 16/17 (94.1%) cases were positive for CD30, and p53 was expressed in 10/16 (62.5%) cases. In total, 12/14 (85.7%) cases expressed BCL2 and MYC simultaneously (double expression), and 11/14 (78.6%) cases showed PD-L1 positivity (6/11 had a PD-L1 tumor proportion score ≥50%). Cytogenetically, concurrent MYC and BCL2 and/or BCL6 abnormalities (break-apart or extra copy) were detected in 10/15 cases, and 7/13 (53.8%) cases harbored a PD-L1/L2 amplification. TP53 mutation was found in 7/13 (53.8%) cases by Sanger sequencing. Whole-exome and large-panel sequencing results revealed high mutation frequencies of TP53 (4/7), MYD88 (3/7), KMT2D (3/7), CREBBP (3/7), and PIM1 (3/7). Among the 13 patients with SLBCL treated with aggressive chemotherapy regimens, the median overall survival (OS) was 18 months, and the 2-year OS rate was 34.6%. The OS of patients with SLBCL was markedly worse than that of 35 control group patients with common diffuse large B-cell lymphoma (DLBCL) without sinusoidal features (P < 0.001). SLBCL may represent a specific type of DLBCL that has characteristic pathologic features. The cancer is aggressive in most clinical cases, and outcomes are poor. SLBCL and anaplastic DLBCL (A-DLBCL) have many overlapping clinicopathological and molecular features.

Anaplastic variant of diffuse large B-cell lymphoma: Reappraisal as a nodal disease with sinusoidal involvement

Anaplastic variant (av) of diffuse large B-cell lymphoma (DLBCL) is morphologically defined in the 2017 World Health Organization classification, but still an enigmatic disease in its clinicopathologic distinctiveness, posing the differential diagnostic problem from gray zone lymphoma (GZL) and classic Hodgkin lymphoma (cHL). Thirty-one cases previously diagnosed as avDLBCL were reassessed. Of these, 27 (87%) and 4 (13%) were node-based and extranodal diseases, respectively. They were further reclassified into nodal avDLBCL (n = 18), nodal CD30+ DLBCL with T-cell/histiocyte-rich large B-cell lymphoma-like features (CD30+ DLBCL-THRLBCL) (n = 6), GZL with features intermediate between DLBCL and cHL (n = 3) and CD30+ extranodal DLBCL, NOS (n = 4). The nodal avDLBCL cases had a sheet-like proliferation of large cells and/or Hodgkin/Reed-Sternberg (HRS)-like cells in 12 (67%) notably with a sinusoidal pattern in 16 (89%). They showed an expression of CD20 and/or CD79a in all and CD30 in 15 of 18. All of them were negative for PD-L1 on tumor cells, although HRS-like cells showed negativity or partial loss of other B-cell markers to varying degrees. The present study highlighted the distinctiveness of the nodal avDLBCL with sinusoidal pattern, but without neoplastic PD-L1 expression, which provide refined diagnostic criteria for a more precise pathologic and clinical characterization of this disease.

Renal hypoplasia can be the cause of membranous nephropathy-like lesions

BACKGROUND

Renal hypoplasia (RH) is the most common cause of chronic kidney disease in children. In cases of RH, proteinuria is often induced by glomerular hypertrophy and hyperfiltration that is commonly associated with focal segmental glomerulosclerosis. This study reports the first case series of a possible association between RH and membranous nephropathy (MN).

METHODS

Of the 168 children with RH who visited our department between 1999 and 2017, five with overt proteinuria (≥ 1 g/gCr) underwent renal biopsy. We retrospectively reviewed the medical charts and analyzed biopsy specimens using light microscopy (LM), immunofluorescence (IF), and electron microscopy.

