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.