Primary adenosquamous carcinoma of the liver detected during cancer surveillance in a patient with primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is associated with significant risk for hepatobiliary cancers. Primary hepatic adenosquamous carcinoma (ASC), a rare subtype of cholangiocarcinoma, is composed of both adenocarcinoma and squamous cell carcinoma components. We herein report the case of a patient with PSC who was diagnosed with ASC of the liver during cancer surveillance. A 74-year-old male patient was diagnosed with PSC based on blood chemistry and magnetic resonance cholangiopancreatography findings, and regular surveillance for hepatobiliary cancers was initiated. Four years later, the level of carbohydrate antigen 19–9 rapidly increased, and abdominal imaging studies revealed a cystic mass, 40 mm in diameter, containing a solid component in the right liver lobe. Right lobectomy was performed with a pre-operative diagnosis of cholangiocarcinoma; however, the definitive diagnosis was ASC based on the presence of adenocarcinoma and squamous cell carcinoma components in the resected tumor. The patient did not receive post-operative chemotherapy, but was alive for more than 4 years without recurrence at last follow-up. The present case illustrates that regular surveillance and curative resection might achieve long-term survival in hepatic ASC, which has a poor prognosis.