18F-FDG PET/CT in Isolated Primary Extraskeletal Osteosarcoma.

Extraskeletal osteosarcoma is a rare, high-grade soft tissue malignancy, accounting for approximately 1% of all soft tissue sarcomas. Despite the histologic resemblance to osteogenic osteosarcoma, it is considered as a distinct entity because of the differences in clinical behavior and response to treatment. Hence, imaging plays a vital role in establishing the nonskeletal origin of the tumor, differentiating it from osteogenic osteosarcoma. We present F-FDG PET/CT findings in a case of isolated primary extraskeletal osteosarcoma confirmed on histopathology.