CD7+ and CD56+ myeloid/natural killer cell precursor acute leukemia: a distinct hematolymphoid disease entity

The disease spectrum of natural killer (NK) cell leukemias and lymphomas has recently been expanding with the continuing evolution in diagnostic concepts. We describe here seven cases of acute leukemia of conceivable myeloid and NK cell precursor phenotype in six men and one woman varying from 19 to 59 years of age (median, 46 years). Striking extramedullary involvement was evident at initial presentation, with peripheral lymphadenopathy and/or mediastinal masses. Two lacked any leukemic cells in the bone marrow at diagnosis. Using cytochemical myeloperoxidase staining, less than 3% of the leukemic cells showed positive reactivity. However, expression of CD7, CD33, CD34, CD56, and frequently HLA-DR, but not other NK, T-cell, and B-cell markers was observed. Cytoplasmic CD3 was detected in three of the cases by flow cytometry and in six by Northern blotting, suggesting an origin from common progenitors between the NK cell and myeloid lineages. All but one presented germline configurations of the T-cell receptor beta and gamma chain genes and Ig heavy chain gene. With regard to morphology, the cells were generally L2-shaped, with variation in cell size, round to moderately irregular nuclei and prominent nucleoli, pale cytoplasm, and a lack of azurophilic granules. Histopathologic examination of biopsied specimens of extramedullary tumors showed a lymphoblast-like morphology, implying the differential diagnostic problem from lymphoblastic lymphomas, especially in cases lacking bone marrow involvement. Three patients were successfully treated with chemotherapy for acute myeloid leukemia (AML), whereas three other patients proved refractory to chemotherapeutic regimens for lymphoid malignancies, although two responded to subsequent AML chemotherapy. However, despite intensive chemotherapy, including allogeneic bone marrow transplantation, most persued fatal courses within 41 months. These data suggested that the CD7+ and CD56+ myeloid/NK cell precursor acute leukemia might constitute a distinct biologic and clinical disease entity. Its recognition appears to be particularly important for the clinicopathologic evaluation of CD56+ hematolymphoid malignancies and the development of therapeutic approaches to such disease.

Vascular intimal carcinomatosis: an autopsy case of unusual form of pulmonary metastasis of transitional cell carcinoma

A 44-year-old woman with an unusual form of pulmonary metastasis is described. She presented with pulmonary thrombosis and clinical signs of disseminated intravascular coagulation (DIC) and died of cerebral hemorrhage. The autopsy study revealed transitional cell carcinoma of the left renal pelvis with pulmonary thrombosis in the large arteries. The intima of the vessels were intact on gross inspection except where the thrombi adhered to. The thrombi contained no tumor cells. However, microscopic examination identified that the metastatic carcinoma diffusely replaced the endothelium and proliferated on to the intimal surface without invasion of the wall and metastatic nodules in the parenchyma. Other examined organs had neither primary nor metastatic tumors, except for microscopic metastasis to the inferior vena cava. To date, this pattern of metastasis has not been noted in previous literature. This condition was designated as being vascular intimal carcinomatosis because of its characteristic manner of tumor proliferation on vascular intima.

Sarcoid-like reaction in the regional lymph nodes and spleen in gastric carcinoma: a clinicopathologic study of five cases

