Fibrodysplasia ossificans progressiva associated with osteochondromatosis: A case report.

Fibrodysplasia ossificans progressiva is a rare and severely debilitating genetic disorder affecting approximately 1 in 2 million people. It is characterized by progressive heterotopic ossification of soft tissues, leading to the formation of ectopic bone in extraskeletal areas, as well as congenital malformations of the great toes. FOP can also be considered a disorder of osteochondrogenesis, with most musculoskeletal abnormalities related to dysregulated chondrogenesis, such as heterotopic endochondral ossification, abnormal cartilage formation, growth plate dysplasia, osteochondroma formation, and early arthropathy. The frequent lack of awareness of this disease often results in diagnostic errors, delays in diagnosis, and unnecessary interventions, sometimes with irreversible consequences. We report the case of a 2-year-old girl with no significant medical or family history, presenting with bilateral hallux valgus and firm subcutaneous nodules on the back and lower limbs. A thoracoabdominal and lower limb computed tomography scan revealed muscular ossifications and osteochondromatosis, confirming the diagnosis of fibrodysplasia ossificans progressiva.