A Case of de nova Early Erythroblastic Leukemia Supporting A Proposal of AML M6 ′variant′

Acute myeloid leukemia (AML) with erythroid features have been designated as AML M6 according to the FAB clasification, where the difinition of AML M6 is based on the association of an erythroblastosis comprising more than 50% of the nucleated bone marrow cells and an excess of myeloid blast cells.1 However, this definition is restrictive, thereby excluding rare cases of erythroleukemia (EL) where the blast cells show features of a maturation arrest at an tidy stage of erythroid differentiation with no increase of myeloid blast cells. Such cases have been firstly described as ′cryptic ′ or ′early ′ erythroid leukemia by Greaves et al.2 and sequentially as ′early Erythroblastic leukemia ′ by Villeval et al.3 Furtheremore, in a recent report, Garand et al. have proposed to classify these rare minimally differentiated variants of AML M6 as M6 ′variant′4 At that time, we had not encountered such de now AML cases. However. more recently, we have seen a case of EL showing minimally differentiated erythroid-lineage of blast cells with no increase of myeloid blast cells, thereby supporting the first proposal of Garand et al.