Institution: H. Lee Moffitt Cancer Center
Additional authors:Hailing Zhang
Session: AML secondary to myeloproliferative neoplasms and other types of disease progression in MPN
HISTORY
73-year-old male had erythrocytosis was diagnosed with polycythemia vera in 1992. He was initially treated with phlebotomies and hydrea, which were unable to control his erythrocytosis adequately. He was then treated with alpha-interferon with modest improvement. In 2012 he started to have pancytopenia.
DETAILS
Iliac crest bone marrow aspiration and biopsies were performed. Biopsies performed at outside hospitals (5/21/2012 and 11/20/2012) showed myelofibrosis and increased blasts up to 30-40% of the cellularity. Bone marrow biopsy at Moffitt Cancer Center on 1/8/2013 showed fibrotic marrow with 100% cellularity (Fig. 1). There are 8% blasts in peripheral blood (Fig. 2) but aspirate smear was hemodilute without adequate spicules available. There was a diffuse increase in immature cells in the marrow (Fig. 3).
IMMUNOHISTOCHEMISTRY AND FLOW CYTOMETRY
Immunohistochemical staining for CD34 and CD117 revealed approximately 50-60% blasts (Fig. 4). The blasts were also positive for CD61, CD31, and Factor VIII (Fig. 5, 6). A subset of the blasts was positive for myeloperoxidase.
CYTOGENETIC FINDINGS
Cytogenetics showed a complex male karyotype (49,XY,+1,der(1)t(1;7)(q10;p10),add(17)(p13),+3mar[3]/46,XY[17].
MOLECULAR FINDINGS
Molecular study was positive for JAK2 V617F mutation.
INTERESTING FEATURES
Polycythemia vera (PV) is known to occasionally transform into acute leukemia. This is a rare case of megakaryoblastic transformation of PV with myelofibrosis. The megaloblastic phenotype of the blasts were revealed by strong positivity with CD61, Factor VIII and CD31 of the blasts on immunohistochemical stains. The prognosis of cases of PV that have transformed into acute leukemia is generally poor because the majority of such cases are refractory to chemotherapy.
PROPOSED DIAGNOSIS
Post polycythemia vera myelofibrosis and megakaryoblastic transformation.
CONSENSUS DIAGNOSIS
Blast phase of polycythemia vera in post-polycythemic myelofibrotic stage: acute megakaryoblastic leukemia