Primary Hepatic Osteosarcoma: A Rare Cause of Primary Liver Tumor

INTRODUCTION: Extraosseous osteosarcomas are rare, accounting for approximately 4% of all osteosarcomas. A literature review yields very few cases of osteosarcoma primarily arising from the hepatic parenchyma. CASE REPORT: This report describes a case of a man in his 50s with a history of hepatitis C and cirrhosis who presented with 5 days of progressive right upper quadrant pain. Magnetic resonance imaging of the abdomen and pelvis demonstrated a 4.4 cm × 4.8 cm × 4.8 cm right hepatic lobe mass with a large area of necrosis and peripheral enhancement. The subsequent liver biopsy showed few cores of tumor composed of fibroblastic malignant cells producing lace-like osteoid matrix. Osteosarcomatous foci in other parts of the body were excluded by performing extensive physical examination, radiologic imaging, and biopsy. Hence, a primary osteosarcoma was diagnosed. The patient underwent portal vein embolization in preparation for a surgical resection of the right liver lobe. He was admitted six weeks after the embolization for dyspnea and abdominal distension and expired due to abdominal hematoma and pulmonary embolism. CONCLUSION: Based on the rarity, lack of consensus in treatment, and dismal prognosis, extraosseous osteosarcoma should be considered a separate entity from osseous osteosarcoma. More data and research are needed in this rare and understudied malignancy.