RESULTS

The five children (four boys and one girl) had a median age of 5.5 years at the time of renal biopsy. The median proteinuria was 4.23 g/gCr (range 1.46-14.25), median serum albumin, 2.9 g/dL (range 2.3-3.7), and median estimated glomerular filtration rate, 59.7 mL/min/1.73 m² (range 36.7-103.6). LM showed segmental spike formation and mesangial hypercellularity and IF study showed segmental granular immunoglobulin G (IgG) staining (IgG1 and IgG3 dominant) along the capillary loops in all five patients. Electron-dense deposits were observed in the subepithelial and mesangial areas. Thus, the pathological studies showed MN-like lesions in all patients.

CONCLUSION

Our study suggests that RH can be the cause of MN-like lesions.

Anaplastic variant of diffuse large B-cell lymphoma with hallmark cell appearance: Two cases highlighting a broad diversity in the diagnostics

The anaplastic variant of diffuse large B-cell lymphoma (A-DLBCL) is morphologically defined but remains an enigmatic disease in its clinicopathologic distinctiveness. Here, we report two cases involving Japanese women aged 59 years, both with A-DLBCL with the hallmark cell appearance and both indistinguishable from common and giant cell-rich patterns, respectively, of anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma. Case 1 was immunohistochemically positive for CD20, CD79a and OCT-2 but not for the other pan-B-cell markers, CD30 and ALK. Case 2 showed CD20 and CD30 positivity for 50% and 20% of tumor cells in addition to strong expression of p53 and MYC. Both were positive for fascin without Epstein-Barr virus association. Our cases provide additional support for the earlier reports that A-DLBCL exhibits clinicopathologic features distinct from ordinal diffuse large B-cell lymphoma (DLBCL), and documented its broader morphologic diversity than previously recognized. They also shed light on the unique feature of absent expression of pan-B-cell markers except for CD20 and CD79a, suggesting that A-DLBCL may biologically mimic a gray zone or intermediate lymphoma between DLBCL and classic Hodgkin lymphoma.

Sinusoidal CD30+ diffuse large B-cell lymphoma can masquerade as anaplastic large cell lymphoma in pediatric posttransplant lymphoproliferative disorders

Posttransplant lymphoproliferative disorder (PTLD) is a known complication of solid organ transplantation. Diffuse large B-cell lymphoma (DLBCL) is frequently seen in this setting. However, CD30+ DLBCL with sinusoidal pattern of involvement has not been reported in pediatric PTLD. We are reporting a 9-year-old female child presented with diffuse lymphadenopathy postheart transplantation. The pattern of involvement was suggestive of anaplastic large cell lymphoma, but the malignant cells were positive for B-cell markers and negative for anaplastic lymphoma kinase. The patient was treated aggressively with multiagent chemotherapy and rituximab. Accurate diagnosis in PTLD is paramount in making management decisions.

An Epstein-Barr virus-positive classical Hodgkin lymphoma with exclusive sinusoidal growth pattern: An unusual morphologic variant

Classical Hodgkin lymphoma (cHL) typically involves lymph node parenchyma, and a case with Hodgkin cells confined within nodal sinusoids is extremely rare. Herein we report a case of cHL with a sinusoidal growth pattern. This 15-year old patient presented with B symptoms and was found to have bilateral cervical lymphadenopathy and an anterior mediastinal mass. Biopsy of a cervical lymph node demonstrated cohesive clusters of Reed-Sternberg (RS)-like cells suggestive of sinusoidal growth with an extrasinusoidal mixed inflammatory cell infiltrate characteristic of the microenvironment seen in cHL. The RS cells/variants were positive for CD30 and CD15, and showed down-regulation of B-cell program and CD45, an immunophenotypic profile consistent with cHL. The sinusoidal growth pattern was also highlighted by EBV staining. To the best of our knowledge, this is the first case of EBV-positive cHL that displays a sinusoidal growth pattern. The patient was treated with children's high risk cHL chemotherapy protocol and responded well.

