Osteochondromas are benign bone tumors that form in the bone below the toenail. Developing mostly in children and young adults, osteochrondromas account for about half of all benign bone tumors. Unless they cause irritation to the surrounding tissue, they are usually not painful.
Osteochondromas may cause a deformity in the toenail or lead to an ingrown toenail, however. When suspect, osteochondromas may be removed surgically. In some instances they can return after the procedure.