Acute Erythroleukemia, M6b

The patient was a 47-year-old man whose past medical history was significant for renal transplant, as well as refractory anemia with ringed sideroblasts (Figure 1) diagnosed 1 year previously. He re-presented to his hematologist/oncologist with fatigue and weight loss. The only medications he was taking at the time of presentation were cyclosporine and prednisone. Physical examination was noncontributory. A complete blood count revealed anemia, thrombocytopenia, and rare blasts. A bone marrow aspirate and biopsy were performed and revealed 51% erythrocytic precursors (Figure 2). Characteristic features included the presence of 41% pronormoblasts by French-American-British (FAB) exclusion criteria, with marked dysplastic change and “block-and-blush” periodic acid–Schiff positivity (Figure 3) of the erythroid cell lineage. There were 22% myeloblasts by FAB exclusion criteria, with minimal dysplasia of the granulocytic cell line. A diagnosis of acute erythroleukemia, M6b (pure erythroleukemia, Di Guglielmo disease) was established. Cytogenetic analysis demonstrated a complex karyotype with abnormalities of both chromosomes 5 and 7. Review of the previous bone marrow slides confirmed the original diagnosis. The patient underwent 6 cycles of arabinosylcytosine (cytarabine)/daunorubicin therapy. Sequential intrachemotherapy and postchemotherapy bone marrow specimens revealed ablation of all hematopoietic elements, with the exception of the pronormoblasts. The patient died 2½ months after initial diagnosis.A leukemia composed of purely erythrocytic precursors was first described by Di Guglielmo in 1926 and was designated Di Guglielmo disease. Until recently, this fulminant acute leukemia was alternately classified as a myeloproliferative disorder or a myelodysplastic syndrome. Nevertheless, a number of articles and books have described the complex cytogenetics and extremely poor outcome associated with this disease, which represents a distinct leukemic entity.1–4 The overall presentation and outcome of the patient described here are in keeping with previous descriptions of this condition.1,2 Investigators studying this leukemic process proposed that this disorder be renamed acute erythroleukemia, M6b, and that it be incorporated into the classification of acute leukemias. Recently, the World Health Organization, which is in the process of revising the current FAB classification of myeloid disorders, concurred.5