[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.

Metastatic colon cancer mimicking Crohn's disease.

A 66-year-old Japanese woman presented with intestinal obstruction and right-sided hydronephrosis. Although upper gastrointestinal endoscopy demonstrated signet-ring cell gastric carcinoma, colonoscopy and barium enema study yielded findings mimicking Crohn's disease in the colon, that is, skipping longitudinal ulcer scarlike strictures, cobblestone appearance, segmental stricture, and pseudosacculations. After total gastrectomy and right-sided hemicolectomy, the final diagnosis of gastric cancer extensively involving the colon, and not of Crohn's disease complicating gastric cancer, was established.