Fibrodysplasia ossificans progressiva
 Discussion of Fibrodysplasia ossificans progressiva
- Fibrodysplasia ossificans progressiva is a rare, slowly progressive disorder characterized by fibroblastic proliferation, subsequent calcification, and ossification of subcutaneous fat, skeletal muscle, tendons, aponeuroses, and ligaments.
- Frequently associated with symmetric malformation of the digits, especially the thumbs and great toes.
- Fibrodysplasia ossificans progressiva typically occurs in children (almost half of the patients presenting by age 2 years).
- The disease is also known as myositis ossificans progressiva, which is a misnomer in that the disease affects primarily connective tissue, with the changes in muscle being secondary.
- The disease is usually sporadic but may be inherited as an autosomal dominant trait with variable penetrance.
- Patients usually present with localized soft-tissue swelling.
- In time, the swelling resolves and the soft-tissue masses coalesce, fibrose, and calcify, leading to the formation of “bony bridges”.
- Bony bridges cause restriction of respiration and ambulation and skeletal contractures.
- The ossification process may occur quickly, with doughy nodules progressing to well-defined ossified lesions within weeks.
- The disease course is characterized by remissions and exacerbations.
- Local trauma, including surgery, has been implicated in disease progression.
 Imaging Findings for Fibrodysplasia ossificans progressiva
- The major radiographic features of fibrodysplasia ossificans progressiva include ectopic ossification, short bone abnormalities, and vertebral abnormahities.
- Almost all patients have microdactyly of the thumbs.
- The vertebral bodies in the cervical and lumbar regions have a narrowed anteroposterior diameter, and there may be fusion of the posterior arches in the cervical spine.
- In addition, there may be epiphyseal changes, calcaneal spurs, patella alta, hallux valgus, and cortical thickening of the tibia.
- Ectopic ossification usually begins in the neck and paravertebral region and progresses to ossified bars and bony bridges throughout the soft tissue.
 See Also
 External Links
 References for Fibrodysplasia ossificans progressiva
- MJ Kransdorf, and JM Meis. From the archives of the AFIP. Extraskeletal osseous and cartilaginous tumors of the extremities. RadioGraphics 1993 13: 853-884.