[Sacroiliac changes, HLA-B27 negative, in primary hyperparathyroidism and osteomalacia].

Radiological sacroiliac (SI) changes were found in 3 patients, 2 with primary hyperparathyroidism (1 also with associated chondrocalcinosis) and 1 with osteomalacia. Osteomalacia was due to celiac disease. None of the 3 patients, all females, had a history of psoriasis, urethritis, iritis or chronic colitis. There was no renal function impairment. Peripheral joints were affected in the patient with associated condrocalcinosis. HLA B 27 was negative in all cases. Low back pain and vertebral stiffness were present in the patient with osteomalacia. A dramatic improvement in pain and stiffness ensued after vitamin D injections. These SI lesions, which may simulate ankylosing spondylitis, were attributable to subchondral bone changes related to the metabolic bone diseases. In the case of osteomalacia the SI lesions were predominantly on the right side, where there was a Looser's zone on the ischial ramus suggesting that pseudofractures could be a cause of SI changes. Metabolic osseous diseases such as osteomalacia or primary hyperparathyroidism should be investigated in cases of HLA B 27 negative radiological "sacroiliitis".