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Subungual Exostosis

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Other Names

  • Subungal Exostosis
  • Dupuytren’s exostosis

Background

  • This page refers to Subungal Exostosis (SE), a relatively uncommon benign bone tumor that occurs in the distal phalanges of the toes

History

  • First described by Dupuytren in 1817[1]

Epidemiology

  • There is a paucity of literature to describe the epidemiology
  • Location
    • 70-80% occur on the hallux[2]
  • Demographics
    • Average 18 of presentation is 26, 55% of cases occur in patients under age 18[3]
    • Generally thought to be more common in women (~2:1)[4]
  • Other
    • Accounts for 17% of surgeries performed on the great toe[5]
    • In one podiatry practice, SE accounts for 22.3% of patients with nail plate deformation[6]

Example of subungual exostosis[7]

Pathophysiology

  • General
    • Osteocartilaginous tumor of the distal phalanges of the foot
    • Patients typically present with pain, erythema, and deformity of the nail bed
    • Misdiagnosis and delayed diagnosis of this lesion are common
  • Finger
    • Rarely, this can occur in the phalanges of the upper extremity
    • Most commonly reported on the thumb

Etiology

  • General
    • Poorly understood
  • Proposed etiologies
    • Trauma
      • Most commonly accepted theory is reactive metaplasia resulting from microtrauma
      • However there is no definitive evidence to support a single pathogenesis[8]
    • Infection
    • Tumor
    • Hereditary abnormality
      • Linked to translocation t(X;6)(q22;q13-14)[9]
      • This implies it is a true neoplastic process rather than reactive response to trauma
    • Activation of a cartilaginous cyst

Histopathology

  • Subungal Exostosis
    • Histology: cartilaginous cap of exostoses is made of fibrocartilage[10]
    • Bone is formed directly from fibrous tissue
  • Subungual Osteochondroma
    • Some controversial whether this is the same disease
    • Histology: hyaline cartilage and is confluent with the underlying trabecular and cortical bone
    • Bone is derived from enchondral ossification

Associated Conditions

  • Multiple Hereditary Exostoses[11]

Risk Factors

  • Unknown

Differential Diagnosis


Clinical Features

  • History
    • Pain, erythema, and deformity of the nail bed
    • Patients endorse significant impact on quality of life
  • Physical Exam: Physical Exam Foot
    • Affected toe reveals a firm, fixed nodule with a hyperkeratotic smooth surface at the distal end of the nail plate
    • Location is typically dorsomedial mass
    • May see elevation and periungual ulceration and infection
    • Nail plate is often deformed
  • Special Tests

Evaluation

Bony projection at the great toe of a 10 year old consistent with Subungual Exostosis[12]

Radiographs

  • Standard Radiographs Foot
  • Findings
    • Pedunculated radiopaque mass on the dorsomedial surface of the distal phalanx.
    • Noncontinuity and continuity with the cortex are both described in the literature
    • May be described as a trabeculated pattern of cancellous bone with or without a defined cortex

MRI

  • Some physicians/ podiatrist consider it to be imaging modality of choice
    • Reason is due to the fibrocartilaginous component that is not radiographically apparent[13]

Classification

  • Not applicable

Management

Nonoperative

  • Indications
    • Unclear
  • Disease process is progressive, management is primarily surgical

Operative

  • Indications
    • Majority of cases
  • Technique
    • Marginal surgical excision

Rehab and Return to Play

Rehabilitation

  • No clear guidelines

Return to Play/ Work

  • No clear guidelines

Complications and Prognosis

Prognosis

  • Unknown

Complications


See Also


References

  1. Dupuytren GF. On the Injuries and Diseases of Bones, translated and edited by F Le Gros Clark, pp 408-411, Sydenham Society, London, 1847.
  2. Carroll RE, Chance JT, Inan Y. Subungual exostosis in the hand. J Hand Surg Br. 1992;17:569–574.
  3. Miller-Breslow A, Dorfman H: Dupuytren's (subungual) exostosis. Am J Surg Pathol 12: 368, 1988.
  4. Vázques-Flores H, Domínguez-Cherit J, Vega-Memije ME, et al: Subungual osteochondroma: clinical and radiologic features and treatment. Dermatol Surg 30: 1031, 2004.
  5. Pérez-Palma L, Manzanares-Céspedes MC, Veciana EG. Subungual exostosis. J Am Podiatr Med Assoc 2018;108:320–33. doi: 10.7547/17-102
  6. Gavillero A, Arxé D, de Planell E, et al: Estudio estadístico en cirugía ungueal. El Peu 25: 20, 2005.
  7. Image courtesy of MDedge.com, "Subungual Exostosis"
  8. Suga H, Mukouda M. Subungual exostosis. Ann Plast Surg. 2005;55:272–275.
  9. Dal Cin P, Pauwels P, Poldermans LJ, Sciot R, Van den Berghe H. Clonal chromosome abnormalities in a so-called Dupuytren’s subungual exostosis. Genes Chromosomes Cancer. 1999;24: 162–164.
  10. Ippolito E, Falez F, Tudisco C, Balus L, Fazio M, Morrone A. Subungual exostosis. Histological and clinical considerations on 30 cases. Ital J Orthop Traumatol. 1987;13:81–87.
  11. Stark JD, Adler NN, Robinson WH. Hereditary multiple exostoses. Radiology. 1952;59:212–215.
  12. Case courtesy of Dr Ayush Goel, Radiopaedia.org, rID: 74749
  13. Higuchi K, Oiso N, Yoshida M, et al. Preoperative assessment using magnetic resonance imaging for subungual exostosis beneath the proximal region of the nail plate. Case Rep Dermatol 3: 155, 2011
Created by:
John Kiel on 11 February 2022 05:21:10
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Last edited:
14 March 2022 11:09:55
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