Synchronous primary gastric mantle cell lymphoma and early gastric carcinoma: a case report.

Mantle cell lymphoma (MCL) commonly invades the gastrointestinal (GI) tract. However, primary GI MCL is rare. We experienced a case of synchronous early gastric cancer (EGC) with primary gastric MCL found as a single early lesion rather than as multiple lymphomatous polyposis. An EGC was found in the cardia of a 64-year-old male on a routine GI endoscopic examination. A specimen obtained by total gastrectomy revealed another slightly elevated lesion in the pylorus. Microscopically, monotonous small- to medium-sized atypical lymphocytes with angulated nuclei formed a mass beneath the gastric mucosa. On immunohistochemical staining, the tumor cells revealed strong positivity for cyclin D1, positivity for both CD20 and bcl-2, and weak positivity for CD5, suggesting MCL. Clinically, there was no lymphoma in any other part of the body. This is the first case of an EGC accompanying a primary gastric MCL. Further investigation of a relationship between MCL and EGC and of factors that may affect GI involvement of MCL is necessary.