Clinical and ultrastructural study of three cases of acquired nevoid telangioectasia: (1) angioma serpiginosum, (2) angiokeratoma neviformis, and (3) unilateral nevoid telangiectasia. Despite the clinical similarities, the ultrastructural aspects of these lesions are different, showing: (1) ectasia of arteriolar type, (2) budding of capillaries, and (3) ectasia of venular type. The physiopathological mechanism of these lesions seems to be different.