Subungual Exostosis

The terms subungual refers to something that is underneath the nail on the toes or fingers. The term exostosis refers to an overgrowth of bone. This can also be called a bone tumor. The great majority of which are benign. So a subungual exostosis is an overgrowth of bone underneath the nail. These overgrowths of bone are usually very small but can be painful when walking or wearing tight shoe gear.

The subungual exostoses can also cause deformity in the nails. When the bone grows directly towards the nail and disrupts the nail bed, the nail itself will grow in a deformed manner. The nail usually appears to have a ridge in it. In some cases even if the exostosis is removed the damage to the bed of the nail persists leaving the ridge in the nail.

Depending on the location of the exostosis it may be difficult to see under normal x-rays. Sometimes special x-rays that accentuate the toe with the exostosis need to be taken. Upon diagnosis of the exostosis the question becomes whether to remove it or leave it alone.

As stated before the great majority of these bony overgrowths are benign. If the bony overgrowth was malignant it would have certain characteristics, such as, rapid growth. They would also have a different appearance then the normal benign overgrowth. For this reason removal of the bony exostosis is not always recommended. If the problem is purely cosmetic and the outgrowth is not severe, or causing pain then the removal is not warranted. As stated before removal of the exostosis does not always change the nail back to normal.

In cases where the exostosis is causing pain. A simple outpatient procedures can be performed to remove the exostosis. Often these involve cutting exostosis out and smoothing the bone. The recurrence rate is rather low.

When the exostosis is removed it is sent for evaluation to confirm that it is a benign growth. Following the procedure the patient will need to wear a special shoe for approximately 2 weeks. In some cases the nail has been damaged to the extent that it needs to be removed during the procedure.