Ectopic β-hCG-Expressing Hepatic Neoplasm with Cutaneous Metastasis in a Young Postpartum Woman: A Case Report and Literature Review

This case report describes a rare presentation of intrahepatic cholangiocarcinoma (ICC) in a 33-year-old postpartum woman, with extensive systemic and cutaneous metastases as the initial clinical manifestations. She presented with a palpable mass on her back and was subsequently found to have hepatic masses accompanied by elevated serum carbohydrate antigen (CA) 19-9 and β-human chorionic gonadotropin (β-hCG). Subsequent imaging and histopathological evaluation confirmed a poorly differentiated ICC with atypical trabecular, nested, and sheet-like growth patterns, without evidence of trophoblastic differentiation. Immunohistochemical analysis revealed a Cytokeratin (CK) 7-negative/CK19-positive immunophenotype and moderate hCG expression (++). In postpartum patients with unexplained β-hCG elevation unrelated to pregnancy, ectopic β-hCG-secreting tumors, such as ICC, should be considered in the differential diagnosis after exclusion of trophoblastic and germ cell neoplasms, particularly when accompanied by elevated carbohydrate antigen 19-9 levels.