Primary effusion lymphoma involving cerebrospinal fluid, deep cervical lymph nodes and adenoids. Report of a case supporting the lymphatic connection between brain and lymph nodes

We describe an unusual presentation of primary effusion lymphoma in CSF of a 45-year-old HIV-positive man, with no evidence of involvement of pleural, peritoneal or pericardial cavities. Cytologic examination and flow cytometric analysis suggested the diagnosis, eventually made in an excised deep cervical lymph node, in which the neoplastic cells involved selectively the sinuses. This case represents the fifth reported example of CSF involvement by this type of lymphoma, and supports the alleged connection between CSF and cervical lymph nodes via lymphatic vessels. Interestingly, review of an adenoidectomy specimen obtained 9 months before presentation for nonspecific complaints showed rare clusters of neoplastic cells involving surface epithelium and chorium, a finding that might represent a homing mechanism and implies an asymptomatic, occult phase of lymphoma development.

A Rare Case of Anaplastic Variant of Diffuse Large B-Cell Lymphoma Presenting as a Lung Primary

Primary pulmonary lymphoma is an uncommon neoplastic disorder representing approximately 0.5% to 1% of primary pulmonary malignancies. The vast majority are of low-grade, mucosa-associated lymphoid tissue type. Primary diffuse large B-cell lymphoma of the lung is rare, though cases of the centroblastic and immunoblastic variants have been described. We present herein an interesting case of an 80-year-old man who presented with both respiratory and constitutional symptoms and was found to have a 4.5 cm left hilar mass with bilateral hilar and mediastinal lymphadenopathy on imaging. Endobronchial biopsy revealed an aggressive large cell lymphoma, with scattered large, bizarre-shaped nuclei resembling Reed–Sternberg cells, positive for CD20, PAX5, CD30, and MUM-1, consistent with an anaplastic variant of diffuse large B-cell lymphoma. Imaging showed no evidence of extrathoracic disease. Standard treatment with cyclophosphamide/vincristine/prednisone and rituximab resulted in significant clinical and radiological response and the patient remains in remission 21 months later. To the best of our knowledge, this modified Ann Arbor stage II2E primary pulmonary lymphoma, is the first description in the English literature of anaplastic variant of diffuse large B-cell lymphoma presenting as a lung primary.

Detection of Epstein-Barr virus DNA and expression of CD30 antigen in primary anaplastic diffuse large B-cell lymphoma of the brain

We describe a case of primary anaplastic diffuse large-cell lymphoma arising in the central nervous system (CNS). Primary CD30-positive anaplastic diffuse large B-cell lymphoma of the brain is very rarely reported. Given that this tumor is immunohistochemically heterogeneous, polymerase chain reaction (PCR) and Epstein-Barr virus (EBV) analysis of tumor DNA are essential techniques for early and accurate histological diagnosis in these CD30-positive cerebral lymphoma cases. We report an early CD30- and EBV-positive anaplastic diffuse large B-cell lymphoma in the CNS that was diagnosed not only from the immunohistochemical study and MRI findings, but also from the genotype confirmations. This tumor was documented to have EBV episomes of monoclonal origin by PCR analysis of immunoglobulin gene rearrangement.

CD30-positive anaplastic variant diffuse large B cell lymphoma: a rare case presented with cutaneous involvement

A 67-year-old man suffered from a left cervical lymph node swelling and tenderness. Biopsy of the cervical lymph node showed pleomorphic large cells containing large atypical nuclei. Immunohistochemical stains of these cells were positive for CD30, but negative for CD3 and CD20. After the biopsy, his left cervical skin was ulcerated. Biopsy of the left cervical skin was performed. Large pleomorphic cells with constricted nuclei and Reed-Sternberg-like cells existed in the dermis and epidermis. Immunohistochemical stains of the former cells were positive for CD30, CD45 and PAX5, but negative for CD3, CD10, CD20, CD15, Bcl-2, EBER ISH, EMA and ALK. He was diagnosed with diffuse large B cell lymphoma, anaplastic variant. He achieved complete remission with CHOP chemotherapy. CD30-positive DLBCL, anaplastic variant is a rare B cell lymphoma. Most of the patients presented with primary nodal disease, and skin involvement of lymphoma is very rare. This is the report of a rare case of CD30-positive DLBCL, anaplastic variant, with both nodal and skin lesions.

