Subungual exostosis: diagnosis and treatment in children.

Subungual exostosis is a benign bone tumor of the distal phalanx occurring beneath or adjacent to the nail. The exostosis occurs most commonly in the toes, most frequently involving the distal phalanx of the hallux. The majority of the lesions occur in the second or third decade of life. From 1975 to 1995, 21 children were treated for subungual exostosis at the Children's Hospital of Eastern Ontario, 20 of whom underwent local excision. One patient required an amputation of the affected distal phalanx due to recurrence of the lesion. The subungual exostosis occurred on the hallux in 14 children, the second toe in three children, the third toe in two children, and the fourth toe in two children. No lesion was encountered in the little toe. The exostosis is very rare in patients under 7 years of age; the average age in this review being 12 years and 6 months. The lesion recurred in three children. Removal of the nail over the exostosis facilitates the mandatory entire removal of the lesion.