Primary liver carcinoma arising in people younger than 30 years.

Primary liver carcinomas in children and young adults are uncommon and poorly described. We examined primary liver carcinomas in people younger than 30 years and performed immunostains for markers of biliary (cytokeratin [CK] 7, CK19, CD56) and hepatocellular (HepPar) differentiation. We found 23 primary liver carcinomas were found: 13 hepatocellular carcinomas (HCCs), 9 fibrolamellar carcinomas (FLCs), and 1 cholangiocarcinoma. Most HCCs showed compact (n = 7) or trabecular (n = 4) growth patterns. The Edmondson grades were as follows: 1, 3 tumors; 2, 8 tumors; and 3, 2 tumors). All HCCs and FLCs were HepPar(+). All FLCs and 7 of 9 HCCs were CK7(+). In contrast, a control group of 65 adult HCCs showed less CK7 positivity (24 [37%]; P = .03). CK19 was positive in 2 HCCs and CD56 in 1 HCC. No chronic background liver disease was seen, although 3 cases showed foci of altered hepatocytes. HCCs are the most common primary liver carcinoma in children and young adults followed by FLCs. They are morphologically similar to adult HCC, but more likely to be CK7(+).