Objective To explore the hepatic pathology of a patient with erythropoietic protoporphyria (EPP). Methods Percutaneous liver biopsy was performed with a Chiba needle in a 31 year old man suffering from EPP. The sample was fixed in 10% formalin solution, and the paraffin embedded section was stained with H E, PAS, etc. Unstained paraffin embedded and H E stained paraffin embedded sections were examined under polarization microscope. Ultrathin sections were examined in a transmission electron microscope. Results In H E stained sections, deposits of dark reddish brown pigment were seen in the hepatocytes, Kupffer cells, portal macrophages and plugs in the lumen of bile canaliculi and ducts. Under light microscope, such deposits, with rare exception, exhibited striking birefringence with the unique shape of “Maltese cross”. Non membrane limited compact masses of crystals were straight or slightly curved and their dimensions (40 640 nm in length and 6 22 nm in width) were different under the transmission electron microscope. Conclusion Microscopy, especially polarization microscopy, provides a highly sensitive and specific technique for the diagnosis of EPP. Objective To explore the hepatic pathology of a patient with erythropoietic protoporphyria (EPP). Methods Percutaneous liver biopsy was performed with a Chiba needle in a 31 year old man suffering from EPP. The sample was fixed in 10% formalin solution, and the paraffin embedded section was stained with HE, PAS, etc. Unstained paraffin embedded and HE stained paraffin embedded sections were examined under polarization microscope. Ultrathin sections were examined in a transmission electron microscope. Results In HE stained sections, deposits of dark reddish brown pigment were seen in the hepatocytes, Kupffer cells, portal macrophages and plugs in the lumen of bile canaliculi and ducts. Under light microscope, such deposits, with rare exception, showing striking birefringence with the unique shape of “Maltese cross” Non membrane limited compact masses of crystals were straight or slightly curved and their dimensions (40 640 nm in length and 6 22 nm in width) were different under the transmission electron microscope. Conclusion Microscopy, especially polarization microscopy, provides a highly sensitive and specific technique for the diagnosis of EPP.