Subperiosteal Hematoma of the Iliac Bone: An Unusual Cause of Acute Hip Pain after a Fall.

BACKGROUND Subperiosteal hematoma (SPH) of the iliac bone is an extremely uncommon clinical entity that occurs mostly in young patients with a history of a recent fall or sports-related injury. Patients usually complain of severe hip pain after a fall, mimicking femoral neck fracture. CASE REPORT An 18-year-old female was transported to our hospital complaining of pain in her left hip after falling on her buttocks while engaging in martial arts. Ultrasound of her left iliac region revealed a subperiosteal mass on the internal aspect of the iliac bone lifting the iliac muscle. SPH of the iliac bone was suspected, which was also evident on pelvis and hip magnetic resonance imaging. Repetitive ultrasound did not reveal hematoma expansion. She was discharged from the hospital the next day without femoral neuropathy. CONCLUSIONS Physicians should be aware of our report, which highlights a patient with the rare clinical condition of SPH of the iliac bone occurring immediately after a fall. The differential diagnosis of acute hip pain, which mimics femoral neck fracture, should be considered in young patients. Ultrasound of the iliac region may be useful in detection and further management of SPH of the iliac bone.