A retrospective study of bone changes in adults treated with etretinate.

Ninety patients aged 17 to 80 years were treated with etretinate for disorders of keratinization and were studied for bone changes. The treatment lasted from 0.1 to 7.9 years, mean 2.4 years. The average dosage of etretinate was 0.57 mg/kg/day (range 0.21 to 1.32 mg/kg/day), and the total dose was 31 gm (range 1 to 197 gm). Standard radiographs of the axial and peripheral skeleton were evaluated. The films of 44 patients showed skeletal abnormalities such as periosteal thickening, hyperostosis of the vertebral column, disk degeneration, osteoporosis, calcification of the spinal ligaments, and slender long bones. The present data indicate that the risk of skeletal disorders in adults treated with etretinate is significant (44 of 90), but that the severity of changes is minor.