https://youtube.com/shorts/-4GdaupT024
Plain Radiograph & CT Findings
1. Location & Distribution
- Medullary-based lesion
- Common in proximal femur, tibia, humerus
- Often centric, but can be eccentric
- Typically involves the diaphysis or metaphysis
2. Matrix Appearance (Key Feature)
- Ground-glass opacity
- Best appreciated on CT
3. Margins & Borders
- Well-defined borders
- No permeative or moth-eaten pattern
- Suggests a non-aggressive process
4. Endosteal Changes
- Smooth endosteal scalloping
- Reflects slow expansion
- No sharp or irregular cortical erosion
5. Cortex
- Cortical thinning and expansion may be present
- Outer cortical contour is smooth and intact
- No cortical breakthrough in typical cases
6. Rind Sign (Classic)
- Thick layer of sclerotic bone surrounding the lesion
- Seen as:
- Highly characteristic for fibrous dysplasia
7. CT-Specific Advantages
- Best modality to:
- Helps differentiate FD from:
Take-home Pattern
Ground-glass matrix + smooth endosteal scalloping + intact cortex + rind sign
→ Think fibrous dysplasia first
#FibrousDysplasia, #BoneCT, #PlainRadiograph, #GroundGlassMatrix, #RindSign, #MSKRadiology, #BoneLesions, #MusculoskeletalImaging, #RadiologyPearls, #BoneTumorDifferential, #Vibecase
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