Hepatic adenosquamous carcinoma with sarcomatous transformation: a case report and review of the literature.

Adenosquamous carcinoma (ASC) with the presence of a sarcomatous component is exceptionally uncommon in intrahepatic cholangiocarcinoma (iCCA). We report a case of hepatic ASC with rhabdoid transformation, one variation of sarcomatous change. A 72-year-old man was admitted to our hospital after being diagnosed with a 45 mm-diameter neoplastic lesion in the right hepatic duct on abdominal computed tomography. Laboratory findings showed increases in AST, ALT, ALP, gamma-GT, CA19-9 and DUPAN-II. The patient then underwent an extended right hepatectomy. Histopathologically, the tumor was composed of an ASC component within an abundant fibrous stroma and a sarcomatoid carcinoma component. By immunohistochemistry, keratin 7 and keratin 19 were expressed by all tumor cells. Expression of keratin 5/6, p40 and p63 was restricted to the squamous component. The sarcomatoid component was immunoreactive for vimentin with no loss of INI1 expression. This component also showed a loss of membranous E-cadherin expression and a reduction of membranous β-catenin expression. Staining for desmin, myoglobin and HepPar1 was negative in any tumor cells. The patient died of liver failure 3 months after surgery. This report aims to provide a better understanding of the clinicopathological characteristics and disease progression of the rare variants of iCCA to aid diagnosis and treatment.
(© 2024. The Author(s) under exclusive licence to The Japanese Society for Clinical Molecular Morphology.)