This is one of the more common bony lesions of the foot. It is a benign tumor of bone and cartilage. It is generally found underneath the toenail and may press upwards resulting in deformity of the nail plate and/ or soft tissues. In severe lesions, the overlying tissues may ulcerate and become infected. This lesion responds well to surgical excision, and rarely reoccurs.



  • Deformity and separation of the nail plate, expansion of the soft tissues
  • Direct pressure on the nail may be painful
  • Aggravated by wearing tight shoes.
  • There may be signs of ulceration and infection.


  • Cause is unknown, but believed to be trauma

What you can do

  • Consult a podiatrist or physician
  • Avoid tight fitting foot wear
  • If an infection develops soak the foot in a basin of warm water two or three times a day. Contact your podiatrist or physician immediately.
  • Abnormal growths and infections require prompt professional attention.

What the doctor may do

  • Take x-rays or perform other imaging to establish a correct diagnosis.
  • If the toenail is causing problems, it may be removed
  • Treat any infection present with antibiotics
  • Surgically remove the exostosis
  • Completely remove a deformed toenail so it will not grow back.

Other conditions resembling a Subungual Exostosis

  • Other, more serious, bone tumors may resemble an exostosis.
  • Evaluation by a trained practitioner is essential
  • An infected ingrown toenail may resemble an ulceration from an exostosis
  • Chronic in-growing nails can cause deformity of the nail plate and/or surrounding soft tissues.