Fecal porphyrin abnormalities in a patient with features of Rotor's syndrome.
Detailed porphyrin analysis and additional ultrastructural abnormalities of liver cells are described in a patient with features of Rotor's syndrome. Normal values of porphyrin precursors, delta-aminolevulinic acid and porphobilinogen, and porphyrins were found in plasma, urine, and erythrocytes. However, fecal porphyrin excretion was markedly increased to 406 micrograms/g dry stool weight (normal range less than 100 micrograms/g) constituted predominantly of protoporphyrin 225 micrograms/g (normal range less than 76 micrograms/g),. with a smaller increase in coproporphyrin III of 56 micrograms/g (normal range less than 20 micrograms/g). Increased fecal porphyrin excretion in this patient appears to reflect abnormal hepatic porphyrin excretion. Electron microscopic examination of liver biopsy tissue showed new abnormalities of peroxisomes and mitochondria. The predominant abnormality of mitochondria was "bleb" deformation of the outer membrane and these changes may reflect abnormal hepatic mitochondrial porphyrin metabolism. The significance of abnormalities involving peroxisomes is uncertain. Increased fecal porphyrin excretion may be a feature of Rotor's syndrome that requires further study.