If parvovirus B19 is the cause, scattered giant pronormoblasts can be seen through the bone marrow.
The prominent finding was erythroid hyperplasia, demonstrated by an increased number of red cell precursors: pronormoblasts and few polychromatophilic normoblasts and orthochromic erythroblasts.
The biopsy contained large, immature cells corresponding to the pronormoblasts seen on the bone marrow smear.
Most patients with parvovirus infection have hypocellular marrow and classic giant pronormoblasts with intranuclear inclusions.
Pronormoblasts are intermediate in size to large, with round nuclei, fine chromatin, often prominent nucleoli, and deeply basophilic and agranular cytoplasm.
Prognostic significance of pronormoblasts in erythrocyte predominant myelodysplastic patients.