[Diffuse large B-cell lymphoma initially manifested by massive ascites and a small gastric lesion, clinically mimicking primary effusion lymphoma (PEL) in the abdominal cavity: a case report and review of the literature on Japanese PEL patients].

A 50-year-old man was admitted because of increasing massive ascites. While lymphoma cells (diffuse large B-cell lymphoma: DLBCL) were detected in the ascites, pleural effusion, cerebrospinal fluid and bone marrow, no tumor masses other than a submucosal lymphoma lesion in the stomach only 1 cm in diameter were identified. The patient was treated with chemotherapy including rituximab (R-CHOP-ESHAP) and injection of methotrexate and dexamethasone into the medullary cavity as well as radiation to the whole brain, and achieved complete remission 4 months later. The present case suggests that DLBCL can initially manifest as a form of effusion lymphoma with minimum solid tumor component. The distinctive clinical features of Japanese patients with primary effusion lymphoma are also reviewed.