Other tumors of bone
Subungual exostosis

Author: Nat Pernick, M.D. (see Authors page)

Revised: 17 October 2016, last major update June 2005

Copyright: (c) 2003-2016,, Inc.

PubMed search: Subungual [title] exostosis

Cite this page: Subungual exostosis. website. Accessed April 24th, 2017.
Definition / General
  • Also called Dupuytren’s exostosis
  • Rare, osteochondroma-like lesion under nail bed, usually of great toe
  • A type of myositis ossificans
  • Appears to be neoplastic based on t(X;6) present
  • Usually male teenagers / young adults
  • Painful, slow growing, may produce ulceration of nail
  • May be associated with local trauma, infection or chronic irritation
Radiology Description
  • Calcifying lesion projecting from distal phalanx
Radiology Images
Images hosted on PathOut server:

Distal phalanx of great toe

  • Simple excision, may recur, particularly with incomplete excision
  • Does not transform
Micro Description
  • Spindle cell proliferation on surface of cartilage, resembling a cap, with underlying trabecular bone formation
  • May be hypercellular and mitotically active
Micro Images
Images hosted on PathOut server:

Moderately cellular cartilage

Reactive bone

Images hosted on other servers:

19 year old woman with thumb lesion

Molecular / Cytogenetics Description
Differential Diagnosis
  • Osteochondroma: different location, no spindle cell proliferation
  • Sarcoma: marked atypia
Additional References