Abstract
Background : Myositis ossificans circumscripta (MOC) is a benign and self-limiting heterotopic ossification in the subcutaneous fat, tendons, muscles, and nerves. It is commonly due to trauma and is frequently encountered in the arm, shoulder, thigh, and hand which are prone to trauma. Non-traumatic MOC arising from the abdominal muscles is extremely rare.
Clinical presentation : This case report is of a 7-year-old male with a three-year history of progressive painless abdominal swelling in the left hypochondria region with no history of associated trauma. CT scan of the abdomen showed a well-defined hyperdense mass in the left external oblique muscle. Histological diagnosis confirmed myositis ossificans of the external oblique muscle. The mass was removed surgically with no immediate or late complications.
Conclusion : As non-traumatic myositis ossificans of the abdominal muscles are extremely rare, a CT scan plays a crucial role in differentiating it from other abdominal tumors.
Keywords ; Myositis ossificans circumscripta, Computed tomography scan, abdomen.