To clarify the occurrence of sarcoid-like reaction in the spleen of the gastric carcinoma patients, 100 consecutive specimens from gastrosplenectomy were examined. Sarcoid-like reaction was observed in the lymph nodes of 13 cases (13%) and the spleen of five cases (5%). All cases of the latter group were included in the former one. None of them showed any symptoms or signs indicative of systemic sarcoidosis. It seems that the cases with sarcoid-like reaction in the spleen ocurred more frequently in an advanced stage of the gastric cancer than those without this phenomenon. Epithelioid cell granulomas (EPGs) appeared to arise in the periarteriolar lymphoid sheaths of the spleen histologically, but were never found in red pulp or germinal centers. They were composed of groups of epithelioid cells and accompanied by the small lymphocytes and plasma cells. In three cases, scattered eosinophils were also observed among the epithelioid cells. Immunohistochemically, the majority of the intragranulomatous small lymphocytes had T-cell phenotype, while B-cells formed only the minor cellular population. None of the 13 cases contained EPGs in the primary tumor. Our study indicates that sarcoid-like reaction in the spleen is possibly not such a rare phenomenon in the gastric cancer as previously considered and more frequently seen in the advanced stage of the gastric cancer. Sarcoid-like reactions of the regional lymph nodes were more frequently seen in the patients with EPGs in the spleen than in those without. We also suggest that the incidence of sarcoid-like reactions in the spleen is closely related to those in pancreaticosplenic nodes and/or nodes of the hilus of the spleen.

A nodal gamma/delta T-cell lymphoma with an association of Epstein-Barr virus

The postthymic gamma/delta T-cell lymphoma is rare, and most occur as extranodal tumors, e.g., in hepatosplenic or cutaneous forms. We here report an unusual nodal case that initially presented as a T-zone lymphoma. The neoplasm recurred as systemic lymphadenopathy 25 months after complete remission with terminal high-grade transformation. Phenotypic analysis showed CD1-, CD2+, CD3+, CD4-, CD5-, CD7+, CD8+, CD10-, CD16-, CD19-, CD20-, CD21-, CD25-, CD56-, CD57-, T-cell receptor (TCR) alpha/beta antigens negative, TCR gamma/delta antigens positive, and an HLA-DR+ phenotype. Cytogenetic studies showed clonal chromosomal translocations involving chromosomes 1, 5, 6, 8, 15, and X in eight of 15 cells; t(X;5;1)(q13;q13;p22) and t(6;15;8)(p22;q26;q13). Genotypic analysis showed the same clone, characterized by the TCR gamma-chain gene rearrangement pattern, to be present in both initial and recurrent tumors. The lymphoma cells were also demonstrated to express the latent membrane protein-1 by immunohistochemistry and EBV-encoded small RNAs by in situ hybridization. Southern blot analysis using the probe of the terminal repeat demonstrated incorporation of multiple copies of EBV in the recurrent tumor. However, the initial lesion, which contained a smaller number of EBV-positive cells, showed no such evidence of clonal proliferation. These data suggest that EBV may be associated with high-grade transformation, although its exact role in lymphomagenesis remains uncertain. The present study also adds to our understanding of the clinicopathologic spectrum of gamma/delta T-cell neoplasia.

Immunostaining of PRAD1/cyclin D1 protein as a marker for the diagnosis of mantle cell lymphoma

The overexpression of PRAD1/cyclin D1 gene activated by the 11q13 translocation and its molecular counterpart BCL-1 rearrangement is frequently associated with mantle cell lymphomas (MCLs). Recently, we produced a monoclonal antibody, 5D4, against the PRAD1/cyclin D1 product, and demonstrated that the positive nuclear staining by this antibody correlates with PRAD1/cyclin D1 mRNA overexpression in MCLs. In the present study, we have immunohistochemically examined the cyclin D1 protein in a large series of 315 malignant lymphomas including 39 MCLs on paraffin sections. The nuclear positive pattern was found in 35 (90%) of 39 MCLs with an exceptional case of immunocytoma among the B-cell lymphomas examined. In the other cases, the positivity was absent or appeared to lie within the cytoplasm without nuclear staining. We therefore propose that the immunolocalization of cyclin D1 protein is an essential marker for the definite diagnosis of MCL.

