SAPHO syndrome

Overview
SAPHO syndrome is thought to comprise a spectrum of disorders that share some clinical, radiologic and pathologic characteristics. An entity known as chronic recurrent multifocal osteomyelitis (CRMO) was first described in 1972. Subsequently in 1978 several cases of CRMO were associated with clinical findings of palmoplantar pustulosis. Since then, a number of associations between skin conditions and osteoarticular disorders have been reported with a variety of different names including sternocostoclavicular hyperostosis, pustulotic arthro-osteitis, and acne-associated spondyloarthropathy. SAPHO was coined in 1987 and basically represents a spectrum of inflammatory osteitis which may or may not be associated with dermatologic pathology.

Definition

 * Synovitis
 * Acne -- commonly involving the face and upper back.
 * Pustulosis -- usually involving the palms of the hands and/or soles of the feet (palmo-plantar pustulosis).
 * Hyperostosis
 * Osteitis

Radiologic Findings
Anterior chest wall (most common site, 65-90% of pts): Hyperostosis, sclerosis and bone hypertrophy especially involving the sternoclavicular joint, often with a soft tissue component.

Above images demonstrate sclerosis and hyperostosis of the medial left clavicle (sternocostoclavicular hyperostosis), a very typical site of involvement in the SAPHO syndrome.

Spine (second most common site, 33% of pts): Segmental, usually involving the thoracic spine. 4 main presentations include spondylodiscitis, osteosclerosis, paravertebral ossifications, and sacroiliac joint involvement.

Long bones (30% of pts): usually metadiaphyseal and located in the distal femur and proximal tibia. It looks like chronic osteomyelitis but will not have a sequestrum or abscess.

Flat bones: mandible and ilium (10% of pts).

Peripheral arthritis has been reported in 92% of cases of SAPHO as well.

Children: There is a predilection for the metaphysis of long bones in the legs (tibia, femur, fibula), followed by clavicles and spine.

Treatment
Treatment of patients with SAPHO syndrome is based on clinical symptoms. Generally, treatment involves non-steroidal antiinflammatory drugs and corticosteroid medications (either in the form of topical creams, tablets, or by injection into the involved area). Topical cold applications may also help in affected areas. If unsuccessful, both sulfasalazine and methotrexate have been tried with mixed results.