Gray zones around diffuse large B cell lymphoma. Conclusions based on the workshop of the XIV meeting of the European Association for Hematopathology and the Society of Hematopathology in Bordeaux, France

The term "gray-zone" lymphoma has been used to denote a group of lymphomas with overlapping histological, biological, and clinical features between various types of lymphomas. It has been used in the context of Hodgkin lymphomas (HL) and non-Hodgkin lymphomas (NHL), including classical HL (CHL), and primary mediastinal large B cell lymphoma, cases with overlapping features between nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B cell lymphoma, CHL, and Epstein-Barr-virus-positive lymphoproliferative disorders, and peripheral T cell lymphomas simulating CHL. A second group of gray-zone lymphomas includes B cell NHL with intermediate features between diffuse large B cell lymphoma and classical Burkitt lymphoma. In order to review controversial issues in gray-zone lymphomas, a joint Workshop of the European Association for Hematopathology and the Society for Hematopathology was held in Bordeaux, France, in September 2008. The panel members reviewed and discussed 145 submitted cases and reached consensus diagnoses. This Workshop summary is focused on the most controversial aspects of gray-zone lymphomas and describes the panel's proposals regarding diagnostic criteria, terminology, and new prognostic and diagnostic parameters.

Diffuse large B-cell lymphoma with Homer-Wright rosettes, sinusoidal growth pattern, and CD30 expression: a possible overlap between microvillous lymphomas and sinusoidal CD30-positive large B-cell lymphomas

Rosette formation is an unusual finding in malignant lymphomas. We herein report another case of a diffuse large B-cell lymphoma (DLBCL) with ultrastructural evidence of cellular projections, sinusoidal growth pattern, and strong CD30 expression. A literature review of the DLBCL cases showing all these features was also performed.

Application of Immunohistochemistry in the Diagnosis of Non-Hodgkin and Hodgkin Lymphoma

Context.—Beginning with the immunologic classifications of Lukes and Collins and Kiel and culminating in the Revised European-American Lymphoma and World Health Organization classifications, the diagnosis of lymphoid tumors relies heavily on the determination of cell lineage, maturation, and function, based on antigen expression in addition to morphology and clinical features. Technologic advances in immunology, antibody production, genetic analysis, cloning, and the identification of new genes and proteins by microarray and proteomics have provided pathologists with many antibodies to use in routine diagnosis.

Objective.—To provide guidance to the practicing pathologist in the appropriate selection of an antibody panel for the diagnosis of lymphoma based on morphology and relevant clinical data and to avoid pitfalls in the interpretation of immunohistochemical data. Attention is given to some of the newer antibodies, particularly against transcription factors, that are diagnostically and prognostically useful.

Data Sources.—The information presented in this article is based on review of the literature using the OVID database (Ovid MEDLINE 1950 to present with daily update) and 20 years of experience in diagnostic hematopathology.

Conclusions.—Immunophenotyping is required for the diagnosis and classification of lymphoid malignancies. Many paraffin-reactive antibodies are available to the pathologist but most are not specific. To avoid diagnostic pitfalls, interpretation of marker studies must be based on a panel and knowledge of a particular antigen's expression in normal, reactive, and neoplastic conditions.

Primary gastric Hodgkin's lymphoma expressing a B-Cell profile including Oct-2 and Bob-1 proteins

Classic Hodgkin's lymphoma (cHL) most often involves lymph nodes, and gastric involvement is rare. Hodgkin's and Reed-Sternberg (H-RS) cells in cHL are known to often lack expression of several B-lineage markers, such as CD20, CD79a, Oct-2, and Bob-1. We present an extremely rare case of mixed-cellularity cHL in the stomach in which expression of these B-cells was detected immunohistochemically. The patient was an 83-year-old Japanese woman who developed a sensation of abdominal fullness and appetite loss. Endoscopic and abdominal computed tomography examinations revealed a gastric ulcer lesion and swelling of para-aortic lymph nodes, respectively. A subtotal gastrectomy was performed, and the histopathologic diagnosis was established as a typical cHL compatible with stomach origin. The patient underwent postoperative chemotherapy of 3 cycles of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) and has since been in complete remission. Immunohistochemically, the H-RS cells in the cHL were positive not only for CD30 but also for CD20, CD79a, Oct-2, and Bob-1, whereas they were negative for CD3, CD15, CD45, EMA, and ALK1. Our patient may have had an intermediate cHL disease overlapping that of non-Hodgkin's peripheral B-cell lymphoma, possibly reflecting derivation from germinal-center B-cells.

