Unusual Initial Presentation of Herpes Simplex Virus as Inguinal Lymphadenopathy

Genital herpes simplex virus (HSV) infections are a common cause of inguinal lymphadenopathy. However, surgical excision of enlarged inguinal nodes is almost never performed to initially diagnose genital herpes simplex virus, due to the distinct external presentation of genital herpetic vesicles that usually occur with the first symptoms of infection. Therefore, the histologic and immunophenotypic features of HSV-associated inguinal lymphadenopathy are unfamiliar to most pathologists. The current report describes the lymph node pathology of two immunocompetent patients, whose initial HSV diagnosis was established through surgical excision of enlarged inguinal lymph nodes. Histologic examination showed features consistent with viral lymphadenopathy, including florid follicular hyperplasia, monocytoid B-cell hyperplasia, and paracortical hyperplasia without extensive necrosis. Immunohistochemical stains for HSV antigens, using polyclonal anti-HSV I and II antibodies, demonstrate strong immunoreactivity for HSV in a small number of cells in the subcapsular sinuses, especially in areas with monocytoid B-cell hyperplasia. Rare scattered HSV-positive cells also are identified in paracortical areas and germinal centers. We conclude that an initial diagnosis of genital HSV infection may be established by inguinal lymph node biopsy.

A Distinct Entity of Ocular Adnexal MALT Lymphoma with Trisomy 18.

Background: It remains unknown whether primary ocular adnexal MALT lymphoma is a homogenous disease, because there have been few reports on cytogenetic or molecular analysis of this disease. Patients and Methods: In 34 cases of ocular adnexal MALT lymphoma, we performed interphase fluorescence in situ hybridization (FISH) analysis to detect IgH/MALT1 and API2/MALT1 fusion genes. Aneuploidy of chromosome 3, 7, 12 and 18 was also identified using corresponding centromere probes. We defined trisomy when three centromeres were recognized in FISH analysis. Histopathologic features were reviewed and categorized according to the degree of plasma cell differentiation, monocytoid B cell feature, nodularity, abundance of reactive germinal centers, multikaryocytic cells, contaminated T cells, Duthcer bodies, and lymphoepithelial lesions (LELs). Correlations among FISH analysis, histopathologic features, and clinical data were analyzed. Results: FISH analysis showed 1 (3%) IgH/MALT1 fusion, 21 (62%) trisomy 3, 16 (47%) trisomy 18, and 3(9%) trisomy 7 cases. No cases showed API2/MALT1 fusion or trisomy 12. Existence of these cytogenetic change did not influence the degree of morphological features significantly, except for trisomy 18; Cases with trisomy 18 had significantly more abundant LEL cells, monocytoid B cells and residual reactive germinal centers, but less nodules, contaminated plasma cells and large cells. Cases with trisomy 18 showed distinct features of female dominance, younger age, and included more cases originated from conjunctiva. In total, five (15%) of 34 patients relapsed between 21 and 103 months, and all of them were found to have trisomy 18. Conclusions: Aneuploidy is found in a ceratin subset of ocular adnexal MALT lymphoma by FISH analysis. Cases with trisomy18 may make a distinct clinicopathlogic entity.

Transformation of Monocytoid B-Cell Lymphoma to Large Cell Lymphoma Associated With Crystal-Storing Histiocytes

We report a case of crystal-storing histiocytosis associated with large cell lymphoma in a patient with a history of monocytoid B-cell lymphoma 10 years previously. The cervical lymph node biopsy showed a diffuse proliferation of large lymphocytes with vesicular nuclear chromatin and distinct nucleoli. These lymphocytes were associated with numerous immunoglobulin λ light-chain crystal-storing histiocytes, which morphologically resembled rhabdomyoblasts. Occasional lymphoid cells also showed large immunoglobulin crystals. This case establishes the association of crystal-storing histiocytes with lymphomas of mucosa-associated lymphoid tissue and emphasizes the need for immunophenotyping to distinguish these unusual cases from other tumors, particularly adult rhabdomyomas.