ACUTE MEGAKARYOCYTIC LEUKEMIA: A REPORT OF TWO CASES

*Dr. Bharti Saklani, Dr. Mansi Kala and Dr. Avriti Baveja

ABSTRACT

AML M7 is a rare subtype of AML and accounts for approximately 1 to 2 % of all AML and about 10% of paediatrics AML.[1] However, AMKL is the most frequent AML in children with downsyndrome.[2,3] It is characterized by proliferation of >20%blasts, of which 50% should be of megakaryocytic lineage. Morphologically, blasts are medium to large sized with round to indented nuclei and one or more nuclei. Immunophenotyping reveals megakaryoblast expression of one or more platelet glycoproteins: CD41 (glycoproteinIIb/IIIa) and/or CD61 (glycoprotein IIIa). Myeloid markers CD13 and CD33 may be positive; CD36 is typically positive.[4] Blasts are negative with the anti-MPO antibody and other markers of myeloid differentiation. We report 2 cases of AMKL that presented in our hospital. Case 1 A 22 year old female who presented to EMR with fever and pain abdomen. On examination, the patient was febrile, there was bilateral submandibular lymphadenopathy. Peripheral blood examination showed 25% blasts were positive for CD45 (intermediate), CD41, CD4, CD13,CD33 and CD117(heterogeneously). Blasts were negative for CD19, cytoplasmic CD3, MPO, Cd235a and other myeloid markers and hence a diagnosis of AML M7. She was started on 3+7 with Daunorubicin and cytarabine. Case 2, the second case is a 2 year old male child who is a known case of down syndrome. He presented to the hematology OPD with complaints of fever since 2-3 months. Complete hemogram revealed pancytopenia. Bone marrow biopsy revealed marked fibrosis. There was marked megakaryocytic hyperplasia with blasts which showed high N/C ratio, round to oval nuclei, open chromatin and prominent nucleoli. IHC was done which showed positivity for CD61,CD34,CD56,CD 7,CD117,CD71. The blasts were negative for MPO. A diagnosis of acute myeloid leukemia – megakaryoblastic type associated with downs syndrome was made. Induction chemotherapy comprising of Daunomycin and cytarabine was given to the patient. Post induction bone marrow examination suggested no residual disease So, consolidation therapy as described in ML DS2006 protocol was given.

Keywords: AMKL, AML M7, Immunophenotyping.