Intracortical osteosarcoma of the femoral neck mimicking osteoid osteoma: a case report

Intracortical osteosarcoma (ICOS) is a rare type of osteosarcoma, with only a few cases documented in the literature. ICOS can mimic benign lesions on imaging due to its slow progression and non-specific radiologic features, which may cause delayed diagnosis and late-stage presentation. We present an 18-year-old Middle Eastern male with ICOS of the femoral neck, who initially underwent radiofrequency ablation for a misdiagnosis of osteoid osteoma. The lesion was ultimately treated with wide resection and reconstruction using an allograft-prosthesis composite after it caused a pathologic fracture. In cases where treatment for osteoid osteoma is ineffective or a pathologic fracture occurs , the possibility of misdiagnosed intracortical osteosarcoma should be considered.