Hyperplastic polyp of the gallbladder in a child.

We report a case of hyperplastic polyp of the gallbladder in a 6-year-old girl, successfully treated by laparoscopic cholecyctectomy after a 2-year follow-up from the original diagnosis. On her first admission, serum amylase level was very high, so that congenital pancreaticobiliary maljunction (PBM) was suspected. Although it became clear afterwards that the high serum amylase level was derived from a mumps infection, the diagnosis of PBM was not excluded until intraoperative cholangiography was conducted. The tumor in the gallbladder had doubled in size in 2 years. It was not possible to obtain biopsy specimens for histological diagnosis, so the risk of the tumor being malignant could not be completely excluded until surgical resection had been carried out. In spite of the rapid tumor growth, no neoplastic features were seen in the tumor by histopathological examination of the resected specimen; thus, a diagnosis of a hyperplastic polyp of the gallbladder was made.