A 19-year-old woman presented with a 3-month history of an enlarging lesion on the proximal aspect of the femur. After imaging studies and a biopsy had been performed, the mass was determined to represent heterotopic ossification (HO). The only known risk factor was a history of concussion. The mass was resected and, as of the 12-month follow-up, had not recurred.Conclusion:
HO is a potentially serious complication of ossification in soft tissues that can develop secondary to several disease states; it commonly occurs following traumatic brain injury. To our knowledge, this is the only case report that describes HO associated with a concussion and no other risk factors.