Metaphyseal abnormalities in fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP) is a rare, congenital disorder characterized by diffuse ossification of extraskeletal connective tissue. The classical features and progression of the disease are described and three cases are presented which fall into the general pattern of FOP clinically and radiologically. A constant feature seen was a slight metaphyseal flaring with spiking at the edges of the metaphyses, compatible with minor alteration in bone morphology during growth. These changes cannot be seen after epiphyseal fusion. The major abnormalities persist into adult life.