Subungual Exostosis

Aetiology

  • Fibrocartilaginous exostosis occurring from distal phalanx of the big toe
  • May also occur in hand or lesser toes – rare
  • Many are actually osteochondromas with a hyaline cartilage cap

Clinical Features

  • Pain and breach of the nail
  • Inflammation and elevation around the medial nail fold (more common)
  • Often previously misdiagnosed as an ingrown toenail due to similar appearance

Differential Diagnosis

  • Ingrown toenail
  • Subungual melanoma or Squamous Cell Carcinoma (SCC)
  • Glomus tumor

Imaging

X-ray (XR)

  • Clearly shows exostosis

Management

  • Excision
  • Try to preserve nail fold and bed, but usually not possible
  • Often leads to an abnormally shaped nail
  • Recurrence rate: 10% despite complete excision
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