Primary hepatic marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type: case report and review of the literature.

A primary hepatic marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT) is very rare. We found a solitary mass 27 mm in size in the left lobe of the liver of a 58-year-old Japanese man with a history of hepatitis-C infection. Based on the results of imaging studies, the tumor was diagnosed as a hepatocellular carcinoma (HCC). The left lobe of the liver was lobectomized and microscopic findings showed that the tumor was a hepatic MALT lymphoma, while immunohistochemistry showed it to be positive for CD20 and CD79a. In a fluorodeoxyglucose-positron emission tomography examination integrated with computed tomography scanning (FDG-PET CT) before surgery, the tumor was revealed to have a high standardized uptake value (SUV) for FDG. The patient received chemotherapy after surgery. To the best of our knowledge, 45 cases had been reported with a mean age for all patients of 61.4 years. The pathogenesis remains unclear, although half of the patients had a past history of chronic inflammatory liver disease. Surgical resection was performed in most cases and some patients received postoperative chemotherapy or radiotherapy. The clinicopathologic characteristics and management of this extremely rare disease are also discussed.