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.