Hematogones Detected by Flow Cytometry in a Child with Vitamin B12 Deficiency.

Vitamin B12 deficiency is a known cause of megaloblastic anemia and bone marrow failure. Bone marrow biopsies are not frequently performed as part of the diagnostic workup and can demonstrate morphologic features that overlap with myelodysplastic syndrome (MDS) and acute leukemia. We describe a case of a dysplastic bone marrow with increased bone marrow hematogones detected by flow cytometry in a child with vitamin B12 deficiency. Hematogones are normal B cell precursors, and hyperplasia has been described in a variety of often reactive conditions and also disease. Hematogones are not typically seen in MDS. The presence of hematogones may help differentiate the dysplastic changes seen in vitamin B12 deficiency from MDS.