Evaluating breast lymphoplasmacytic infiltrates: a multiparameter immunohistochemical study, including assessment of IgG4.

Lymphoplasmacytic infiltrates in the breast, a modified skin appendage, include lymphocytic lobulitis, other nonspecific benign proliferations, and mucosa-associated lymphoid tissue (MALT)-type lymphoma. Distinguishing these entities, all of which may be B-cell rich and may have associated sclerosis, can be difficult. In addition, the proportion that represents IgG4-related disease is unknown, and the similarity of MALT lymphomas to primary cutaneous marginal zone lymphoma is uncertain. To address these questions, the clinical, histologic, and immunohistochemical features of 50 benign and malignant breast lymphoplasmacytic infiltrates (10 lymphocytic lobulitis, 1 granulomatous, 19 not otherwise specified, 20 MALT lymphomas) were evaluated. Compared with the MALT lymphomas, benign cases had a less dense infiltrate (P < .001), fewer but more histologically apparent germinal centers (P < .001), and more marked fibrosis (P < .0001). Greater than 60% B cells were present in 23% (7/30) benign cases versus 75% (15/20) MALT lymphomas (P = .0003). Plasma cells were predominantly IgG+ in 83% (24/29) benign cases and predominantly IgM+ in 73% (14/19) MALT lymphomas (P < .0001). None of the benign cases had greater than 50 IgG4+ plasma cells/high-power field, and only 1 lymphocytic lobulitis case had an IgG4/IgG ratio exceeding 40% and no clinical evidence for extramammary IgG4-related disease. Although there may be some overlapping features, routine histopathology together with limited immunohistochemical stains can distinguish benign from neoplastic lymphoplasmacytic infiltrates in the breast. Despite frequent sclerosis, the breast is not a common site of unrecognized IgG4-related sclerosing disease. Although there are similarities, breast MALT lymphomas can be separated from cutaneous marginal zone lymphoma.

CD200 flow cytometric assessment and semiquantitative immunohistochemical staining distinguishes hairy cell leukemia from hairy cell leukemia-variant and other B-cell lymphoproliferative disorders.

OBJECTIVES: To evaluate CD200 expression in B-cell proliferative disorders. METHODS: We analyzed 180 recent specimens of B-cell neoplasms for CD200 expression by flow cytometric immunophenotypic analysis, which is better able to assess relative intensity of staining than immunohistochemical staining. RESULTS: We found that hairy cell leukemia exhibits a high level of staining for CD200 in comparison to other B-cell lymphoproliferative disorders, including hairy cell leukemia-variant (HCL-V), marginal zone lymphoma, and lymphoplasmacytic lymphoma. We confirmed this observation by semiquantitative immunohistochemical staining. CONCLUSIONS: Assessment of the CD200 expression level is helpful to distinguish HCL from HCL-V and other B-cell lymphoproliferative disorders and in the differential diagnosis of B-cell neoplasms in general.

[Assessment of BIOMED-2 assays for detection of clonal Ig gene rearrangements in mature B-cell lymphomas].

OBJECTIVE: To evaluate the efficiency of the BIOMED-2 PCR assay and its implication in the diagnosis of mature B-cell non-Hodgkin's lymphomas. METHODS: Clinical, morphological and immunohistochemical features of 72 cases of non-Hodgkin's lymphomas were studied, including 25 reactive lymphoid hyperplasia, 37 diffuse large B cell lymphomas (DLBCL) and 35 extranodal marginal zone lymphomas of mucosa associated lymphoid tissues (MALT lymphoma and in addition, 25 cases of reactive lymphoid hyperplasia were used as the controls). DNA was exacted from the paraffin embedded formalin fixed tissue blocks and the quality of DNA was assessed using the BIOMED-2 specimen control reaction. Adequate samples were then analyzed by BIOMED-2 for immunoglobulin heavy and kappa light chain rearrangements. RESULTS: Adequate DNA was obtained in 83 of 97 samples, including 60 mature B cell lymphomas and 23 reactive lymphoid hyperplasia. Clonal B-cell gene rearrangements were detected in 57 of 60 (95%) lymphomas. In contrast, clonal Ig gene rearrangements were not detected in any of the 23 cases of reactive lymphoid hyperplasia. CONCLUSION: BIOMED-2 assay is highly sensitive and specific for the detection of clonal B cell gene rearrangement using routine paraffin embedded formalin fixed specimens.

Assessment of the role of hepatitis C, Helicobacter pylori and autoimmunity in MALT lymphoma of the ocular adnexa in 45 Austrian patients.

INTRODUCTION: A recent series from Italy has suggested a pathogenic link between hepatitis C virus and MALT lymphoma of the ocular adnexa. The hypothesis of our study was to prove this concept in Austrian patients with MALT lymphoma of the ocular adnexa. MATERIALS AND METHODS: A total of 45 patients presenting with MALT lymphoma of the ocular adnexa were assessed for the presence of infection with hepatitis A, B and C. Furthermore, extensive staging to evaluate the extent of disease along with analysis of Helicobacter pylori-infection, the presence or absence of autoimmune diseases (AD) and assessment of MALT-lymphoma specific genetic changes was performed. RESULTS: Only 2/45 (4%) patients were tested positive for hepatitis C, while 10/45 (22%) had an underlying AD and 15/39 (38%) had HP infection. Chromosomal aberrations were detected in 19 (54%) of 35 patients analyzed. Disseminated disease was a significant risk factor for relapse (p=0.014). DISCUSSION: Our series suggests that infection with hepatitis C is not a significant contributor to the pathogenesis of ocular adnexal MALT lymphoma in the Austrian population, while a substantial proportion of these patients suffer from autoimmune conditions.