Discordant lymphoma: Report a case of possible transformation from initial large cell B lymphoma to histiocytic sarcoma.

An autopsy case of discordant lymphoma comprising large cell B lymphoma and histiocytic sarcoma (true histiocytic lymphoma) was reported. A 70-year-old woman with large cell B lymphoma of 14 months duration developed fever, anemia, and jaundice. She died of gastric bleeding shortly after the initiation of chemotherapy. Autopsy findings revealed multiple nodular masses throughout the liver, lungs, bone marrow and paraaortic lymph nodes. These masses consisted of containing atypical histiocytes associating with common phagocytic figures, with immunohistochemical features of histiocytic sarcoma. The original large cell B lymphoma was still present in the right adrenal gland. Discordant lymphomas are those in which two distinct histological patterns occur in separate anatomic disease sites. This is the first reported case of histiocytic sarcoma arising in association with large B cell lymphoma. Sequential presence of histiocytic sarcoma seemed to be different mutation stages of the neoplastic B lymphocyte in the cell cycle of a single cell type.