Fibrodysplasia ossificans progressiva (FOP) is an extremely rare skeletal dysplasia with characteristic imaging and clinical findings, which includes bilateral hallux valgus, monophalangic great toes with short and stout first metatarsals, heterotopic ossification of muscles and connective tissues, short broad femoral necks, pseudo exostoses, short and stout first metacarpals, C2-C7 facet joint fusion, large posterior elements, and tall narrow vertebral bodies.
We present a case of an 8-year-old male child who came with complaints of multiple progressive hard swellings over the neck, chest, and abdomen with restriction of movements for a duration of 2 years and deformity of great toe on both sides since birth. On clinical examination, the patient had multiple non-tender hard bony swellings in neck, chest, and abdominal wall with bilateral hallux valgus deformity. Radiographic examination revealed well- defined rib-like ectopic osseous outgrowths in the posterior aspect of neck, soft tissues of chest and abdominal wall, bilateral hallux valgus, monophalangic great toe and short first metatarsals with normal cervical vertebral bodies, posterior elements, short first metacarpals bilaterally, and pseudo exostoses in medial aspect of upper one-third of both tibia. With the above classic findings, the diagnosis of FOP was made. Early diagnosis of the condition is very important in these cases as intramuscular injections, biopsies, and trivial trauma can exacerbate the condition with painful flare-ups.
Limb specific Acvr1‐knockout during embryogenesis in mice exhibits great toe malformation as seen in Fibrodysplasia Ossificans Progressiva (FOP)
