Sousan Kolahi, Mojtaba Varshochi, Sepideh Tahsini Tekantapeh, Mohammad Mahdi Tehrani Ghadim, Amirreza Jahanshahi
A 42-year-old male amateur football player presented with a 17-day history of progressive groin pain, primarily on the right, radiating to the perineum, associated with limitation of hip motion. Because of proximal weakness and elevated inflammatory markers, polymyositis and an infectious process were initially suspected. Electromyography demonstrated a subacute incomplete axonal lesion of the right femoral nerve likely due to iliopsoas compression. Joint aspiration yielded purulent-appearing fluid with 850 WBC/mm3 and 80% PMNs, although cultures remained negative. MRI demonstrated bone marrow edema at the pubic symphysis, fluid collections in the adductor and iliacus muscles, right iliopsoas bursitis, and mild hip effusion, supporting a diagnosis of osteitis pubis with associated inflammatory myositis and bursitis rather than primary infection or polymyositis. Empirical antibiotics and corticosteroid therapy resulted in clinical and laboratory improvement. This case highlights the diagnostic challenge of osteitis pubis presenting with femoral neuropathy and inflammatory findings that may mimic infectious or inflammatory myopathy.