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Essential thrombocythaemia is a rare pathology in adults and extremely rare in children, making it a diagnostic challenge for paediatricians. The challenge is greater when patients are asymptomatic, despite an incidental discovery of thrombocytosis.. We report the case of extreme thrombocytosis found in an asymptomatic child of 3 years with no personal history or familial history.

Study protocol started by ruling out laboratory errors, infectious disease, haemolytic anaemia, iron deficiency anaemia and autoimmune diseases. Bone marrow sample confirmed elevated megakaryocyte production, with other cell lines within normal ranges. Genetic analysis including JAK2 mutation was also negative, leading to a differential diagnosis of essential thrombocythaemia.

A moderate reduction in platelet count was achieved after 4 weeks of treatment.. Sin antecedentes personales o familiares de importancia. It is often transient, and occurs secondary to various underlying medical, usually inflammatory, disorders. Essential thrombocythaemia ET is a chronic myeloproliferative disorder characterized by megakaryocyte proliferation.

Although the clinical course is benign, is it associated with serious thrombosis and bleeding, in addition to an increased risk for presenting a more serious haematological malignancy.

Over half of all cases are asymptomatic, and thrombocytosis is an incidental finding. Symptoms are nonspecific, with headache being the most widely reported. In , the World Health Organization issued revised diagnostic criteria for myeloproliferative disorder, establishing 4 major, and no minor, criteria for the diagnosis of ET Table 1. Diagnostic criteria for essential thrombocythaemia World Health Organization, 4.

Treatment guidelines are controversial and involve either hydroxyurea or anagrelide. Hydroxyurea is an antimetabolite that selectively inhibits ribonucleoside diphosphate reductase, an enzyme required to convert ribonucleoside diphosphates into deoxyribonucleoside diphosphates, a crucial and probably limiting step in DNA synthesis.

Hydroxyurea is mainly used to treat selected myeloproliferative disorders. Anagrelide is an imidazoquinazoline that inhibits megakaryocyte maturation and reduces elevated platelet counts.

In this study, we report the case of an uncommon clinical presentation in a paediatric patient. The patient was a boy aged 3 years born in , a resident of Mexico City, with no family history of note. The father and mother were both healthy, aged 38 and 34, respectively. The patient lives in an urban dwelling, far from industrial areas, power lines and landfill sites. He denies contact with myelotoxic substances, such as pesticides, benzene, ionizing radiation, or heavy metals.

He is the mother's third child following an uneventful pregnancy, weighing 3. Somatic and functional development. No changes relevant to the current complaint.

Immunizations up to date. The blood count was part of the preoperative workup for circumcision and right side orchidopexy.

The protocol for childhood thrombocytosis, shown in Fig. Diagnostic algorithm to confirm suspicion of essential thrombocythaemia. Well developed male patient, conscious and oriented, active, reactive, with no pallor, pupils equal and reactive to light, oral mucosa moist. No mucosal lesions, no evidence of adenopathy, lung fields are clear and well-ventilated, heart has regular rate and rhythm, no murmurs, abdomen soft, depressible and non-tender, no hepatosplenomegaly, normal peristaltic sounds, no masses, well-developed genitals, full range of motion in extremities, with no oedema or evidence of venous or arterial problems.

The boy was seen again in April with the results of the test Fig. The findings of a new whole blood count showed a platelet count of , The interview and physical examination were both compatible with viral influenza associated with thrombocytosis, and the patient was given symptomatic treatment. At the following appointment, on September 3, , the platelet count was 3,,, and the patient was totally asymptomatic.

Therefore, after ruling out other underlying conditions that could be causing the thrombocytosis, we suspected essential thrombocythaemia, and ordered bone marrow aspiration and specific molecular testing. The findings of these tests met the diagnostic criteria for ET, and the diagnosis was therefore confirmed Table 1. Changes in blood chemistry parameters. Reference ranges and units in brackets. Iron metabolism parameters in the normal range. Serology negative for infection. Molecular biology studies: Normal karyotype 46 XY.

An abdominal ultrasound performed in September was unremarkable, with a normal spleen 9 cm greatest diameter. On September 10, , bone marrow aspiration was performed, showing normocellular bone marrow with abundant, greatly enlarged megakaryocytes forming platelet clumps with abundant cytoplasm and irregular, hyperlobulated nuclei; architecture is otherwise preserved, with a slight increase in eosinophils Fig.