Malignant lymphoma in patients with rheumatic diseases other than Sjögren's syndrome: a clinicopathologic study of five cases and a review of the Japanese literature

We conducted clinicopathologic and immunohistochemical analysis of five patients with malignant lymphoma complicating rheumatic diseases other than Sjögren's syndrome, and reviewed 26 cases of similar lesions reported in the Japanese literature over a 17-year period. All five patients were women ranging in age from 31 to 74 years (mean 55 years). Two of them fulfilled the diagnostic criteria for systemic lupus erythematosus, two for dermatomyositis and one for progressive systemic sclerosis. The use of immunosuppressive drugs before the onset of malignant lymphoma was recorded in four patients. All the biopsied or resected specimens showed non-Hodgkin's lymphoma of B-cell phenotype. Three were nodal in origin (one diffuse mixed, one diffuse large cell and one immunoblastic) and two were extranodal (one low-grade B-cell lymphoma of mucosa-associated lymphoid tissue and one diffuse large cell). In three of four cases examined, Epstein-Barr virus-encoded small RNAs were identified in a small to large number of the lymphoma cells by in situ hybridization. Our study showed that the clinicopathological features of malignant lymphomas complicating rheumatic disease in Japan were similar to those in England and the USA. Furthermore, our findings suggested no evidence for a causative association between iatrogenic immunosuppression due to methotrexate therapy and the development of EBV-related lymphoid neoplasms.

CD30-positive anaplastic large cell lymphoma in childhood: expression of p80npm/alk and absence of Epstein-Barr virus

CD30(+)-anaplastic large cell lymphoma (ALCL) is a distinct clinicopathologic entity of non-Hodgkin's lymphoma that is immunologically heterogeneous. Bimodal age distribution, a nonrandom chromosome abnormality [t(2;5)(p23;q35)] that produces a chimeric protein p80npm/alk, and a variable (5-47%) association with Epstein-Barr virus (EBV) have been reported. We reviewed 36 cases of ALCL (19 were children < 20 yr and 17 were adults) by focusing on the presence or absence of p80npm/alk protein and EBV. Immunophenotyping studies were performed on frozen and/or paraffin sections before initiation of chemotherapy. The p80 protein was immunohistochemically examined, and EBV-encoded RNA transcripts were detected by in situ hybridization. Among 19 cases in children, 13 cases had a T-cell and 6 cases had a null-cell phenotype. p80 Was detected in 16 (84.2%) of 19 cases in children and 3 (17.6%) of 17 cases in adults. All of the 19 cases of p80-positive ALCL were positive for epithelial membrane antigen, regardless of age. EBV genome was not detected in any of 19 cases in children and in only 2 of 15 cases in adults. ALCL in childhood seems to constitute a homogeneous entity characterized by expression of p80 and absence of EBV. The association of EBV is also infrequent in adult ALCL among Japanese patients.

Clinicopathologic study of nasal T/NK-cell lymphoma among the Japanese

A high prevalence of nasal lymphoma expressing a T- or natural killer (NK)-cell phenotype (NTCL) with frequent association of Epstein-Barr virus (EBV) has been indicated in Asians. To characterize NTCL among the Japanese, the clinicopathologic features of 32 cases were evaluated and the cases were also analyzed for EBV-RNA using an ISH method. Morphologically, 31 cases were identified by atypical pleomorphic lymphoid infiltrates with polymorphous, angicentric, and necrotic features. Their lymphoma cells ranged in size from small to large and were mixed in varying proportion from case to case. The other one case showed a monomorphic 'blastic' appearance. EBV-encoded small RNA (EBER) was detected in the neoplastic cells of 27 of the 32 cases examined. In the five EBV-negative cases, one was the 'blastic' type. Clonal T-cell receptor gene rearrangement was detected in none of seven cases examined. The patients had a median follow-up of 9 months (range, 1 month to 14 years and 11 months). The Kaplan-Meier estimate of overall survival was 49% at 5 years, correlating with clinical stage. These data support the concept that most cases of NTCL are identified as tumors with T/NK-cell characteristics and EBV association, distinctly different from other peripheral T-cell lymphomas. Furthermore, the one case of an EBV-negative 'blastic' variant appears not to fit well into the pleomorphic category but more closely resembles the pathologic features of extranasal angiocentric lymphoma with lymphoblastoid appearance. This study also showed no clear difference in clinical aspects other than the original site or in prognosis, between NTCL and extranasal angiocentric lymphomas despite the higher incidence of EBV association and the tendency for that peculiar anatomical site to be restricted to the former group.

