Osteoid osteoma of the femoral neck as a rare cause of hip pain in a 50-year-old male: A case report.

Osteoid osteoma (OO) is a benign osteoblastic tumor typically affecting young individuals. OO arising in the femoral neck is rare and may present with atypical clinical and radiological features, frequently leading to diagnostic delay. We report a case of a 50-year-old man with persistent hip pain for 8 months. Initial radiographs were unremarkable, and both magnetic resonance arthrography (MRA) and magnetic resonance imaging (MRI) demonstrated nonspecific bone marrow edema without identification of a nidus. Despite multiple clinical evaluations, including diagnostic injections and lumbar spine imaging, the patient's symptoms persisted. Computed tomography (CT) ultimately revealed a small nidus with central mineralization in the anteromedial region of the femoral neck. The diagnosis was confirmed histologically, and the patient was successfully treated with CT-guided radiofrequency ablation (RFA), resulting in complete symptom resolution. This case highlights the diagnostic challenges of OO in the femoral neck, particularly in older patients with atypical symptoms. MRI may obscure the nidus due to extensive bone marrow edema, emphasizing the importance of CT in cases of persistent focal bone marrow edema and inconclusive MRI findings.