A DISTINCT SUBTYPE OF M4 M5 ACUTE MYELOBLASTIC-LEUKEMIA (AML) ASSOCIATED WITH T(8-16)(P11-P13), IN A PATIENT WITH THE VARIANT T(8-19)(P11-Q13) - CASE-REPORT AND REVIEW OF THE LITERATURE/

Acute myeloblastic leukemia (AML) with t(8:16) or its variant t(8:V) h as been rarely reported. A high proportion of patients are infants and children, often with a bleeding tendency and disseminated intravascul ar coagulopathy (DIC). Only one-third of the de novo patients remain i n the first complete remission following multiagent chemotherapy and b one marrow transplantation (BMT). Morphocytochemically, the disorder i s classified as an M5, M4, or M4/M5 variant. In the presented case, wi th the variant t(8:19)(p11:q13), comprehensive light and electron micr oscopic blast cell characterization showed monocytic and granulocytic features compatible with the M4 subtype (on the monocytic predominance range of the French-American-British classification scale). Although hemophagocytosis, one of the hallmarks of the disease, was rare in our patient, numerous autophagic vacuoles were present. Immuno- and genot yping showed a myelomonocytic phenotype with no evidence of early prog enitor antigen expression or mixed leukemia. These results and those o f previous reports support the high specificity of t(8:16) or its vari ants to the unique M4/M5 type leukemia and the role of a gene on 8p11 in this specific transformation.