4. Paroxysmal Nocturnal Hemoglobinuria

Mucoepidermoid carcinoma of the intrahepatic bile duct is a rare variant of cholangiocarcinoma: it is composed of mucus-secreting squamous cells and glandular cells within the same nests. This tumor is very aggressive, with high-grade malignancy, and has a poor prognosis. In the international literature, only 17 cases of mucoepidermoid carcinoma originating in the hepatic bile duct system have been reported until now. We report an autopsy case of mucoepidermoid carcinoma of the intrahepatic bile duct with metastasis to the cranial skin in a Japanese man who was more than 70 years old. This cancer metastasizes to many organs, but skin metastasis is extremely rare.