Nonossifying Fibroma




Fibroxanthoma, Metaphyseal Fibrous Defect


CLINICAL SUMMARY


Nonossifying fibromas are most commonly discovered incidentally near the ends of growing bones in children and adolescents. Most lesions spontaneously ossify by skeletal maturity, but large lesions can be symptomatic and require surgery.


DIAGNOSTIC FEATURES





















History


  • Children and adolescents



  • Most frequently an asymptomatic, incidental finding



  • Large, mostly lytic lesions may present with weight-bearing pain

Location


  • Metaphyseal, eccentric



  • Lesions in small bones, flat bones, and fibula may not appear eccentric



  • Distribution: most common about knee (55%)

Margins


  • Geographic lysis, sclerotic border



  • Lobulated contour, expanded and thinned cortex

Matrix


  • Variable mineralization, more visible after ossifying




IMAGING

























  • Nonossifying fibromas with typical eccentric, metaphyseal location seen in two distal femoral lesions ( left and right ).



  • Note cortical expansile remodeling, consistent with an indolent lesion ( left ).



  • Geographic lysis with sclerotic margins and lobulated contours are seen in both lesions.





Get Clinical Tree app for offline access