It shows normocellular bone marrow with abundant, greatly enlarged megakaryocytes with abundant cytoplasm and irregular nuclei. Architecture is otherwise preserved, with a slight increase in eosinophils. In paediatric patients, an incidental finding of thrombocytosis should be confirmed with an additional blood count, as some clinical situations can cause a false high platelet count mixed cryoglobulinaemia or lysis.

The primary aim should be to stabilize the patient, and then follow the algorithm shown in Fig. They include tests for infection, iron deficiency anaemia, haemolytic anaemia, and autoimmune disease.

Primarily, they provide a clearer picture of the risk of presenting thrombotic complications from platelet activation. In addition, reports have shown that in patients with very high platelet levels, the likelihood of haemorrhage paradoxically increases as a result of the increased proteolysis of large vWF multimers.

It is important to evaluate the family history of thrombocytosis, as this can suggest hereditary thrombocytosis. The final step involves bone marrow aspiration, which shows the presence of megakaryocyte proliferation, with an increase in the number of mature enlarged megakaryocytes and no significant increase or shift to the left of neutrophil granulopoiesis or of erythropoiesis. The prevalence of essential thrombocythaemia is around 60 times greater in adults than in children.

The JAK2VF mutation is also less common in children, making pathogenesis and diagnostic techniques in children a considerable challenge. The mutation, however, has primarily been reported in other myeloproliferative neoplasms, such as polycythaemia vera. Although some cytoreductive therapies in children have been reported, the lack of evidence has prevented any clear consensus on the correct approach. This is why the main sources for such treatment consist of case reviews reporting the successful use of hydroxyurea, with anagrelide and interferon being considered second line treatment in high risk patients that either do not tolerate or do not respond to hydroxyurea.

Some authors have recently pointed to interferon alpha as the treatment of choice, based on its excellent safety profile even in pregnant women, and because it does not increase the already considerable risk of leukaemia. This therapy has the added advantage of oral administration, in contrast to interferon alpha, which must be administered by trained staff. Essential thrombocythaemia is an uncommon disorder in children. For diagnostic purposes, it is of vital importance to differentiate between essential thrombocythaemia and secondary thrombocytosis; a negative JAK2 mutation test does not necessarily rule out the diagnosis, and treatment should be started in symptomatic patients, or in those at high risk for complications.

The authors declare that they have no conflict of interests. ISSN: See more Follow us:. Previous article Next article. Issue 3. Pages July - September Download PDF. Espinosa-Elizondo a ,. Corresponding author.

Balmis , Col. Doctores, Del. This item has received. Under a Creative Commons license. Article information. Show more Show less. Table 1. Diagnostic criteria for essential thrombocythaemia World Health Organization, The challenge is greater when patients are asymptomatic, despite an incidental discovery of thrombocytosis.

A moderate reduction in platelet count was achieved after 4 weeks of treatment. Essential thrombocythaemia. Palabras clave:. Trombocitemia esencial. Bone marrow histology: megakaryocyte proliferation with large and mature morphology with little or no granulocyte or erythroid proliferation. Not meeting WHO criteria for chronic myeloid leukaemia, polycythaemia vera, primary myelofibrosis, myelodysplastic syndrome or other myeloid neoplasm. Figure 1. Figure 2. Figure 3.

Tordecilla, A. Soto, et al. Rev Chil Pediatr, 71 , pp. Kucine, K. Chastain, M.


Trombocitose essencial

How common are myeloproliferative neoplasms? Am J Hematol. Population-based incidence and survival figures in essential thrombocythemia and agnogenic myeloid metaplasia: an Olmsted County Study, Trends in the incidence of polycythemia vera among Olmsted County, Minnesota residents, Long-term survival and blast transformation in molecularly annotated essential thrombocythemia, polycythemia vera, and myelofibrosis. Survival and prognosis among patients with contemporary polycythemia vera: an international study. Survival and disease progression in essential thrombocythemia are significantly influenced by accurate morphologic diagnosis: an international study.


Trombocitemia esencial y policitemia vera

A abordagem de tratamento deve ser individualizada com base nos fatores de risco. Os pacientes precisam realizar hemogramas completos regularmente. The revision to the World Health Organization WHO classification of myeloid neoplasms and acute leukemia external link opens in a new window. Modification of British Committee for Standards in Haematology diagnostic criteria for essential thrombocythaemia external link opens in a new window. For any urgent enquiries please contact our customer services team who are ready to help with any problems.


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