Benign tumors and tumor-like lesions of the gallbladder and extrahepatic biliary tract

The gallbladder is one of the most common specimens encountered in surgical pathology laboratories worldwide. A vast majority of these show merely cholelithiasis and chronic cholecystitis, however, a wide variety of benign tumors and tumor-like lesions can occur in the gallbladder and are largely discovered incidentally. Benign tumors of the gallbladder and extrahepatic bile ducts are similar, however, the incidences vary by site. The epithelial tumors include adenomas that can be gastric, intestinal or biliary types, and cystadenomas. Mesenchymal tumors are even more rare and identical to their soft tissue counterparts. Of these as a group, the neurogenic lesions are most common. The tumor-like lesions include various types of metaplasia, hyperplasia, heterotopia and chronic cholecystitis-associated lesions. These various benign and tumor-like lesions can mimic malignancy clinically, radiologically and sometimes even microscopically. Awareness of these benign lesions is necessary to avoid a wrong diagnosis of malignancy.