Erythrophagocytosis in a patient with B-cell acute lymphoblastic leukemia with t(12;21) (p13.2; q22.1); ETV6-RUNX1: Case report and review of the literature.

Erythrophagocytosis (EP) is extremely rare in de novo acute lymphoblastic leukemia (ALL). We document a rare case, which in addition, showed extensive blast vacuolization. A detailed literature review has also been incorporated with the aim of unraveling the prognostic import of our morphological observations if any. A five-year-old male presented with fever and progressive pallor for 1 month. He had hepatosplenomegaly and bicytopenia. Peripheral smear examination showed 43% blasts. Nuclear and cytoplasmic vacuolations were seen in 75% blasts and EP in 4% blasts. The blasts showed block positivity on periodic acid-Schiff (PAS) stain. Marrow aspirate smears showed 58% blasts displaying a similar morphology. Flow cytometry showed features of a common acute lymphoblastic leukemia antigen (CALLA) positive B-cell ALL with aberrant, dim CD 33 expression in 53.4% of the gated blasts. Fluorescence in situ hybridization showed translocation (12; 21) (p13;q22). The patient responded well to standard induction therapy. To conclude, EP is rarely seen in de novo ALL and is associated with a favorable translocation, t(12;21).