Erythroid nuclear irregularities: a review of fetal and neonatal autopsies and correlation with clinical features

In our autopsy experience, abnormal erythroblast nuclear contours are frequently observed in the stillborn fetus or neonate without marrow failure disorders. Bone marrow and liver slides from autopsies of fetuses and infants less than six months of age were analyzed for the percent erythroblasts with nuclear irregularities, and correlated with gestational age at birth, days of life, cause of death, postmortem interval, presence of hydrops, and hematocrit at death. In total, 77 cases had sufficient marrow or liver erythroblasts for review, including 37 stillborns and 40 liveborns. Erythroid nuclear irregularities in >10% of erythroid precursors were present in either the liver or marrow in 54% of stillborns and 68% of liveborns, more commonly seen in the liver. Cases with <1% abnormal erythroblasts were rare. Fetuses with >10% abnormal erythroblasts in the liver were more likely to have died in utero, whereas those with less were more commonly terminations (p=0.008). No significant association between the extent of abnormal erythroblasts and the presence of anemia or hydrops was observed. While the finding of erythroblasts with nuclear irregularities is common in stillborns and liveborns and could be solely a postmortem artifact, we cannot exclude a potential fetal erythropoietic response to hypoxic stimuli. Dyspoietic-appearing erythroblasts alone should not be used as the basis for the diagnosis of a marrow failure disorder at autopsy.