[Bone complications from chronic etretinate intoxication in children]

Clinical, roentgenographic and biologic features of etretinate bone toxicity in a 13-year-old girl with pachyonychia congenita syndrome are reported. Etretinate is a synthetic derivative of vitamin A that infrequently induces bone and joint abnormalities in children. The following manifestations can be observed: cortical hyperostosis, pain, calcification of tendons, thinning of long bones, demineralization, premature closure of epiphyses, or abnormal remodelling. Onset of these anomalies is often delayed since etretinate has a long half-life. Mechanisms are unknown. We advocate use of the minimum effective dosage and regular monitoring of patients.