Nonossifying fibromas

The commonest fibrous lesion of bone is the fibrous cortical defect and the histologically identical but larger nonossifying fibroma. Both lesions are seen in childhood and adolescence, slightly more common in boys, with a predilection for the long bones around the knee. Fibrous cortical defects are seen in up to 30% of the normal population under the age of 15 years and... 

Fig. 21.9. Nonossifying fibroma. Well defined eccentric lytic lesion with a spiral fracture extending up the tibial diaphysis...

Arata MA, Peterson HA, Dahlin DC (1981) Pathological fractures through nonossifying fibromas. J Bone Joint Surg Am 63A 980-988... 

A sclerotic border of a bony lesion is more obvious with MDCT than with radiograms. The presence or absence of such a sclerotic border may allow narrowing the differential diagnosis. Chondroblastomas, nonossifying fibromas, and fibrous dysplasia typically are surrounded by a sclerotic rim, while eosinophilic granulomas and osteolytic metastases are not (Fig. 35.8 Gould et al. 2007). 

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