1. Clinical history: A 78 year old male patient presented with long standing leukocytosis, persistent monocytosis and splenomegaly (diameter 15 cm). Diagnosis of chronic myelomonocytic leukaemia was made and the patient was treated with hydroxyurea. One year late, the patient was admitted to the hospital because of fever and pancytopenia (Hb level 70 g/l, WBC count 3x10^9/l, Plt count 25x10^9/l. An acute megakaryoblastic leukaemia was diagnosed. 1.1 Peripheral blood counts: Hb level 107 g/l, WBC count 10x10^9/l, (neutrophils 5x10^9/l; lymphocytes 1.7x10^9/l, monocytes 2.3x10^9/l), Plt count 1.000x10^9/l. 1.2 Biopsy fixation and decalcification details: Bouin's fixation, EDTA decalcification, paraffin embedding 2. Details of microscopic pathology biopsy: BM biopsy showed a 90% cellularity, slight dyserythropoiesis, moderate myeloid hyperplasia and marked megakaryocytic proliferation with slight dysplasia. Most megakaryocytes were large, with hyperlobulated nuclei, and arranged in several clusters; few were small with hypolobulated nuclei. CD68PGM1/CD14 positive monocytic cells represented 15% of overall BM cellularity, promonocytes were 2% and CD34 positive blasts 2%. Slight reticulin fibrosis (WHO MF-1) was seen. 2.3 Cytogenetics: 46,XY; deletion/monosomy 5,7 and 17: negative; deletion 20q12: negative; trisomy 8: negative; BCR/ABL translocation and 9q34(ASS) deletion: negative; 12p13(ETV6) translocation/deletion: negative. 2.4 Molecular analysis: BCR/ABL rearrangement (p210, p190): negative. RQ-PCR JAK2 V617F mutation load: 15.3%. 3. Interesting feature(s) of submitted case: In the present case, the original BM biopsy showed hypercellularity, with granulocytic and monocytic proliferation associated with a marked proliferation of the megakaryocyte lineage and JAK2V617F positivity: the findings were consistent with CMML (myeloproliferative type). One year later, BM biopsy showed a 80% infiltration of large size blasts, with strong CD61 (membrane and cytoplasm) and FVIII RA immunopositivity, and a diffuse moderate fibrosis (WHO MF-2), consistent with acute megakaryoblastic leukaemia. 4. Proposed diagnosis: Chronic myelomonocytic leukaemia (proliferative type). 5. Comments: The transformation of our case of CMML into an acute myeloid leukaemia (megakaryoblastic type) may be associated to the prominent proliferation of the megakaryocytic lineage observed in the initial biopsy, induced by JAK2V617F mutation.
Chronic myelomonocytic leukaemia with marked thrombocytosis and JAK2V617F mutation transformed into an acute megakaryoblastic leukaemia.
PICH, Achille;RIERA, Ludovica;
2013-01-01
Abstract
1. Clinical history: A 78 year old male patient presented with long standing leukocytosis, persistent monocytosis and splenomegaly (diameter 15 cm). Diagnosis of chronic myelomonocytic leukaemia was made and the patient was treated with hydroxyurea. One year late, the patient was admitted to the hospital because of fever and pancytopenia (Hb level 70 g/l, WBC count 3x10^9/l, Plt count 25x10^9/l. An acute megakaryoblastic leukaemia was diagnosed. 1.1 Peripheral blood counts: Hb level 107 g/l, WBC count 10x10^9/l, (neutrophils 5x10^9/l; lymphocytes 1.7x10^9/l, monocytes 2.3x10^9/l), Plt count 1.000x10^9/l. 1.2 Biopsy fixation and decalcification details: Bouin's fixation, EDTA decalcification, paraffin embedding 2. Details of microscopic pathology biopsy: BM biopsy showed a 90% cellularity, slight dyserythropoiesis, moderate myeloid hyperplasia and marked megakaryocytic proliferation with slight dysplasia. Most megakaryocytes were large, with hyperlobulated nuclei, and arranged in several clusters; few were small with hypolobulated nuclei. CD68PGM1/CD14 positive monocytic cells represented 15% of overall BM cellularity, promonocytes were 2% and CD34 positive blasts 2%. Slight reticulin fibrosis (WHO MF-1) was seen. 2.3 Cytogenetics: 46,XY; deletion/monosomy 5,7 and 17: negative; deletion 20q12: negative; trisomy 8: negative; BCR/ABL translocation and 9q34(ASS) deletion: negative; 12p13(ETV6) translocation/deletion: negative. 2.4 Molecular analysis: BCR/ABL rearrangement (p210, p190): negative. RQ-PCR JAK2 V617F mutation load: 15.3%. 3. Interesting feature(s) of submitted case: In the present case, the original BM biopsy showed hypercellularity, with granulocytic and monocytic proliferation associated with a marked proliferation of the megakaryocyte lineage and JAK2V617F positivity: the findings were consistent with CMML (myeloproliferative type). One year later, BM biopsy showed a 80% infiltration of large size blasts, with strong CD61 (membrane and cytoplasm) and FVIII RA immunopositivity, and a diffuse moderate fibrosis (WHO MF-2), consistent with acute megakaryoblastic leukaemia. 4. Proposed diagnosis: Chronic myelomonocytic leukaemia (proliferative type). 5. Comments: The transformation of our case of CMML into an acute myeloid leukaemia (megakaryoblastic type) may be associated to the prominent proliferation of the megakaryocytic lineage observed in the initial biopsy, induced by JAK2V617F mutation.
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