Clinicopathologic study of PRAD1/cyclin D1 overexpressing lymphoma with special reference to mantle cell lymphoma. A distinct molecular pathologic entity

Mantle cell lymphomas (MCLs) are frequently associated with the overexpression of PRAD1/cyclin D1, activated by 11q13 translocation and its molecular counterpart BCL-1 gene rearrangement. We recently described the correlation of positive nuclear staining using monoclonal antibody against a PRAD1/cyclin D1 product with mRNA overexpression in MCLs. In the present study, we immunohistochemically investigated the PRAD1/cyclin D1 protein in a large series of 334 lymphoproliferative disorders, including 39 cases of MCLs on paraffin sections. Based on the cyclin D1 positivity, CD5 expression, and the morphologic features of the tumor tissue, four groups of MCL-related lesions were identified among the B-cell lymphomas examined: 36 cases with cyclin D1 overexpression, 35 (95%) of which exhibited CD5-positivity and MCL-morphology (Group 1); four cases of lymphomas with MCL morphology and CD5 expression but lacking cyclin D1 overexpression (Group II); four cases of lymphomas without cyclin D1 overexpression and surface CD5 but that fall within the morphologic boundaries of MCLs (Group III); and 11 cases of CD5-positive diffuse large cell lymphomas without cyclin D1 overexpression (Group IV). The Group I cases demonstrated quite homogeneous clinicopathologic features identical to those of MCLs. This group showed a poor prognosis (11% had 5-year survival), which is highly contrasted with that of Group II (100%). Although the four groups of MCL-related lesions sometimes overlapped in their histologic or phenotypic spectrums, each appeared to show distinct clinicopathologic and prognostic profiles. Our study provides a basis for further clarification of the nature of the neoplasms of Groups II, III, and IV. Moreover, this comprehensive study may indicate that the overexpression of PRAD1/cyclin D1 is biologically essential to defining MCLs.

Centroblastic and centroblastic-centrocytic lymphomas associated with prominent epithelioid granulomatous response without plasma cell differentiation: a clinicopathologic study of 12 cases

To clarify the clinicopathologic features of B-cell lymphoma associated with prominent epithelioid granulomatous responses other than immunocytomas, 12 patients were studied. There were six men and six women. The lymphoma generally affected elderly patients (median age, 58.5 years) and was mostly nodal in origin. Seven of the 12 patients had a localized lesion (stage I or II), and five had an advanced lesion (stage III or IV). Histologically, four patients showed a follicular growth pattern and eight a diffuse growth pattern. Based on the updated Kiel classification, nine patients showed centroblastic lymphomas, and three showed centroblastic-centrocytic lymphomas. The epithelioid cells were accumulated in large, poorly demarcated masses. Trabecular fibrosis compartmentalized in the lymph nodes, producing a vague nodular pattern in low-power fields. Immunohistochemical studies of the tumor cells revealed positive membrane staining with L26 in all 12 patients and with LN-1 antibody in 9 of 10 patients. Expression of the bcl-2 protein was present in all seven patients tested. Genotypic investigation exhibited germline configuration of the immunoglobulin heavy chain gene, the T-cell receptor beta-chain gene and the bcl-2 gene in all three patients investigated. By in situ hybridization, Epstein-Barr virus genomes were detected in only a few tumor cells in three of the patients tested. This study indicated that most, if not all, of the B-cell lymphomas with prominent epithelioid granulomatous responses other than immunocytoma were of follicular center cell origin.

