Bone & joints
Other chondrogenic tumors
Subungual exostosis
Author: Nat Pernick, M.D.
Topic Completed: 1 June 2005
Minor changes: 14 September 2021
Copyright: (c) 2003-2019, PathologyOutlines.com, Inc.
PubMed search: Subungual [title] exostosis
Table of Contents
Definition / general | Radiology description | Radiology images | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Pernick N Subungual exostosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bonesubungualexostosis.html. Accessed October 24th, 2021.
Definition / general
- Also called Dupuytren 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
Distal phalanx of great toe
Treatment
- Simple excision, may recur, particularly with incomplete excision
- Does not transform
Microscopic (histologic) description
- Spindle cell proliferation on surface of cartilage, resembling a cap, with underlying trabecular bone formation
- May be hypercellular and mitotically active
Microscopic (histologic) images
Moderately cellular cartilage
Reactive bone
Molecular / cytogenetics description
- t(X;6) (Am J Surg Pathol 2004;28:1033)
Differential diagnosis
- Osteochondroma: different location, no spindle cell proliferation
- Sarcoma: marked atypia
Additional references
