[Multiple hyperostosis with unilateral sacroiliitis. A new spondyloarthropathy].

Six patients (4 male and 2 female) presenting with an original, predominantly osseous disease are reported. The disease is characterized by a chronic inflammatory process affecting the thorax, the spine, the femur in 1 case and in all patients only one of the sacro-iliac joints. The condition had begun 11 to 28 years previously and had been active for 6 to 24 years. One case started with regressive polyarthritis. There was no visceral involvement. Radiograms showed bone condensation with hyperostosis, sometimes hypertrophic, unrelated to any articular space. Depending on each patient, the lesions involved the clavicles, the sternum, the posterior arch of the ribs, the vertebrae, the inferior femoral metaphysis. The only joints involved were the sacro-iliac and anubrio-sternal joints. The areas affected showed high radioisotope uptake. There was discrete biochemical inflammatory syndrome. Three of the 6 patients belonged to the HLA group B 27. The multiple biopsies performed showed no specific lesions. The disease proceeds by successive attacks lasting several months and responding poorly to anti-inflammatory drugs. One patient developed Crohn's disease, another, retroperitoneal fibrosis. In some respects, this condition is remindful of sterno-clavicular hyperostosis and of the osteo-arthropathy in palmoplantar pustulosis or acne conglobata. It seems to constitute a new variety of spondylo-arthropathy intermediate between the above-mentioned diseases and genuine ankylosing spondylitis.