Extraspinal Tendon and Ligament Calcification Associated with Long-Term Therapy with Etretinate

Abstract

Isotretinoin, a synthetic retinoid that has been prescribed for over 500,000 patients with cystic acne, has been associated with both spinal hyperostoses and a disorder similar to diffuse idiopathic skeletal hyperostosis. We describe a syndrome of tendon and ligament calcification, primarily in extraspinal locations, that we have observed after long-term therapy for psoriasis and disorders of keratinization with etretinate, another synthetic retinoid.