[Association of Epstein-Barr virus with primary malignant lymphomas of the digestive tract]

The association of Epstein-Barr virus (EBV) with 85 non-Hodgkin lymphomas of the digestive tract in nonimmunocompromised cases was investigated, using in situ hybridization technique to detect EBV encoded small RNAs in paraffin sections. 85 cases (83 B-cell type and 2 T-cell type) included 3 gingivas, 1 tongue, 3 palates, 10 tonsils, 43 stomachs, 2 jejunums, 12 ileums, 3 ileo-cecal regions, 5 colons and 3 rectums. Out of 85 cases, 4 (4.7%) were EBV-positive, comprising 1 B-cell lymphoma of the tonsil, 2 B-cell lymphomas of the stomach, and 1 T-cell lymphoma of the rectum. On the other hand, EBV-positive rate in nasal/nasopharyngeal lymphomas examined for comparison was very high, 81.8% (9 out of 11). These results show that EBV is associated with only a small proportion of lymphomas of the digestive tract in nonimmunocompromised case, suggesting the existence of the other oncogenetic factors in the pathogenesis of this group of lymphomas.

Imprint cytology of cat scratch disease. A report of eight cases

The cytologic features of cat scratch disease (CSD) from eight cases in imprint smears are presented. All patients were clinicopathologically diagnosed with CSD as follows: 1) a history of animal exposure was recorded 2 to 4 weeks before lymphadenopathy; 2) the disease occurred in the autumn and winter months; 3) a characteristic histopathology in the biopsied lymph node specimens was observed; and 4) Warthin-Starry silver stain-positive bacteria were detected in four of the seven cases examined. The characteristic cytologic finding was the presence of confluent epithelioid cells with nearby and central scattering of neutrophils against a background of polymorphic inflammatory cells. Furthermore, a varying number of medium-sized to large lymphoid cells with an appearance suggestive of monocytoid B lymphocytes (MBLs) were noted to be associated with the epithelioid cells. These cytologic findings closely paralleled the histologic patterns of epithelioid cell granulomas, with and without MBLs, which we have previously reported are probably associated with the disease.

Inconsistent association of Epstein-Barr virus with CD56 (NCAM)-positive angiocentric lymphoma occuring in sites other than the upper and lower respiratory tract

We previously described nine cases of angiocentric lymphoma of a possible natural killer (NK)-cell lineage with a surface CD3-CD56+ phenotype occurring in sites other than the upper and lower respiratory tract. This study was performed to investigate the association of Epstein-Barr virus (EBV) with these lymphomas, using the polymerase chain reaction (PCR) for the presence of EBV-DNA, in situ hybridization (ISH) for EBV-encoded small RNAs (EBERs) and immunohistology for EBV-determined nuclear antigen-2 (EBNA-2) and latent membrane protein-1 (LMP-1) in paraffin sections. PCR and ISH produced almost identical results, and EBERs were identified in the nuclei of the lymphoma cells of three cases, two of which exhibited LMP-1 in the cytoplasm of tumour cells without EBNA-2 expression. Molecular genetic analysis revealed EBV to be incorporated into these three EBER-positive cases either clonally or biclonally. It was revealed by re-evaluation of their morphology with the established EBV status on each case that, in contrast to the rather variable and irregular cellular composition of the EBV-positive tumours, the EBV-negative tumours stood out because of their remarkably uniform 'blastoid' appearance, and could be grouped as blastic NK-cell lymphoma. The relationship of the EBV-positive cases with nasal NK-cell tumours has yet to be clarified.

Angioimmunoblastic T-cell lymphoma (angioimmunoblastic lymphadenopathy with dysproteinemia [AILD]-type T-cell lymphoma) followed by Hodgkin's disease associated with Epstein-Barr virus

