Pathology of combined hepatocellular-cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma is a rare primary neoplasm in the liver. It has gained increasing recognition recently, which in part may be due to more extensive sampling of the explants and surgical resection specimens, the diagnostic challenges encountered in the clinical practice, and the yet to be determined clinical outcome, but partly may be attributed to its intriguing histogenesis/cells of origin. This review aims to update combined hepatocellular-cholangiocarcinoma with an emphasis on the pathological diagnosis, including the differential diagnosis and its diagnostic pitfalls, the possible cell of origin of this neoplasm, and its clinical outcome.