#00062725

A three-year old girl presented with an acute history of fever and hematemesis. Clinical examination revealed pallor, petechiae, subconjunctival haemorrhage and firm hepatomegaly. A complete blood count showed, Hb: 4.6-g/L, white blood cell count (WBC): 228.7×109/L and a platelet count: 18×109/L. The coagulation profile suggested disseminated intravascular coagulation. A Wright-Giemsa stained peripheral blood smear demonstrated leukemic promyelocytes and red blood cell clumping (panel A, black-arrow original magnification×10). The promyelocytes (panel A inset) were hypo-granular with bilobed nuclei (panel B, original-magnification×40), demonstrating frequent Auer rods (panel C, red arrow, original-magnification×100). A peripheral blood flow cytometry demonstrated positivity for CD13, CD33, Anti-MPO and CD45; and negativity for HLA-DR and CD34. Reverse-transcriptase polymerase chain reaction was positive for PML-RARα. Direct-Coombs test was positive. All-trans retinoic acid was initiated accompanied by transfusion of appropriate blood products. However, she succumbed to pulmonary haemorrhage within 48-hours.

            Microgranular variety of APML is an uncommon variant characterized clinically by elevated WBC counts; and morphologically by promyelocytes with bilobed/multilobated nuclei, relative paucity of Auer rods and scattered cytoplasmic granules. The concomitant presence of red blood cell agglutination is unusual and seldom reported. Immune dysregulation associated with clonal expansion of leukemia may possibly lead to autoimmune hemolysis.