Lupus erythematosus cells in a bone marrow aspirate

A teenage girl presented with fevers of unknown origin and pancytopenia. Complete blood count showed anemia (hemoglobin, 9.0 g/dL), neutropenia (1.7 × 10⁹/L), and thrombocytopenia (66 × 10⁹/L). The bone marrow was hypocellular with left shifted hematopoiesis and myeloid hypoplasia. Aspirate smears were notable for a prominent population of neutrophils with crescentic nuclei that engulfed blue amorphous material (Fig. 1 panels A and B, Wright-Giemsa, magnification × 1000). The trephine biopsy showed similar cells with crescentic nuclei and eosinophilic material (Fig. 1 panels C and D, hematoxylin and eosin × 400). Flow cytometry was negative for an abnormal population. EBV by in situ hybridization and parvovirus immunohistochemistry were negative. Subsequent serologic testing was positive for ANA (1:1280), low C3/C4, anti-dsDNA, anti-SM and anti-B2GP1. A kidney biopsy demonstrated findings consistent with class III lupus nephritis.