Fibrochondrogenesis: radiologic and histologic studies.

Fibrochondrogenesis is a distinct, neonatally lethal, short-limb skeletal dysplasia which was first described in a single patient in 1978. We report the radiographic and morphologic studies of 2 additional unrelated stillborn infants with fibrochondrogenesis. This syndrome has distinct radiographic and chondro-osseous morphologic defects different from those seen in the other known skeletal dysplasias. The long bones are short and dumbbell-shaped with metaphyseal flare. The spine is platyspondylic with superior-inferior clefting defects, and the ribs are short and distally cupped. The growth-plate cartilage is grossly disorganized and has a densely fibrous collagenous matrix when examined by light and electron microscopy. Light, transmission, and scanning electron microscopy shows diaphyseal and metaphyseal trabecular bone to be normal.