Age / Sex : 38 / F

Age / Sex : 38/ F

Chief complaint :    Headache

fibrous dysplasia

Discussion

Findings:  

Simple radiograph of the skull reveals expansile ground-glass opacity at left side high parietal bone.

Axial and coronal T1-weighted MR show bilateral thickening of the skull vault with mixed signal intensity at left parietal bone. T2-weighted coronal MRI showing that the mass is predominantly low signal. There are also cystic components.  

Differential Diagnosis: Hemangioma

Langerhans cell histiocytosis (eosinophilic granuloma)

Aneurysmal bone cyst

Multiple myeloma

Metastasis

Diagnosis:  Fibrous dysplasia

Discussion:

The differential diagnosis of craniofacial fibrous dysplasia varies depending on the location, extent of involvement and the appearance of the lesion.

The differentials for a lytic skull vault lesion would include Langerhans cell histiocytosis (eosinophilic granuloma), hemangioma, aneurysmal bone cyst, multiple myeloma and metastasis. More generalized involvement of the skull base tends to be more sclerotic. This form of fibrous dysplasia may need to be differentiated from Paget disease or osteopetrosis. A more localized sclerotic skull lesion, especially of the sphenoid bone may be difficult to differentiate from hyperostosis associated with a meningioma.

References:

1.     Lisle DA, Monsour PAJ, Maskiell CD. Imaging of craniofacial fibrous dysplasia  Journal of medical Imaging and radiation Oncology 2008;52:325-332

2.     Jee WH, Choi KH, Chae BY, Shinn KS. Fibrous dysplasia: MR imaging characteristics with radiopathologic correlation AJR 1996;167:1523-1527