Presentation
Progressive skeletal deformities since childhood.
Patient Data
Bizzare shaped osseous thick band is seen extending from the left antero-lateral aspect of L3 & L4 vertebral bodies down to the malrotated femoral lesser trochanter of the left femur.
Massive heterotopic ossification along the distal portion of the psoas muslce (from left lateral aspects of L3 and L4 vertebrae) down to the adjoining iliacus (where its shows fusion with the left iliac bone) and then along the course of the iliopsoas muscle down to its insertion at the femoral lesser trochanter (with trochanteric fusion also).
Irregular heterotropic ossification along the superficial aspects of the visualized portions of the erector spinae muscles.
Milder degrees of heterotropic ossifications at the visualized portion of the left quadratus lumborum muscle.
Subsequent left pelvic tilt is noted.
Case Discussion
These massive ectopic soft tissue ossifications are virtually diagnostic of fibrodysplasia ossificans progressiva (FOB), formerly known as myositis ossificans progressiva (MOP), which is a rare congenital disease of progressive ectopic ossification of soft tissues.