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metaphyseal fibrous defect

Monday 9 March 2009

Definition: Eccentric, sharply delineated, metaphyseal lesion in long bones of adolescents. It can be considered as a variant of the lesional group associating fibrous cortical defect (FCD), non-ossifying fibroma (NOF) or and benign fibrous histiocytoma of bone (BFHB).

It can be associated with adamantinomas of long bones.

Nota bene: This lesion is called non-ossifying fibroma or benign fibrous histiocytoma if mass-forming and involving the medullary cavity.

Clinical Features

- Adolescents
- Few or no symptoms except pain
- Usually found incidentally on radiography
- Fractures can occur through the thinned cortex1


- Controversy regarding whether neoplastic or developmental aberration at epiphyseal plate


- usually long tubular bones, particularly: upper or lower tibia, lower femur


- Granular and brown or dark red
- Eccentric
- Sharply delimited
- sharp delineation
- sclerotic margins
- Not too distant from epiphysis
- Sometimes accompanied by epiphyseal disorders


- Cellular masses of fibrous tissue
- often storiform pattern
- spindle cell of fibroblastic appearance
- irregularly scattered osteoclasts.
- Frequent scattered osteoclasts and collections of foamy and hemosiderin-laden macrophages
- Exceptionally, bizarre nuclear features, not necessarily indicative of malignant


- When loose and with an intramedullary component, designated non-ossifying fibroma or non-osteogenic fibroma

Differential Diagnosis

- giant cell tumor of bone
- malignant fibrous histiocytoma
- aneurysmal bone cyst
- chondroblastoma