Nonossifying fibroma

Incidental finding in 9 yof, left humerus

aka Fibrous Cortical Defect, Don't Touch Lesions

Benign, asymptomatic lesions which occur in the metaphysis of long bones. Thin sclerotic boarder, often scalloped, slightly expansile. Most common bone lesion before the age of 30, approximately 20% of children, with spontaneous regresssion.

On CT they may have an interruption of cortex which is replacement by fibrous tissue not fracture of destruction.

Differential Diagnosis

Fog Machines or Fegnomashic

• Fibrous dysplasia
• Osteoblastoma
• Giant cell tumor
• Metastatic disease and Myeloma
• Aneurysmal bone cyst
• Chondroblastoma, Chondromyxoid fibroma
• Hyperparathyroidism
• Infection
• Nonossifying fibroma
• Enchondroma, Eosinophilic granuloma
• Solitary bone cyst

Patient B

Patient B

Patient B

Patient C

Patient C

Patient C

Fibrous Cortical Defect

Nonossifying fibroma smaller than 2 cm.