A patient is described with angioimmunoblastic T-cell lymphoma (AIL) (angioimmunoblastic lymphadenopathy with dysproteinemia [AILD]-type T-cell lymphoma), which was later followed by Hodgkin's disease. At the time of the initial diagnosis, histological examination of a cervical lymph node showed a typical picture of AIL with abundant clear cells which were CD45RO+, CD43+, and CD20-, and there was no evidence of a monoclonal B-cell proliferation by immunohistochemical analysis. In situ hybridization for Epstein-Barr virus (EBV) was negative. Interposed by a bout of recurrence, the patient developed, 16 years later, a left subparotid mass which showed histologic features of Hodgkin's disease, mixed cellularity type. Diagnostic Reed-Sternberg cells and their variants were CD30+, CD15- and CD20+. Neither rearrangement of TCR beta and gamma chain genes nor of immunoglobulin heavy chain and kappa light chain genes was detected in DNA extract from fresh material. In situ hybridization showed the presence of EBV within the Reed-Sternberg cells. The data show that EBV was not etiologically related to AIL in this case. Further, the deficit in cellular immunity that accompanied AIL conceivably permit primary EBV infection or reactivation of latent infection, which eventuated in development of Hodgkin's disease, but the exact pathogenesis remains uncertain.

Ki-1 (CD30) positive anaplastic large cell lymphoma of T-cell phenotype developing in association with long-standing tuberculous pyothorax: report of a case with detection of Epstein-Barr virus genome in the tumor cells

We report a case of CD30 positive anaplastic large cell lymphoma of T-cell phenotype developing in association with long-standing tuberculous pyothorax. Phenotypic analysis showed CD1a-, CD2+, CD3+, CD4+, CD5-, CD8-, CD10-, CD19-, CD20 +/-, CD21-, CD25-, CD56-, T-cell receptor (TCR) alpha/beta antigens-, and HLA-DR+ phenotype. Neither rearrangement of TCR beta and gamma chain genes or of immunoglobulin heavy chain gene was detected in DNA extract from fresh material. The lymphoma cells were also shown to express the latent membrane protein-1 and the Epstein-Barr virus (EBV)-encoded nuclear antigen-2 by immunohistochemistry and EBV-encoded small RNAs by in situ hybridization.

Suppurative lesions without prominent epithelioid cell response in abscess-forming granulomatous lymphadenitis

To clarify the clinicopathological significance of the suppurative lesions without an epithelioid granulomatous response (SLs without Ep) in lymph nodes and their relationship to abscess-forming granulomatous lymphadenitis (AGL) and cat scratch disease (CSD), 10 cases were assessed clinicopathologically and immunohistologically. SLs without Ep were located in the subcapsular sinus, paracortical area and medullary cords, but not in the germinal centers. The microabscesses were surrounded by collections of monocytoid B-lymphocytes (MBLs), histiocytes without epithelioid features, neutrophils, small lymphocytes and small numbers of plasma cells. The majority of the MBLs seen in the SLs without Ep were of the large cell type. The histological triad of toxoplasmic lymphadenitis, i.e., reactive follicular hyperplasia, small clusters of epithelioid cells and aggregates of MBLs, were also seen in all cases. Some of the clinical and pathological findings in our 10 cases were characteristic of CSD, i.e., (1) cat exposure before the lymphadenopathy was in four of the 10 cases, (2) occurrence in autumn and winter months in all cases, (3) typical suppurative granulomas surrounded by palisaded epithelioid cells were in four of the 10 cases, and (4) Warthin-Starry silver stain-positive bacteria were detected in seven of the 10 cases. The results of our study suggest that SLs without Ep are an early stage of CSD.

Clinicopathologic study of CD56 (NCAM)-positive angiocentric lymphoma occurring in sites other than the upper and lower respiratory tract

The expression of the neural cell adhesion molecule (NCAM) (CD56, NKH-1) is a rare phenomenon in malignant lymphoma. Recently, several authors, including our group, described the clinicopathologic, phenotypic, and genotypic features of NCAM-positive tumors as a unique subgroup within a larger category of hematolymphoid malignancies. Ten cases of CD56+ angiocentric lymphoma occurring in sites other than the upper aerodigestive tract were studied for evaluating their characteristics. The disease occurred in six men and four women varying from 24 to 85 years (mean age, 53 years) who often exhibited a striking predilection for extranodal sites of involvement, such as the skin, gastrointestinal tract, and muscle, usually in the absence of peripheral lymphadenopathy. Although the cytologic appearances and immunophenotypic profile varied from case to case, these tumors often exhibited azurophilic granules, an angiocentric growth pattern, and surface CD3-, T-cell receptor (TCR) antigens-, and CD56+ phenotype without B-cell phenotype, except for a single case of CD3+, TCR alpha/beta+, and CD56+ phenotype. Genotype investigation exhibited germline configuration of the TCR beta and gamma chain genes and the immunoglobulin heavy chain gene in all five cases of surface CD3- phenotype examined, whereas the case of CD3+ phenotype showed rearrangement of TCR beta. They seem to constitute a distinct entity of the lineage spectrum spanning from natural killer (NK) cell to NK-like T cell.

