Abstract
A liver tumor was detected via abdominal ultrasound in a 40-year-old man undergoing a medical check-up. Blood chemistry indicated unimpaired liver function, virus marker tests were negative, and tumor marker levels were within the normal range. A 36-mm tumor mass projecting from liver S6 was slightly enhanced from the arterial to the portal vein phase on contrast-enhanced computed tomography, with washout during the delayed phase. The differential diagnosis included hepatocellular carcinoma and sereral other benign liver tumors ; As a percutaneous transhepatic biopsy could potentially induce tumor dissemination, a partial hepatectomy was conducted. The surface of the resected specimen indicated a single, solid tumor nodule with somewhat unclear boundaries and a yellowish-white color. Histopathologically, prominent infiltration of small-to-medium-sized lymphocytes was accompanied by lymphoid follicles in the portal vein area. Immunostaining detected CD3 and bcl-2 positivity, strong CD20 positivity, and CD10 negativity, leading to a diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma. Although primary hepatic MALT lymphoma is relatively rare disease, it should be included in the differential diagnosis of a liver tumor with non-specific imaging findings.
