The SAPHO syndrome: Clinical and radiological differentiation and classification on the basis of 86 cases

Synovitis (inflammatory arthritis), acne (pustulosa), pustulosis (psoriasis , palmoplantar pustulosis), hyperostosis (acquired), and ostitis (bland ost eomyelitis) are symptoms forming the acronym SAPHO, which is a syndrome of nosologic heterogeneity. All entities forming the SAPHO syndrome are connec ted by a non-obligate dermato-skeletal association with an aseptic pustulou s character. 86 cases were analyzed clinically, radiologically and by histology/histopat hology. 31 adult patients showed the typical triad of pustulosis palmo-plan taris (psoriatica, PPP), sterno-costo-clavicular hyperostosis (SCCH), and " productive" spondylopathy, which we define as entity I: spondarthritis hype rostotica pustulopsoriatica (Spond.hyp.pp). Twelve adolescent and 13 adult patients showed entity no. II: chronic recur rent multifocal osteomyelitis (CRMO), being characterized by non-purulent o steomyelitis of plasma-cell sclerotic type, potentially being a reactive in flammatory process. 50% of the adult patients with CRMO showed PPP. Differe ntiation between these two entities is possible by detection of ossifying e nthesiopathy in cases of Spend. hyp.pp and primarily chronic ostromyelitis in cases of CRMO. Two more entities or abortive forms of group I and II are III: the inflamma tory syndrome of the anterior chest-wall (ACW syndrome) and IV: the more pr oductive form of isolated sterno-costoclavicular hyperostosis (SCCH). Both are connected quite frequently to HLA-B27-independent forms of spondarthrit is and to pustulous dermatosis. More rarely we find osteo-articular symptom s in cases of acne pustulosa, which form group V: acne-associated spondarth ritis and CRMO in the case of acne. Adult forms of CRMO with different forms of appearance (lumo-sacro-iliac hy perostosis with retroperitobeal fibrosis. pelvic type with affection of the hip-joint) are described. The immunologic theory of a "reactive osteomyeli tis" potentially triggered by saprophytes is described. The inverse acne tr iad is brought in a context of skin symptoms. A case of intercurrent postpa rtum symptoms together with ulcerative colitis is described. Three cases of patients with Crohn's disease are described. Clinical features, radiological findings, and histopathological elements ar e brought together to determine the connections between the different entit ies and the possibilities of differentiation. With these elements together with bone-scan, it is often not necessary to obtain a bone specimen. Therapeutical possibilities, especially concerning CRMO, are discussed. "SAPHO syndrome" is more a sign-post on the way to a more subtle diagnosis when it comes to hyperostotic, skin-associated diseases, and it needs inter disciplinary work to clear the situation.