Anaplastic large cell lymphoma: a flow cytometric analysis of 29 cases

We report our experience with flow cytometric (FC) analysis of 29 cases of anaplastic large cell lymphoma (ALCL). Morphologic analysis of processed cytocentrifuged preparations demonstrated neoplastic cells in 28 cases. In 25 of these, an aberrant lymphoid population was detected by FC analysis. The majority showed high orthogonal light scatter, similar to monocytes or granulocytes. Of the antigens CD2, CD3, CD4, CD5, and CD7, 5 cases expressed 1, 8 expressed 2, 6 expressed 3, 3 expressed 4, and 3 expressed all 5. CD4 was expressed most commonly (20/25 [80%]), followed by CD2 (18/25 [72%]), CD3 (10/25 [40%]), and CD5 and CD7 (8/25 [32%] each). CD45 was expressed in 23 of 25 cases and CD13 in 7 of 9. Of 21 cases, 13 were anaplastic lymphoma kinase (ALK)+, all of which were CD4+, vs 5 of 8 ALK - cases (P = .042). Most ALCLs can be detected and characterized by multiparameter FC analysis. However, light scatter gating on typical lymphoid regions may yield false-negative results in a substantial number of cases.

Primary Cutaneous CD30+ Large Cell B-Cell Lymphoma

BACKGROUND

White CD30 expression is described in extracutaneous diffuse large B-cell lymphomas, a primary cutaneous B-cell lymphoma (PCBCL) equivalent is not well defined.

METHODS

Between June 1999 and July 2002 the authors encountered 10 patients with CD30+ PCBCLs of the large cell type.

RESULTS

The patients comprised seven women and three men; five patients were over 80 years of age, all except one presenting with solitary plaques. With the exception of one death from myocardial infarction and one recurrence, all patients are well at a mean follow-up of 23.4 months. Skin biopsies showed a background of T-cell-rich reactive lymphoid hyperplasia in 7 of 10 patients, with variable granulomatous inflammation in 5 cases. The neoplastic large cells were immunoblastic in appearance. In four patients the infiltrate was dominated by large cells. In the remaining patients the reactive infiltrate defined the dominant cell population. The neoplastic cells expressed CD20, CD30, CD43, and BCL-2. In two cases associated with methotrexate therapy, Epstein-Barr virus expression was observed amid the neoplastic cell populace.

CONCLUSIONS

CD30+ PCBCL is a distinctive form of B-cell lymphoma presenting in elderly patients and can be associated with a very good prognosis. In some patients the intensity of reactive inflammation obscures the diagnosis. In the authors' experience almost a third of the cases were associated with Epstein-Barr virus infection and methotrexate therapy, suggesting a distinctive association.

Aggressive B-cell lymphomas: a review based on the workshop of the XI Meeting of the European Association for Haematopathology

The generic term aggressive B-cell lymphoma includes a variety of entities, each with particular diagnostic and therapeutic issues. To define these entities better and to help confront such issues, a workshop was organized by the European Association of Haematopathology (EAHP) and the Society of Haematology during the XI Meeting of the EAHP, held in Italy in May 2002. Participants were asked to submit cases under various categories and all cases submitted were examined and reviewed by the panel members. The panel's diagnoses formed the basis for discussion at the workshop and a limited number of cases were selected to be presented in more detail and discussed during the workshop. After the workshop the panel met again to discuss the outcome, summarized in this report, which describes the panel's proposals regarding diagnostic criteria, terminology, the definition of new entities and evaluation of biological differential and new prognostic parameters.

