Intrahepatic cholangiocarcinoma
(ICC), a tumor with biliary tract differentiation pathologic features, is the
second most common primary liver cancer worldwide after HCC, accounting for
15-20% of all primary liver cancers; the incidence of ICC is on the rise, especially
in Western Countries.
The morphologic classification system for primary liver
cancer proposed by the Liver Cancer Study Group of Japan divides ICC into three
types based on macroscopic appearance: the mass-forming type, the periductal in filtrative type, and the intraductal growing type. Mass-forming ICC (IMCC) is
the most common type and shows a radial growth pattern, invading into the
adjacent hepatic parenchyma.
Combined
hepatocellular-cholangiocarcinoma (cHCC-CC), is a rare (incidence among primary
liver cancer ranges from 0.4% to 14%) but an increasingly recognized primary
malignant neoplasm in the liver. It is “a tumor containing unequivocal elements of both hepato cellular and cholangiocarcinoma that are intimately admixed” as defined by the World Health Organization (WHO) classification. In 1949 Allen
and Lisa classified cHCC-CC into three subtypes: type A, ‘double cancer’ (HCC
and CC are present at different sites within the same liver); type B, ‘combined
type’ (HCC and CC are present at adjacent sites and mingle with continued
growth); type C, ‘mixed type’ (HCC and CC components are combined within the
same mass).