[Pelvic type of chronic recurrent multifocal osteomyelitis]

We report about the juvenile and adolescent pelvic type of CRMO in 7 girls and 4 boys. The results show from solitary up to 7 pelvic lesions (average 3 lesions) predominantly in the acetabular and paraacetabular region (sometimes with hip joint effusion as a sign for concomitant coxitis).Tc99m-bone-scan is helpful to evaluate exactly the pattern of bone affection. We find 3 stages of an primarily chronic, non-purulent osteomyelitis going along with a "plasma-cell-sclerotic process", leading to a Garrè-type sclerosing end-stage, which probably heals after some years spontaneously, projecting on clinical symptoms and radiological appearance. The concomitant coxitis ("sympathetic coxitis") is clinically often in the foreground, but reversible. Pain in case of CRMO responds surprisingly well on medication with acithromycine. Knowing about CRMO in its different clinical appearances - especially concerning what we call "sympathetic coxitis" - can be a useful for pediatric rheumatologists and orthopedic surgeons, as well as MRI-focused radiologists and pathologists. Therapy might find a useful drug in acithromycine. In conclusion we d like to point out, that CRMO is one entity under the "roof" of the so called SAPHO-syndrome, which again shows us, that SAPHO-syndrome ist not a diagnosis itself but more a sign-post on the way to a correct diagnosis.