Osteofibrous dysplasia

Osteofibrous dysplasia is a rare benign condition that afflicits the long bones.

Osteofibrous dysplasia
Diagnosis in short
LM DDx	adamantinoma, OFD-like adamantinoma, fibrous dysplasia
Molecular	clonal chromosomal abnormalities
Signs	tibial swelling, bowing
Prevalence	rare
Radiology	lytic bone lesion
Prognosis	self limited
Other	may be related to adamantinoma
Clin. DDx	adamantinoma, fibrous dysplasia, metaphyseal fibrous defect, osteosarcoma
Treatment	observation

It is also known as ossifying fibroma of long bones and congenital osteitis fibrosa.

General

Features:

• Benign fibro-osseous lesion.
• Rare.

Alternate names.

• Congenital osteitis fibrosa.

Location:

• Cortex of the tibial diaphysis

Pathophysiology:

• May be either a clonal neoplastic lesion or a developmental dysplasia.
• May be related to adamantinoma

Presentation:

• Lower leg swelling.
• Pain.
• Tibial bowing

Radiology:

• Intracortical lytic lesion.
• Surrounding zone of sclerosis.
• Seldom progresses radiologically.

Clinical DDX:

• Adamantinoma - usually older (teens-twenties), may have soft tissue extension.
• Metaphyseal fibrous defect - metaphyseal location.
• Fibrous dysplasia.

Prognosis:

• Self limited

Population:

• Children.
• First 2 decades of life.
• Median 9.5 years.

Microscopic

The lesion has a zonal architecture with a center of immature bone surrounded by more mature lamellar bone. The central spicules of woven bony trabeculae are lined by a layer of osteoblasts. The backgound is a loose and storiform fibrous tissue.

Notes:

• The diagnosis depends on the ratio of fibrous to epithelial tissue which can vary within each particular tumour.
  • Due to the above ample tissue is required for accurate histologic diagnosis.
• Current discussion regarding the definition of an OFD-like adamantinoma.
  • As of 2010, WHO requires absence of keratin-positive cells for OFD.
  • Some accept as OFD lesions with scattered isolated keratin positive spindled cells.
  • Gray zone and varying interpretations of the boundry of OFD, OFD-like adamantinoma and adamantinoma.

DDx:

• Adamantinoma - epithelial elements are prominent and atypical.
• OFD-like adamantinoma - see below.
• Fibrous dysplasia - bony trabeculae lack osteoblastic rimming, not zonal.

Images

• OFD-Tumor Library| [1]
• OFD-Pathology Outlines| [2]
• OFD-Pathology Outlines | [3]
• OFD-Pathology Outlines | [4]
• OFD-Sarcoma Images | [5]
• OFD-Sarcoma Images | [6]
• OFD-Sarcoma Images | [7]
• OFD-Sarcoma Images | [8]

Stains

• Not relevant

IHC

• Keratin positive - isolated cells accepted by some.

Molecular

Clonal chromosomal abnormalities

• Trisomies of chromosomes 7, 8, 12,21, and/or 22

Sign out

BONE, CURRETTAGE:  
- OSTEOFIBROUS DYSPLASIA.

See also

• Tumor Library |[9]
• Sarcoma Images |[10]