Metaphyseal fibrous defect

Metaphyseal fibrous defect
	Diagnosis in short
Synonyms	nonossifying fibroma, fibrous cortical defect, fibrous metaphyseal defect, fibroxanthoma of bone
LM DDx	giant cell tumour of bone
Site	metaphysis of bone - usu. lower extremity
Clinical history	incidental radiograhic finding
Prevalence	common
Radiology	lucent defect
Prognosis	benign
Treatment	none

Metaphyseal fibrous defect, abbreviated MFD, is a common benign abnormality of the metaphysis, classically seen in children and young adults.

They are also known as fibrous cortical defect, fibrous metaphyseal defect, and fibroxanthoma of bone. Nonossifying fibroma is a larger lesion but otherwise identical.

General

Common.
Non-neoplastic.
Self-limited.
Skeletally immature individuals, children and adolescents.
Often small lesions discovered as an radiographic incidentaloma.
Rarely seen as a pathologic specimen (should not be biopsied).
May be seen in the context of Jaffe-Campanacci syndrome.^[1]

Clinical history:

Incidental radiographic finding.
Pathologic fracture.

Prognosis:

Ideally should not be biopsied.
Radiographically characteristic and benign.
Ideally should not be treated or even biopsied.
Spontaneously resolve by ossification.
May resolve into a 'bone island'.

Site

Metaphysis of distal femur or proximal tibia (80%).
Cortical.
Metaphysis.
Long bones.
Eccentric location.

Gross

Firm, granular, brown to yellow to red.

Microscopic

Features:

Spindle cells without cytologic atypia are arranged in a storiform pattern.
Scattered chronic inflammatory cells and benign giant cells.
Foam cells and hemosiderin deposition are present.
Mitoses are seen but cytologic atypia is absent.

DDx (microscopic):

Giant cell tumour of bone - epiphyseal location, occurs in adults.

Relevant Diagnostic Groups

Clinical
- FOG MACHINES - acronym for radiographically lytic bone lesions ^[2]
- 'Skeletal do not touch list' ^[3]
Pathologic
- Giant cell lesions of bone.
- Spindle cell lesions of bone.

Images

Metaphyseal fibrous defect - intermediate magnification.
Metaphyseal fibrous defect - high magnification.

www:

Stains

Not relevant.

IHC

Not relevant

Molecular

Not relevant

Radiographic findings

Sharply demarcated, lucent, loculated, meta-diaphyseal lesion surrounded by a rim of sclerotic bone

Sign out

BONE, CURETTAGE: METAPHYSEAL FIBROUS DEFECT / NONOSSIFYING FIBROMA.

References

↑ URL: http://www.bonetumor.org/plasma-cell-tumors/jaffe-campanacci-syndrome. Accessed on: October 14, 2014.
↑ URL: http://radiopaedia.org/articles/lytic-bone-lesion-mnemonic. Accessed on: October 14, 2014.
↑ URL: http://radiopaedia.org/articles/skeletal-do-not-touch-lesions-1. Accessed on: October 14, 2014.

External links

[1] URL: http://www.bonetumor.org/plasma-cell-tumors/jaffe-campanacci-syndrome. Accessed on: October 14, 2014.

[2] URL: http://radiopaedia.org/articles/lytic-bone-lesion-mnemonic. Accessed on: October 14, 2014.

[3] URL: http://radiopaedia.org/articles/skeletal-do-not-touch-lesions-1. Accessed on: October 14, 2014.

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