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Musculoskeletal Imaging

E3191. When Bone Attacks: Radiographic Features of Fibrodysplasia Ossificans Progressiva

Bonham J,  Hsiao E,  Garcia-Reyes K,  Jordan E,  Motamedi D. University of California, San Francisco, San Francisco, CA

Address correspondence to J. Bonham (

Background Information: Fibrodysplasia ossificans progressiva (FOP) is an incredibly rare disease characterized by congenital skeletal abnormalities and heterotopic ossification beginning in early childhood and progressing throughout life. These congenital abnormalities along with the progressive formation of mature bone within soft tissues and ligamentous structures result in characteristic radiographic findings. Radiologists play a key role in the diagnosis of FOP, early recognition of which is important as unnecessary invasive procedures that exacerbate new bone formation and can be prevented. FOP is incurable, with therapies targeted at pain management and palliation of symptoms. The purpose of our exhibit is to familiarize the viewer with the characteristic radiographic features of this challenging and unique disease.

Educational Goals/Teaching Points: In this exhibit, we will review the congenital and acquired imaging features of FOP across imaging modalities, including radiography, CT, nuclear medicine bone scintigraphy, and MRI from a variety of cases from our institution. Current therapeutic trials and imaging protocols will also be highlighted.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: Key imaging findings of FOP will be illustrated, including congenital hallux valgus, shortened metacarpals, and facet joint fusion, as well as many illustrative examples of exuberant soft tissue bone formation and the formation of several distinct pseudoarthroses across distant joints. The technical parameters for optimal imaging evaluation will also be reviewed.

Conclusion: FOP is an incredibly rare, unique, and devastating disease, and the radiologist plays a critical role in the initial diagnosis, staging, and follow-up of patients with this condition.