Cortical desmoid

Dr David Dang et al.

Cortical desmoids, also known as cortical avulsive injuries or the Bufkin lesion, are a benign self-limiting entity. This is a classic "do not touch" lesion, and should not be confused with an aggressive cortical/periosteal process (e.g. osteosarcoma). 

Epidemiology

It typically presents in adolescents (10-15 years of age). There may be a male predilection. 

Clinical presentation

Patients are usually asymptomatic, and it is discovered incidentally. Occasionally pain may be present.

Pathology

It is related to repetitive stress at the attachment of the medial head of gastrocnemius or distal adductor magnus at the posterior medial aspect of the distal femoral metaphysis.

Location

Cortical desmoids are seen at the posteromedial aspect of the distal femur. They can be bilateral in approximately one-third of cases.

Radiographic features

Radiograph

Typically shows a saucer-shaped radiolucent cortical irregularity involving the posteromedial aspect of the distal femoral metaphysis at the attachment of the adductor magnus tendon. The lesion lacks an outer margin.

MRI

Defines anatomy much better and is seen as a cortically based lesion in the expected location (i.e. posteromedial distal femoral metaphysis) 3,4:

  • T1: low signal
  • T2: high signal and surrounding low signal rim may be present
  • T1 C+ (Gd): most show enhancement
Nuclear medicine

On bone scan, there is an abnormal increase in activity because of the chronic stress/traumatic origin of this lesion.

Differential diagnosis

Imaging differential considerations include

Practical points

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Article Information

rID: 5198
Section: Pathology
Synonyms or Alternate Spellings:
  • Distal femoral cortical irregularity
  • Distal femoral cortical irregularity (DFCI)
  • Avulsive cortical irregularity of the distal femur
  • Distal femoral cortical defect
  • Periosteal desmoid
  • Cortical desmoids
  • Bufkin lesion
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    AP femur X-ray
    Case 1: with concurrent healing fibrocortical defect
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    Axial T2 of the l...
    Case 2
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    Case 3
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    Case 4
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