Case Report: Primary hepatic carcinosarcoma with ectopic β-hCG secretion and a paraneoplastic leukemoid reaction mimicking gynecologic and hematologic disease.

Primary hepatic carcinosarcoma is an exceptionally rare and highly aggressive malignancy, and ectopic β-hCG production and paraneoplastic leukemoid reaction are both uncommon findings in solid tumors. We report the case of a 47-year-old woman who initially presented with abnormal vaginal bleeding and elevated serum β-hCG, raising concern for a pregnancy-related disorder. Diagnostic curettage showed no evidence of pregnancy or trophoblastic disease, yet the β-hCG level continued to rise. At the same time, she developed extreme leukocytosis, and bone marrow examination favored a leukemoid reaction rather than hematologic malignancy. Imaging subsequently revealed a rapidly enlarging mass in the right hepatic lobe with necrosis, satellite lesions, vascular involvement, and hilar nodal disease. Surgical resection was performed because the lesion was considered resectable and tissue diagnosis was required. Histopathology demonstrated a poorly differentiated primary hepatic carcinosarcoma with β-hCG expression in a subset of tumor cells. After surgery, the white blood cell count, serum β-hCG, and PIVKA-II levels all fell markedly, supporting their paraneoplastic origin. However, the tumor recurred rapidly, and the patient died approximately 1 month after surgery. This case shows that persistent β-hCG elevation and marked leukocytosis, when unexplained by gynecologic or hematologic disease, may rarely be the presenting clues to an aggressive primary hepatic malignancy. Importantly, persistent β-hCG elevation and marked leukocytosis should not be interpreted in isolation as gynecologic or hematologic disease when imaging reveals a rapidly enlarging liver mass.