Fibrous cortical defect

Case contributed by Dr Andrei Tsoriev

Diagnosis almost certain

Presentation

Non specific knee pain in female amateur dancer

Patient Data

Age: 9

Gender: Female

From the case: Fibrous cortical defect

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Coronal non-contrast

Right tibial cortical bone shows well circumscribed lucency without destruction/soft-tissue mass.

Case Discussion

Cortical fibrous defect also known as "non-ossifying fibroma" is the most frequent bone lesion in children, occurring in up to 30-40% of children.Most commonly seen in adolescents. No histologic difference exists between non-ossifyinf fibromas and cortical fibrous defects. Most large lesions called nonossifying fibromas (NOF), smaller ones - cortical fibrous defects, basicly the terms FCD and NOF are interchangeable. Most authors believe these to be the same entity. These lesions are developmental abnormalities opposed to tumours. They are usually incidental findings on x-rays, small ones have no clinical significance, large ones may result in fracture, considered pathological.CFDs may be multiple.

In this case FCD is for sure an incidental finding having pathognomonic visual features. Biopsy, intervention and surgery in such lesions should be avoided as well as followup imaging.