Congenital ectopic nail with bone deformity.

This report describes two cases of congenital ectopic nail with bone deformity. Histologically, the squamous epithelium of the nail matrix lacked a definite granular layer. Resected nail tissue was connected with the periosteum of the tip of the ungual phalanx, which suggested that the contact of the ectopic nail matrix with the periosteum could impede intramembranous ossification and deform the bone shape.