Ischium: A Rare Location for Osteoid Osteoma

Abstract

Background: Osteoid osteoma is a benign osteoblastic tumor of unknown etiology constituting 10-12% of benign bone tumors. Pelvic involvement has been described mostly in acetabulum. Case Report: 42 years old male patient presented with history of fall and pain in right hip region. X-ray showed a well-circumscribed lytic lesion with central rounded radiolucent nidus in the right ischial tuberosity with surrounding bone sclerosis. Conclusion: Osteoblastoma is a distinct benign tumor to be considered as a differential. Ischial tuberosity is a rare location for osteoid osteoma. This unusual location for this tumor combined with altered clinical symptoms leads to late diagnosis.