Fibrin-associated large B-cell lymphoma (FA-LBCL) is a rare type of lymphoma usually associated with Epstein-Barr virus (EBV) infection. We report a case incidentally detected in a right ovarian mass of a 53-year-old woman. The patient presented with bloating and weight gain over 8 months. Imaging studies showed a 20.7 cm, complex right adnexal mass. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Macroscopic examination revealed a 25 x 18.5 x 9.5 cm predominantly cystic right ovarian mass with focal solid areas. Microscopically, most of the mass was a leiomyoma with hyaline necrosis and extensive cystic degeneration. In areas, the cyst showed focally necrotic, fibrinous material associated with small aggregates of round and atypical lymphoid cells with prominent karyorrhexis and mitotic activity These large cells were confined within the cystic spaces. Immunohistochemical analysis showed that the atypical cells were positive for CD20, CD30, CD79a and MUM1/IRF4, and were negative for CD3, CD10 and BCL6, supporting B-cell lineage. In situ hybridization for Epstein-Barr virus-encoded RNA (EBER ISH) was also positive in the atypical cells supporting the diagnosis of EBV-positive fibrin-associated large B-cell lymphoma. The patient subsequently received four cycles of chemotherapy using rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP). Computed tomography (CT) scan of the neck, chest, abdomen and pelvis 5 months after the last chemotherapy cycle showed no evidence of disease. After a follow-up of 17 months, the patient is alive with no evidence of disease. This report is being used to discuss the salient features of this rare entity and its differential diagnosis.
Keywords: B-cell; EBV; Fibrin-associated; Lymphoma.
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