Early skeletal hyperostoses secondary to 13-cis-retinoic acid.

Prolonged therapy with retinoid drugs (chemically similar to vitamin A) often results in skeletal hyperostoses, similar to those seen in idiopathic skeletal hyperostosis. Eight patients, aged 5-26 years, with dermatologic disorders were treated with 13-cis-retinoic acid. Skeletal surveys were obtained before and during treatment. In 1 year, six of the eight patients had developed such skeletal hyperostoses in both axial and appendicular regions. The cervical spine was the most common site of involvement. None of the children demonstrated accelerated skeletal maturation. Two of the patients had mild musculoskeletal discomfort during this period. The findings indicate that high-dose 13-cis-retinoic acid therapy may cause skeletal hyperostoses, requiring radiographic monitoring during prolonged periods of treatment. An implication of these observations, relating to the etiology of idiopathic skeletal hyperostosis, is discussed.