The histopathology of camptomelia (bent limbs). A dyschondrogenesis.

Camptomelia is well established syndrome in which the most prominent osseous feature is bowing of the long bones. Although several patients have died, usually due to respiratory insufficiency caused by defects of the cartilage of the tracheal rings and lower respiratory tract, histologic studies of the bone in camptomelia have led to conflicting conclusions about pathogenesis. A complete autopsy of a neonatal case, including serial sections of the long bones, revealed normal enchondral growth sequences of the epiphyseal plate. In the diaphysis, centering around the angle of the bend, the cylinderization process was markedly abnormal. Extensive new secondary trabeculae formed on the concave (posterior) surface of the bone during resorption on the convex (anterior) surface. A cone of dense new bone formed at the apex at the convex anterior angle of the bend. These findings supported previous suggestions that bone formation and remodeling processes were normal. With the variation of bone involvement in different patients, these features indicate that camptomelia is the result of an abnormality of cartilage anlage formation, probably owing to a transient exogenous teratogen. Camptomelia is the preferred term. Basically, the syndrome is a dyschondrogenesis.