Osteochondroma-like parosteal osteosarcoma

Parosteal osteosarcoma is a well-differentiated, predominantly fibro-osseous variant of osteosarcoma, accounting for 5 of all osteosarcomas. We report a case of parosteal osteosarcoma in the metaphyseal area of right femur, of 2 years duration in a male aged 35 years. It was mistaken for osteochondroma in the initial biopsy, and the possibility of bizarre parosteal osteochondromatous proliferation (BPOP) was also considered. Subsequent excision of the tumor showed it to be a parosteal osteosarcoma. The patient had recurrence of the lesion after 1 year, and he attended a cancer institute. Follow-up showed metastases of the tumor on bone scan.