Lymphoid hyperplasia detected as a single mass in the gallbladder: report of a case.

We herein report a case of lymphoid hyperplasia of the gallbladder that showed unique images on computed tomography and ultrasonography. A 42-year-old female was referred to our hospital for evaluation and treatment of a gallbladder tumor. Ultrasonography and computed tomography showed a mass in the wall of the gallbladder neck, without typical findings of benign or malignant tumors. The serum levels of tumor markers, such as carcinoembryonic antigen, carbohydrate antigen 19-9, alpha-fetoprotein, and cytokeratin 19 fragment, were all within normal limits. Laparoscopic cholecystectomy was therefore performed. There were no stones in the gallbladder. Macroscopically, the submural tumor had a clear border without a capsule and a cystic portion. Its cut surface was grayish white. Microscopically, many lymph follicles with germinal centers were recognized in the subserosal layer. The lymphocytes were morphologically normal. We diagnosed lymphoid hyperplasia with chronic cholecystitis. Lymphoid hyperplasia of the gallbladder is extremely rare.