A unique atrial primary cardiac lymphoma mimicking myxoma presenting with embolic stroke: a case report

An immunocompetent 29-year-old male presented with an embolic stroke from an unusual primary cardiac lymphoma. The cardiac lesion consisted of a polypoid, left atrial, mural fibrin thrombus with anaplastic tumor cells lining the surface of the clot. Histologic, immunophenotypic, and molecular characterizations were consistent with a diagnosis of CD30+ large B-cell lymphoma with anaplastic cytology. While tumor emboli from invasive primary cardiac lymphomas have been reported, this noninvasive fibrin thrombus-associated lymphoma appears to be unique and previously unreported.

Rapid immunohistochemistry for cytokeratin in the intraoperative evaluation of sentinel lymph nodes for metastatic breast carcinoma

The sensitivity and specificity of detecting metastatic breast carcinoma in sentinel lymph nodes using a rapid immunohistochemistry technique was determined and compared with methods currently used at the authors' institution. At the time of intraoperative consultation, after routine diagnostic touch preparations and frozen sections were prepared, 6-microm frozen sections of 72 sentinel lymph nodes from 32 patients with breast carcinoma were placed on plus slides, fixed in cold acetone for 2 or 3 minutes, and stored at -70 degrees C. These sections were immunostained with a prediluted broad-spectrum anticytokeratin monoclonal antibody coupled to an inert polymer with horseradish peroxidase (DAKO EPOS). Slides were ready for interpretation within 16 minutes and were scored as positive, negative, or equivocal for metastatic carcinoma. Results were compared with those of the intraoperative touch preparations and frozen sections and with paraffin-embedded, hematoxylin and eosin-stained, and AE1/AE3 immunostained permanent sections. Fourteen (19%) sentinel lymph nodes were positive for metastatic carcinoma in 13 patients. All methods tested were 100% specific. The rapid immunohistochemistry method was the least sensitive (57% sensitivity) of all methods used to detect metastasis. Routine diagnostic touch preparations, frozen sections, and permanent sections had sensitivities of 69%, 86%, and 100% respectively. In conclusion, this rapid immunohistochemistry method would not be helpful in intraoperative assessment of sentinel lymph nodes in breast cancer patients due to its low sensitivity.

Pathological examination of sentinel lymph node in breast cancer: potential problems and possible solutions

Sentinel lymph node (SLN) biopsy has emerged during the last few years as a viable option for staging the axilla in the treatment of breast carcinoma. This procedure can potentially identify patients who would be helped by full axillary lymph node dissection (the SLN-positive cases), and those who would not (the SLN-negative cases). Review of the literature confirms the promise of SLN; however, the possible problems in the pathological handling of SLN, including the microscopic misinterpretation of benign structures and "spurious" immunohistochemical staining, need wider recognition.

CD79: a review

CD79 is composed of CD79a and CD79b components expressed almost exclusively on B cells and B-cell neoplasms. CD79a and CD79b expression precedes immunoglobulin (Ig) heavy-chain gene rearrangement and CD20 expression during B-cell ontogeny and disappears later than CD20 in the late (plasma cell) stage of B-cell differentiation. Therefore, antibodies to CD79a and CD79b are useful in the differential diagnosis of B-cell neoplasms from T-cell neoplasms or myeloid neoplasms, or L and H lymphocyte predominance Hodgkin's lymphoma from classic Hodgkin's lymphoma. In addition, CD79a and CD79b antibodies are useful markers in the diagnosis of precursor B-acute lymphoblastic leukemia (pre-B-ALL) because many of these tumors are negative for other B-cell markers, such as CD20 and CD45RA. Furthermore, for B-cell neoplasms, wherein CD20 expression is aberrantly lost, such as in diffuse large B-cell lymphoma, or for B-cell neoplasms after CD20-antibody therapy, CD79a may be used as a first-line B-cell marker for the diagnosis. In this review, the authors discuss the molecular biology of CD79 and the frequency and usefulness of CD79 expression in these neoplasms.