Extraspinal manifestations of diffuse idiopathic skeletal hyperostosis

DISH is a condition characterized by calcification and/or ossification of soft tissues, mainly entheses, ligaments and joint capsules. Its prevalence increases with age and, therefore, DISH is a relatively common entity in the elderly. The classical site of involvement is the spinal column with right anterolateral soft tissue ossification being the most characteristic feature. However, DISH is not limited to the spine, and may affect multiple peripheral sites independently. Extraspinal entheseal ossifications are common and observing their isolated presence may lead to the diagnosis of DISH. Furthermore, hypertrophic or atypical OA observed in joints usually not affected by primary OA has frequently been reported in DISH. Several metabolic derangements and concomitant diseases have been suggested to be associated with DISH including obesity, increased waist circumference, hypertension, dyslipidaemia, diabetes mellitus (DM), hyperuricaemia, metabolic syndrome and an increased risk for cardiovascular diseases. Witnessing the present increase in lifespan, obesity, DM and metabolic syndrome in the Western population, the prevalence of DISH should be expected to rise. In order to increase the awareness for DISH, this review focuses on the extraspinal features of the condition.