From the Archives of the AFIP

A diverse spectrum of benign tumors and tumorlike lesions arises from the gallbladder and bile ducts, and despite their diversity, these lesions share common embryologic origins and histologic characteristics. Although these lesions are relatively uncommon, their importance lies in their ability to mimic malignant lesions in these locations. Benign neoplasms are derived from the epithelial and nonepithelial structures that compose the normal gallbladder and bile ducts. The epithelium gives rise to adenomas, cystadenomas, and the unusual condition of biliary papillomatosis. Granular cell tumors, neurofibromas, ganglioneuromas, paragangliomas, and leiomyomas are examples of benign tumors that may originate from…