Simultaneous occurrence of primary diffuse large B-cell lymphoma and extranodal marginal zone (MALT) B-cell lymphoma in the gallbladder: a case report.

Primary lymphoma of the gallbladder is extremely rare. We present an asymptomatic case of primary combined DLBCL--MALT lymphoma of the gallbladder in a 78-year-old man in whom definitive diagnosis was made with laparotomic cholecystectomy. Preoperative diagnosis was supported by NMR, CT and PET scans. The pathological report identified a polypoid lesion measuring 3.5 cm in diameter. A non-Hodgkin lymphoma with two different coexisting patterns was identified histologically: large diffuse B-cell lymphoma (DLBCL) associated with focal areas of extranodal marginal zone B-cell lymphoma (MALT-type) of the gallbladder. The postoperative course was uneventful and the patient is currently without clinical or radiological signs of disease. Chemotherapy was not indicated due to cardiopathy. In conclusion, a primary gallbladder lymphoma is a rare entity. Radiological findings may be helpful, but cholecistectomy may be necessary for definitive diagnosis. In this report, we describe the possible association between MALT and DLBCL of the gallbladder.