MSK essentials

SAPHO syndrome

16-year-old female with pain for 3 months on the sternum, between the shoulder blades and low in the back. High intensity of pain in the morning and at rest.

Examination findings

Pressure pain can be induced at the sternum and in the middle of the thoracic spine. The spine is less mobile. There is a psoriatiform scaly skin lesion on the right lower leg. ESR is elevated 20/44 mm, mild iron deficiency anemia, other laboratory values in the normal range, negative are HLA-B27, RF, ANA, ENA, dsDNA-AK, p/s-ANCA and ACE.

SAPHO syndromeImaging findings

  • MRI shows radio-occult lesions on BWK 4 and 11 as well as LWK 1 and 5, with contrast-enhancing foci on the ventral edges of the vertebral body, surrounded by bone marrow edema (“shiny corners”). Endplate impression of BWK 4.

  • Band-shaped osteolysis at the csternal body with irregularly limited marginal sclerosis.

  • Sacroiliacal joints are morphologically unremarkable.

Together with the psoriatiform skin efflorescence, the radiologic findings are regarded as SAPHO syndrome. The differential diagnosis includes chronic recurrent multifocal osteomyelitis (CRMO).

Therapy and course

Initially NSAID therapy (up to max. 3x800mg/day ibuprofen) for 6 weeks, then therapy with sulfasalazine for 4 ½ months, gradually tapering off. Complete remission occurs after six months. The patient has been symptom-free for 3 ½ years and has returned to competitive sport.

SAPHO syndrome in the follow-upBackground information

The acronym “SAPHO” describes the main symptoms “synovitis”, “akne”, “pustulosis”,“hyperostosis” and “osteitis”. The abbreviation “Skibo disease” (skin and bone) is also derived from the heterogeneous coexistence of skin and bone findings. The diagnostic criteria are: 1. multifocal, sterile osteomyelitis without or with pustular skin disease, 2. arthritis and pustular dermatosis, 3. osteomyelitis and pustular dermatosis or psoriasis.

The following SAPHO syndromes are distinguished: 1. chronic recurrent multifocal osteomyelitis (CRMO) in two thirds of cases, 2. spondylarthritis hyperostotica pustulopsoriatica in almost one third of cases (pustulosis palmoplantaris, sternoclavicular hyperostosis, spinal lesions) and 3. rare abortive forms (ACW syndrome = anterior chest wall syndrome, SCCH = extended sternoclavicular hyperostosis, acne CRMO, acne spondylitis).

Chronic recurrent multifocal osteomyelitis (CRMO) usually manifests itself outside the SAPHO syndrome with synchronous or metachronous osteomyelitis, preferably on the metaphyses of the long bones, the thoracolumbar vertebral bodies and the clavicles. Pustulosis palmoplantaris is present in 60% of cases. Pathogens cannot usually be isolated; anaerobic and hypovirulent skin germs are discussed as the cause.

Whether SAPHO syndrome should be classified as a seronegative spondyloarthropathy is the subject of controversial debate. This arthropathy group includes the following entities: 1. ankylosing spondylitis (Bechterew's disease), 2. psoriatic arthropathy, 3. enteropathic arthritis (Crohn's disease, ulcerative colitis), 4. reactive (post-infectious) arthritis and 5. undifferentiated spondyloarthropathies.

Learning points

In the case of multilocular joint and spinal foci, the medical history should be extended to include evidence of skin affections. Inflammatory manifestations in the skeletal system are often detected earlier in MRI than in radiography. Radiology plays an important role in the early and correct diagnosis of inflammatory systemic diseases.