Cortical desmoids, also known as cortical avulsive injuries, are a benign self limiting entity. This is a classic 'don't touch' lesion, and should not be confused with an agressive cortical/periosteal process (e.g. osteosarcoma).
It typically presents in adolescents (10-15 years of age). There may be a male predilection.
Patients are usually asymptomatic and it is discovered incidentally. Occasionally pain may be present.
It is related to repetitive stress at the attachment of the adductor magnus aponeurosis at the medial posterior aspect of the distal femoral metaphysis.
It is seen at the posterior aspect of the distal femur. Can be bilateral in approximately one-third of cases.
Typically shows a saucer-shaped radiolucent cortical irregularity involving posteromedial aspect of the distal femoral metaphysis at the attachment of the adductor magnus tendon. The lesion lacks an outer margin.
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
On bone scan there is an abnormal increase in activity because of the chronic stress/traumatic origin of this lesion.
Imaging differential considerations include
- cortical desmoid is one of the skeletal “don’t touch” lesions
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- 2. Geoffrey S. Goodin, Clinical Observations, PET/CT Characterization of Fibroosseous Defects in Children: 18F-FDG Uptake Can Mimic Metastatic Disease, AJR 2006; 187:1124-1128
- 3. Suh JS, Cho JH, Shin KH et-al. MR appearance of distal femoral cortical irregularity (cortical desmoid). J Comput Assist Tomogr. 20 (2): 328-32. J Comput Assist Tomogr (link) - Pubmed citation
- 4. Yamazaki T et.al, MR findings of avulsive cortical irregularity of the distal femur, Skeletal Radiol. 1995 Jan;24(1):43-6.
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Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Distal femoral cortical irregularity||✓|
|Distal femoral cortical irregularity (DFCI)||✗|
|Avulsive cortical irregularity of the distal femur||✗|
|Distal femoral cortical defect||✗|