Congenital pseudarthrosis of the clavicle: a histopathological study in five patients.

Congenital pseudarthrosis of the clavicle is usually situated on the right clavicle. Pathological data on pseudarthrosis are scant. The histological analysis of five cases treated by 'en bloc' surgical resection are reported. Enchondral ossification was observed on both sides of the resected pseudarthrosis in two cases. Less characteristic enchondral features were noted in three cases. These findings confirm that the pseudarthrosis is due to the failure of coalescence of the two primary ossification centers of the clavicle.