Extraskeletal Osteochondroma of the Great Toe in a Teenager.

Osteochondromas are common, benign surface tumors of bone, composed of the cartilage-capped bone confluent with the medullary canal of the metaphyseal bone. Extraskeletal osteochondromas have the same gross appearance and histologic characteristics as a typical osteochondroma but do not have any boney attachment to the surrounding osseous structures. They are rare and most frequently reported in the middle-age and older adults. We present the first case of an extraskeletal osteochondroma of the foot reported in a teenager. Our patient was a 17-year-old male complaining of a slow-growing mass along the medial border of the great toe that he first noted at the age of 14 years. The increasing size of the mass and frequency of complaints with shoe wear prompted medical attention. Imaging studies showed an ossified 1-cm boney mass with trabecular detail, located on the medial aspect of the great toe at the level of the interphalangeal joint, without any connection to the surrounding structures. An excisional biopsy revealed a well-circumscribed, easily removable mass, which proved to be an extraskeletal osteochondroma both clinically and histologically.