Contributed by Daniel Marker, MD, PhD
The patient is a premature infant male who was born to a multiparous mother. Early in the mother's pregnancy, routine prenatal screening identified fetal anemia requiring multiple percutaneous umbilical blood sampling (PUBS) procedures and fetal transfusions. A workup for immune mediated causes of fetal anemia was completely negative. During one PUBS procedure, the fetus showed a significant cardiac deceleration, leading to an emergent C-section. His immediate post-delivery course was complicated by multiple prematurity associated comorbidities, as well as unexplained persistent anemia without reticulocytosis requiring transfusion support. Hematology was consulted for the persistent anemia and recommended a bone marrow aspirate and biopsy.
The patient's peripheral blood smear showed only nonspecific anisopoikilocytosis and a mild monocytosis. The bone marrow biopsy was limited due to very scant marrow present for analysis, but appeared to show a normocellular bone marrow with tri-lineage hematopoiesis (Figure 1). An immunohistochemical stain performed on the limited specimen was negative for parvovirus (not shown). The aspirate smears showed marked widespread erythroid dyspoiesis, characterized by bi- and multinucleate late stage erythroid precursors (Figures 2, 3, and 4). The early erythroid precursors appeared normal. An iron stain showed abundant extracellular iron and no ringed sideroblasts (Figure 5). The myeloid and megakaryocyte lineages were unremarkable.
Given the morphologic and clinical findings, targeted molecular analysis was performed. The patient was found to be compound heterozygous for two pathologic mutations in the SEC23B gene.