Subungual exostoses.

From 1910 through 1975, forty-four patients with subungual exostoses were seen at the Mayo Clinic. Thirty-four of them had the exostosis on the great toe. Forty-three of the patients were treated by local excision and one was treated by amputation of the hallux. Five patients had local recurrence. None of the tumors underwent malignant change. Histologically, the tumors consisted of a proliferating fibrocartilaginous gap that merged into mature trabecular bone at its base. The growth in the cap was so active that is sometimes mimicked sarcoma, but no true anaplasia was seen. The subungual exostoses were uniformly benign, and local excision was the treatment of choice.