Dermatohistopathologic changes in bovine congenital porphyria.

Congenital porphyria was diagnosed in 4 crossbred cattle. All had pink-brown discoloration of the teeth and amber colored urine, which fluoresced bright orange with exposure to ultraviolet light. Elevated levels of uroporphyrin and coproporphyrin were found in the urine of all 4 cattle. Skin biopsies taken from 2 of the cattle revealed subepidermal blister formation and thickening of upper dermal blood vessel walls with deposition of a PAS-positive, hyaline-like material.