Thursday, 30 April 2020


Written by Pedro J. Espinosa Prados | Raquel Madera Pajín | Alejandro Vega Junco

Figure 1. An image of a peripheral blood smear is presented, stained with fast panoptic, of a 92 years old patient with essential thrombocythemia (ET), JAK2 positive, diagnosed in 2008 with a score in the Dynamic International Prognosis Score System (DIPSS) of 5 (high risk).

The patient goes to the emergency with a clinical profile of tiredness, dizziness, fatigue, and abdominal pain. In the analytical highlights the presence of normochromic normocytic anemia, with thrombopenia, neutrophilic leukocytosis and a significant increase in LDH values (Hemoglobin: 8,5 g/dL, MCV: 88,8 fL, MCH: 26,3 pg, platelets: 34.000/mm3, leukocytes: 103.300/mm3, neutrophils: 71.160/mm3, LDH: 855 UI/L). Studying the blood smear showed dysplastic neutrophils with segmentation and hypodesgranulation abnormalities; 61% of medium-sized blasts, with a nucleus that may have an unclear nucleolus and sometimes a kidney-shape configuration, moderate-sparse cytoplasm, without Auer canes and myeloperoxidase positive in 2-3% of blasts. In addition, marked anisopoiquilocitosis and anisochromia were observed.
These findings guide the diagnosis of the patient of acute non-lymphoblastic leukemia secondary to ET. Azacitidine treatment was started. After three cycles, it was resolved to suspend the treatment after confirming the progression of the disease, being refractory to it. The patient refuses to continue with chemotherapeutic treatment, and it is decided to initiate palliative treatment.

ET is a chronic myeloproliferative neoplasm that primarily involves the megakaryocytic lineage. The diagnosis of ET requires compliance with the following criteria1-4:

  • Platelet count ≥450x109/L in peripheral blood.
  • Bone marrow biopsy showing a predominance of mature megakaryocytes, large and with hyperlobulated nuclei.
  • Not to meet the WHO criteria for other myeloproliferative neoplasms (chronic myeloid leukemia, primary myelofibrosis, polycythemia vera, myelodysplastic syndrome or other myeloid neoplasia).
  • Janus kinase 2 (JAK2), calreticulin (CALR) or myeloproliferative leukemia virus oncogene (MPL) mutation.

The median age at diagnosis is 68 years, with a M:F ratio of 0,8:1, being most prominent in women <60 years of age5.
Treatment is primarily directed toward decreasing the risk of thrombosis and lowering the platelet count. Besides, treatment is tailored to each patient`s risk profile, where patients are classified as high risk or low risk based on age and history of thrombosis6.

The rate of progression of ET to acute myeloid leukemia (AML) is less than 1% at 5 and 10 years and approximately 2% at 20 years. In the risk factors for progression of ET to AML are included history of thrombosis and extreme thrombocytosis1.

Death rate are approximately 3% at 5 years, 5% at 10 years, and 25% at 15 years. Within the risk factors, include older age, leukocytosis greater than 11x109/L, hemoglobin less than 12 g/dL, and history of thrombosis1.


  1. Chung-Che C, Ohgami RS. Precision molecular pathology of myeloid neoplasms. 2018. 428 p.
  2. Besses C, Cervantes F. Neoplasias mieloproliferativas crónicas Filadelfia negativas. GEMFIN. 2016. 99p.
  3. Swerdlow SH, Campo E, Lee Harris N, Jaffe ES, Pileri SA, Stein H, et al. WHO Classification of tumours of haematopoietic and lymphoid tissues. International Agency for Research on Cancer; 2017. 588 p.
  4. Wiernik PH, Goldman JM, Dutcher JP, Kyle RA. Neoplastic Diseases of the Blood. 2013. 1410 p.
  5. Srour SA, Devesa SS, Morton LM, Check D, Curtis RE, Linet MS, et al. Incidence and patient survival of myeloproliferative neoplasms and myelodysplastic/myeloproliferative neoplasms in the United States, 2001-2012. Br J Haematol. 2017;174(3):382–96.
  6. Tefferi A, Barbui T. Polycythemia vera and essential thrombocythemia: 2015 update on diagnosis, risk-stratification and management. Am J Hematol. 2015;90(2):163-73.


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