Extrahepatically growing hepatocellular carcinoma diagnosed after presentation with peritoneal dissemination: a case report.

A man in his 40s presented with mildly elevated alpha-fetoprotein (AFP) levels during routine screening. Initial evaluation, including abdominal ultrasonography, revealed no intrahepatic mass, and the patient was placed under surveillance. Approximately 20 months later, AFP and PIVKA-II levels increased to > 200 000 ng/mL and 1524 mAU/mL, respectively. Contrast-enhanced computed tomography (CT) demonstrated diffusely enhancing peritoneal nodules with ascites; however, no definite intrahepatic tumor was detected. Diagnostic laparoscopy revealed multiple soft, reddish-brown nodules involving the peritoneum, omentum, and mesentery. Histopathological examination with immunohistochemistry confirmed disseminated hepatocellular carcinoma (HCC). Retrospective image review identified a small hypervascular nodule with washout extending from the left lateral liver segment toward the left triangular ligament, consistent with a pedunculated extrahepatic HCC. Despite treatment, the patient died 14 months after diagnostic laparoscopy. This case demonstrates that extrahepatically growing HCC may initially present with peritoneal dissemination, even in the absence of an apparent intrahepatic mass.