A rare hepatic and biliary tract tumor, arising either in the gallbladder itself or in the epithelium lining the extrahepatic biliary tree, the cystic duct and peribiliary glands. It is characterized by a substantial keratinization with abundant keratohyalin pearls and central deposition of dense keratin material within infiltrative nests and locally aggressive nature. In the early stages of the disease symptoms are vague and nonspecific (abdominal pain, jaundice and vomiting). In the advanced stages it may present with a bulky tumor and symptoms of adjacent organ involvement. [from
ORDO]