Cortical hyperostosis and enthesopathy due to long-term etretinate administration

Two cases are presented which show a severe ossification disorder that we observed during long-term administration of a synthetic vitamin A analogue (etretinate). The radiologic findings are discussed in relation to the skeletal abnormalities, which occur in chronic vitamin A intoxication and retinoid hyperostosis, which has been recently described in the literature as a side effect of another retinoid (isotretinoin).