The SAPHO syndrome: defining the radiologic spectrum of diseases comprising the syndrome

The objective of our study was to clarify the radiologic spectrum of disease entities belonging to the SAPHO syndrome (SAPHO being an acronym for synovitis, acne, pustulosis, hyperostosis, and osteitis). A retrospective analysis of radiologic data was undertaken to determine the relationship of the osteoarthritic changes seen in palmoplantar pustulosis (PPP, n = 179), acne (n = 3), psoriasis vulgaris (PsV, n = 355), generalized pustular psoriasis (GPP, n = 25), and chronic recurrent multifocal osteomyelitis (CRMO, n = 4). Osseous changes of PPP, acne, and CRMO overlap each other; 7 PPP, 2 acne, and 3 CRMO patients manifested stenocostoclavicular hyperostosis as well as hyperostosis of the spine, pelvis, and/or femur. These findings were not seen in either PsV or GPP patients. Thirteen PsV and 4 GPP patients had peripheral arthritis and/or symmetrical sacroiliitis, which were not observed in the PPP, acne, and CRMO patients. The PPP, acne, and CRMO patients may be grouped as belonging to the single disease entity, namely SAPHO syndrome. Our findings do not support the inclusion of PsV and GPP in the spectrum of this syndrome.