Institutional Affiliation  
Saint Vincent Hospital Learning 

Objectives 
1. Define Subtypes of Fibrous Dysplasia 
2. Review CT and MRI features of Fibrous Dysplasia 
3. Differentiate CT and MRI features  
4. Outline Management Recommendations Background Fibrous Dysplasia (FD) is an uncommon non malignant developmental anomaly characterized by replacement of medullary bone by fibrous tissue. Patients with Fibrous dysplasia are generally asymptomatic with lesions demonstrating slow indolent growth. Rapid growth is rare and may displace adjacent structures such as the optic nerve, eye/globe, nasal airway, cranial nerves, middle ear ossicles, and teeth. Involvement of long bones may predispose to pathologic fractures. Malignant transformation is rare however it is seen in 1% of lesions. Surgical resection is advocated in cases of rapid growth in order to prevent complications of blindness or hearing loss. 

Conclusion 
Fibrous Dysplasia has three subtypes; Monostotic, Polyostotic, and as part of McCune Albright syndrome. Patients are generally asymptomatic, however, lesions may be treated surgically in cases of rapid growth if there is significant mass effect on local structures. Although uncommon, Fibrous Dysplasia is a potential tumor mimicker and recognition of characteristic findings on CT and MRI is vital for the radiologist to correctly guide therapy and avoid misdiagnosis.

Fibrous Dysplasia: Imaging Features and Management