A case of neural cell adhesion molecule-positive peripheral T-cell lymphoma associated with human T-cell lymphotrophic virus type 1 showing an unusual involvement of the gastrointestinal tract during the course of the disease

We report a case of neural cell adhesion molecule (NCAM)-positive peripheral T-cell lymphoma (PTCL), pleomorphic, medium and large cell type according to the updated Kiel classification, which was associated with human T-cell lymphotrophic virus type 1 (HTLV-1). The patient showed an unusual involvement of the gastrointestinal tract forming a bulky mass during the course of his disease, and a relatively indolent clinical course for 53 months until death. Phenotypic analysis showed CD2+, CD3-, CD4+, CD5+, CD7+, CD8-, CD16-, CD56+, and CD57- phenotype. Human T-cell lymphotrophic virus type 1 antibody was detected by the enzyme-linked immunosorbent assay. The proviral integration of HTLV-1 and the monoclonal rearrangements of T-cell receptor beta and gamma genes also were confirmed in DNA extract from fresh material. This fact calls attention to NCAM as one of the potential factors playing a role in the localization and behavior of lymphomas even within the category of PTCL associated with HTLV-1, ie, adult T-cell leukemia/lymphoma (ATLL).

Interdigitating cell sarcoma: a morphologic and immunologic study of lymph node lesions in four cases

Interdigitating cell sarcoma is an extremely rare tumor. Its presentation and histologic appearance has varied among the reported cases. In this study, the authors investigated four cases of the hematolymphoid malignancy arising within lymph nodes, which were considered to be of interdigitating cell origin. All patients presented in the 6th to 8th decade of life with peripheral lymphadenopathy, and had a relatively indolent clinical course, without bone marrow or skin involvement. Carcinomas were observed as a second neoplasm in two of four patients. Distinctive morphologic features are proliferation of histiocyte-like cells with nuclear pleomorphism and occasionally multinucleated, paracortical distribution sparing of B-cell regions, fibrosis, sinus infiltration, and a prominent eosinophil/plasma cell infiltrates. The combination of light microscopic, fine structural, and immunohistochemical features suggested that these tumors derive from interdigitating cells; these tumor cells expressed CD68 (KP1), S-100 protein and HLA-DR, but lack CD21 (1F8), desmosomes and Birbeck granules. The diagnosis of interdigitating cell sarcoma should be considered on any pleomorphic tumor with the features described in this report.

Imprint cytology of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue arising in the thymus: a case report

Low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) arising in the thymus is a very rare tumor with characteristic morphologic features. We describe a case of thymic low-grade B-cell MALT lymphoma occurring in a 59-yr-old woman with Sjögren's syndrome, in whom the definite diagnosis was difficult at the time of surgery. An immunohistologic and genotypic study, however, was diagnostic of lymphoma. A review of cytologic material was undertaken, and it was felt that the cytologic features in Giemsa-stained preparations in imprint smears were present that initially should have enabled the correct cytodiagnosis and distinction from the other thymic lesions. The findings presented in this study were considered to contribute to the cytodiagnosis of a thymic lesion, which might, in the past, have been erroneously interpreted as another lymphoproliferative disorder.

