Tissue iron storage patterns in fetal hydrops associated with congestive heart failure

To learn whether fetal congestive heart failure causes a characteristic tissue iron storage pattern, we selected 15 neonatal autopsy cases of hydrops fetalis in which both the clinical and gross autopsy findings suggested intrauterine congestive heart failure. The latter appeared to be due to functional causes in 10 (3 nonhemolytic anemia, 4 cardiac dysrhythmia, 3 dilated cardiomyopathy) and was associated with cardiac malformation in 5. We graded the amount of hepatocellular siderosis, reticuloendothelial siderosis, and renal tubular siderosis in Perls-stained microscopic sections of liver, spleen, and kidney and compared the iron storage pattern with that in 15 normally developed neonatal autopsy controls (4 preterm, 11 term) and a further 7 with hemolytic anemia (5 alpha-thalassemia, 2 parvovirus B19 infection). Liver cell siderosis was absent in the three cases with nonhemolytic anemia. It was increased in 11 of the remaining 12 cases, as in hemolytic anemia controls. Among the five cardiac malformation cases, three had proximal renal tubular siderosis (as in hemolytic anemia controls) attributed to turbulent blood flow through the heart. Among the five, hydrops appeared to be due to prenatal closure of the foramen ovale in one and to prenatal constriction of the ductus arteriosus in another. In one of the five, and despite complex malformation of the heart, hydrops appeared to be due to complete heart block. We concluded that, although clinical information and morphologic assessment of the heart were basic to identifying a cardiac cause of fetal hydrops, histologic assessment of the pattern of iron storage helped confirm the pathologic diagnosis. Analysis of the pathologic findings led to a scheme for categorizing cardiogenic fetal hydrops.