<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1665-1146</journal-id>
<journal-title><![CDATA[Boletín médico del Hospital Infantil de México]]></journal-title>
<abbrev-journal-title><![CDATA[Bol. Med. Hosp. Infant. Mex.]]></abbrev-journal-title>
<issn>1665-1146</issn>
<publisher>
<publisher-name><![CDATA[Instituto Nacional de Salud, Hospital Infantil de México Federico Gómez]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1665-11462019000400188</article-id>
<article-id pub-id-type="doi">10.24875/bmhim.19000089</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Leucemia agresiva de células natural killer en un paciente pediátrico]]></article-title>
<article-title xml:lang="en"><![CDATA[Agressive NK-cell leukemia in a pediatric patient]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rey-Helo]]></surname>
<given-names><![CDATA[Elianneth]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Pérez-Velásquez]]></surname>
<given-names><![CDATA[Rubén D.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cortés-Alva]]></surname>
<given-names><![CDATA[Deyanira]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Sistema Nacional para el Desarrollo Integral de la Familia Hospital del Niño DIF Servicio de Oncología Pediátrica]]></institution>
<addr-line><![CDATA[ Hidalgo]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Sistema Nacional para el Desarrollo Integral de la Familia Hospital del Niño DIF Servicio de Patología]]></institution>
<addr-line><![CDATA[ Hidalgo]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Sistema Nacional para el Desarrollo Integral de la Familia Hospital del Niño DIF Servicio de Oncología]]></institution>
<addr-line><![CDATA[ Hidalgo]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>08</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>08</month>
<year>2019</year>
</pub-date>
<volume>76</volume>
<numero>4</numero>
<fpage>188</fpage>
<lpage>192</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1665-11462019000400188&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1665-11462019000400188&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1665-11462019000400188&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen  Introducción:  Las neoplasias de células natural killer (NK) son poco frecuentes y representan &lt;5% de todas las neoplasias linfoides. Comprometen diferentes entidades clínicas, como la leucemia de células NK, que es una neoplasia hematológica altamente agresiva con un pronóstico precario, que se presenta en hombres jóvenes y se observa con mayor frecuencia en ascendencia asiática. El virus de Epstein-Barr (VEB) parece estar relacionado con la patogenia de esta leucemia.  Caso clínico: Se presenta el caso de un paciente de sexo masculino de 1 año y 7 meses de edad, quien inició su padecimiento con síndrome anémico, febril, infiltrativo e hiperleucocitosis. En el aspirado de médula ósea se detectaron blastos de morfología L2 (96%), inmunofenotipo CD56 (80.87%) y desoxinucleotidil transferasa terminal (84.11%). En la biopsia de médula ósea se identificó CD2+ membranoso, CD3+ citoplásmico y CD56+ membranoso; la serología para VEB fue positiva. El paciente recibió dos esquemas diferentes de quimioterapia basados en metotrexato, ifosfamida, etopósido, dexametasona y L-asparaginasa, y se documentó remisión parcial. Actualmente, se encuentra vivo con la enfermedad.  Conclusiones: La leucemia de células NK es rara en adultos jóvenes, pero aún más en pacientes en edad pediátrica. Además, es de muy difícil tratamiento, ya que solo se cuenta con algunos reportes de casos, la sobrevida es de semanas a meses y las oportunidades de tratamiento se limitan. Recientemente, se ha evidenciado la utilidad del trasplante de médula ósea alogénico o células de cordón umbilical, y se ha logrado una sobrevida a 2 años. Las posibilidades terapéuticas en estos pacientes se encuentran en estudio. Se espera lograr en un futuro cercano la remisión completa y sobrevida a 5 años.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract  Background:  Natural killer (NK) cell neoplasms are rare and represent &lt;5% of all lymphoid neoplasms. They involve different clinical entities, of which one is NK cell leukemia, a highly aggressive hematologic neoplasm with poor prognosis that presents in young men and is more frequently seen in Asian descent. Epstein-Barr virus (EBV) seems to be related to the pathogenesis.  Case report:  A male patient of 1 year and 7 months of age, who began his condition with anemic, febrile, infiltrative syndrome and hyperleukocytosis is described. Bone marrow aspirate showed L2 morphology blasts (96%), CD56 (80.87%) and terminal deoxynucleotidyl transferase (84.11%) immunophenotype. Bone marrow biopsy showed membranous CD2+, cytoplasmic CD3+ and membranous CD56+; serology positive to EBV. The patient received two different chemotherapy schemes based on methotrexate, ifosfamide, etoposide, dexamethasone and L-asparaginase, which resulted in partial remission. Currently, the patient lives with the disease.  Conclusions: NK cells leukemia is rare in young adults, but even more in pediatric patients, for which it is very difficult to treat because only a few cases have been reported in the literature, the survival varies from weeks to months and the chances of treatment are limited. Recently, the usefulness of allogeneic bone marrow transplantation or umbilical cord cells has been demonstrated, achieving a 2-year survival. The therapeutic possibilities in these patients are under study. In the near future, we hope to achieve the complete remission of the disease and a 5-year survival.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Leucemia]]></kwd>
<kwd lng="es"><![CDATA[Pediátrico]]></kwd>
<kwd lng="es"><![CDATA[Células asesinas naturales]]></kwd>
<kwd lng="es"><![CDATA[Pancitopenia]]></kwd>
<kwd lng="en"><![CDATA[Leukemia]]></kwd>
<kwd lng="en"><![CDATA[Pediatrics]]></kwd>
<kwd lng="en"><![CDATA[Natural killer cells]]></kwd>
<kwd lng="en"><![CDATA[Pancytopenia]]></kwd>
</kwd-group>
</article-meta>
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