Genu varum deformity due to premature epiphyseal closure after treatment with isotretinoin for neuroblastoma: A case report

Isotretinoin, a vitamin A derivative, is known to induce premature epiphyseal closure. We report the case of a 9-year-old boy with neuroblastoma who demonstrated premature epiphyseal closure after 1 year of isotretinoin treatment (72.3 mg/m2/day). A bone bridge developed on the bilateral proximal tibial growth plate resulting in genu varum. We performed hemiepiphysiodesis on the bilateral proximal tibia in anticipation of the spontaneous resolution of the bone bridge. Genu varum on the left side was corrected with the resolution of bone bridge. For the remaining bone bridge on the right side, arthroscopy-assisted physeal bar resection was performed, and genu varum on the right lower extremity was also corrected. A regular review of the alignment of the upper and lower limbs is necessary to provide timely intervention in patients using isotretinoin, considering the possibility of premature epiphyseal closure.