Erythropoietic protoporphyria. A light, electron, and polarization microscopical study of the liver in three patients

Two of three patients with erythropoietic protoporphyria showed pigment deposits with typical red porphyrin fluorescence on liver biopsy specimens. Birefringence of this pigment by polarized light is due to its crystalline nature, as demonstrated by electron microscopy. There was slight portal inflammation in these cases. A liver biopsy specimen from a third patient was normal.