Nail unit enchondromas and osteochondromas: a surgical approach.

The anatomic singularities of the nail unit explain why bony tumors and osseous outgrowths of the distal phalanx quickly interfere with the nail apparatus. Osteochondromas (or exostosis) are benign osteocartilaginous outgrowths most commonly located on the hallux. They are by far the most common bony lesions affecting the nail unit. While frequently considered benign tumors, subungual exostoses are better regarded as reactional osseous outgrowths rather than true tumors. Enchondromas (better named chondromas) are intraosseous tumors whose location at the distal phalanx is rare. Large tumors may be responsible for phalanx deformity.