A clinicopathologic study of intrahepatic cholangiocarcinoma containing a component of squamous cell carcinoma.

Eleven cases of cholangiocarcinoma containing a component of squamous cell carcinoma (CC-SCC) were reviewed clinicopathologically in comparison with 82 cases of common cholangiocarcinoma presenting as a pure form of adenocarcinoma (CC-AC). The former type was prone to develop in a rather advanced stage of the disease, as indicated by short survival time, large tumor size, aggressive modes of intrahepatic spreading, and frequent metastasis. Histologically, the area of squamous cell carcinoma ranged from focal to overwhelming. The occurrence of the squamous element could be interpreted as the result of the metaplastic transformation of adenocarcinoma cells because of the intimate coexistence of the two types in the primary and metastatic lesions. It also was suggested that anaplastic carcinoma cells could sometimes differentiate into squamous cell carcinoma. In no instances was there any squamous metaplasia of the bile ducts demonstrated; therefore, there was no supporting evidence for the possibility of squamous metaplasia of the bile duct epithelium and subsequent malignant transformation.