[A clinicopathologic study of primary gastric lymphoma of B-cell type among the Japanese with special reference to low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT)]

The most common primary site of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is the gastrointestinal tract, particularly the stomach. The relationship of MALT lymphomas, however, with the more commonly occurring large B-cell gastric lymphoma has not been directly discussed except in the report of Chan et al. (1990), which lacked clinical information regarding the behavior of these tumors. To elucidate the relationship between high-grade large-cell lymphoma and MALT lymphoma, we studied in detail the histopathological and clinicopathologic features with the survival date of 77 Japanese cases of primary gastric lymphoma (PGL) of B-cell type. Based on degree of morphologically recognizable low- or high-grade components of the tumor, PGL was divided into four types: 18 cases of pure MALT lymphoma (type I); 13 cases of MALT lymphoma with small area of high-grade lymphoma (type II); 22 cases of high-grade lymphoma with small areas of MALT lymphoma (type III); and 24 cases pure high-grade lymphoma (type IV). Corresponding to the differences in the histologic pictures of each type, there were differences in the gross appearance, pathologic stage (including depth of invasion) and prognosis. These data suggests that both MALT and high-grade lymphomas of the stomach belong to the same cell lineage and constitute a pathological spectrum and that the histological grouping of PGL is clinico-pathologically useful.

Clinicopathologic study of 212 cases of peripheral T-cell lymphoma among the Japanese

BACKGROUND

Postthymic/peripheral T-cell malignancy shows significant histopathologic and clinical diversity, even in its prognosis, and the correlations remain to be debated.

METHODS

The clinicopathologic features of 212 Japanese patients with these neoplasms were investigated.

RESULTS

There were 131 male and 81 female patients, whose ages ranged from 2 to 90 years (mean, 51.7 years). Lymphadenopathy was the most frequent clinical presentation, and the patients also had frequent skin lesions, hyperimmunoglobulinemia, hypercalcemia, and a rapid clinical course. Furthermore, the differences in the histologic features of each subcategory reflected the clinical pictures. The immunophenotypic analysis was indispensable in establishing a correct diagnosis, and the high-grade tumors often showed loss of pan-T antigens.

CONCLUSIONS

The histopathologic classification proposed by Suchi et al., which has been incorporated into the updated Kiel classification, showed a good prognostic correlation.

Changes in histopathological features of gastric carcinoma over a 26-year period (1965-1990)

Epidemiological study has shown that the incidence rate of gastric carcinoma in Japan has declined recently. To explore the factors that have influenced this decrease, the changing pattern in clinico-pathological features of gastric carcinoma was studied from the epidemiological point of view. The 5,015 cases of gastric carcinoma treated with gastrectomy at Aichi Cancer Center Hospital from 1965-1990 were divided into two histopathological types: the well-differentiated and other types. Proportional distribution was compared over the three different periods (1965-1973, 1974-1982, 1983-1990) according to the clinico-pathological features of the gastric carcinoma, i.e., sex, age, lesional location, etc. The recent relative decline of gastric carcinoma is due mainly to the decline of carcinoma of the well-differentiated type. This decline has been highly correlated to the decline in carcinoma of the antrum, which has been the most common in Japan. This changing pattern of clinicopathological features of Japanese gastric carcinoma might be affected by the change of exposure patterns to epidemiological factors, i.e., a Westernizing diet.

Malignant lymphoma of Waldeyer's ring. A histological and immunohistochemical study

The histopathological and immunohistological features of non-Hodgkin's lymphoma limited to the Waldeyer's ring were studied in 22 Japanese patients using a panel of T- and B-cell markers on paraffin-embedded sections. All cases showed a diffuse growth pattern. Twenty cases were B-cell lymphomas and two were T-cell lymphomas. In contrast to the primary malignant lymphomas of the nasal cavity and paranasal sinuses, in which T-cell neoplasms are more frequently seen, the majority of the primary Waldeyer's ring lymphomas were B-cell neoplasms. Sixteen of the 20 cases of B-cell lymphoma were centroblastic lymphomas, and the monomorphic variant comprised the majority of these; the other three B-cell lymphomas were immunocytomas. Two of the T-cell lymphomas showed morphological features of angiocentric lymphomas.