Non-EBV-Related Aggressive NK-Cell Leukemia: An Oncohematological Great Imitator.

Aggressive natural killer (NK)-cell leukemia (ANKL) is a very rare oncohematological disease among youngsters in Latin America. Its clinical picture imitates a variety of syndromes and diseases due to its pathophysiology. Its diagnosis is relatively simple due to the prominence of NK malignant cells in peripheral blood and its clinical aggressiveness. In certain circumstances though, the presence of blast NK cells and the natural course of the disease can be so modified by the treatment of one of the imitated diseases, especially when using steroids, that it becomes very difficult to diagnose early in its course. We present a case of a 16-year-old Mexican male who initiated symptoms imitating dengue to severe dengue for which he received steroids, apparently inducing a partial remission; he was then diagnosed as having community acquired pneumonia, then sepsis, septic shock w/disseminated intravascular coagulation, primary hemophagocytic syndrome, severe hepatitis, lupus and finally hyper IgE. It was not until 1 day before dying of hemorrhagic shock, a month after initiating symptoms, when the (re)emergence of blast NK cells in peripheral blood allowed the correct diagnosis to be made. Knowledge of ANKL pathophysiology may raise awareness of this multifaceted malignancy and may open up possibilities for its therapy. Gained knowledge can also be used for guiding NK cell evident aggressiveness against other malignancies.

Características citopatológicas de la leucemia aguda en el Hospital de Especialidades Pediátricas de Chiapas, México / Cytopathologic features of childhood acute leukemia at the Hospital de Especialidades Pediátricas, Chiapas, Mexico

Resumen: Introducción: Se desconocen las características citopatológicas de las leucemias agudas en pacientes de Chiapas, México, ya que es una población relativamente aislada con alto índice de consanguinidad, lo cual podría afectar la evolución y la respuesta terapéutica. Métodos: Se clasificaron morfológica, inmunofenotípica y genotípicamente 81 casos de leucemia aguda en pacientes atendidos en el Hospital de Especialidades Pediátricas de Chiapas, indicando riesgo al ingreso y situación al momento del estudio. Los resultados se comparan con información nacional e internacional pertinente. Resultados: Se encontró la siguiente proporción de tipos de leucemia aguda: leucemias B, 75.3%; mieloides, 16%; de células T, 3.7%; B-M, 3.7% y de células NK, 1.2%. Las alteraciones genéticas estuvieron presentes en 40.6% de las B y en 69% de las mieloides. La alteración genética se relacionó con la evolución del paciente a corto plazo en las leucemias tipo B; no así en las mieloides. En las B, los casos con el gen MLL alterado fallecieron en menos de un mes, los casos con la translocación t(1;19)(q23;p13) han tenido buena evolución, y aquellos con la t(12;21)(p13;q22) han tenido mala evolución a medio plazo. La hiperdiploidía se presentó en el 20% de los casos B; el 83% de ellos permanecen en remisión de 1 a 12 meses desde el diagnóstico. El 69% de los casos con leucemias mieloides falleció o abandonó el tratamiento en recaída de 15 días a 37 meses del diagnóstico. Conclusiones: La proporción de los diferentes tipos de leucemia aguda atendidas en el HEP es similar a la encontrada en otras partes del país. Su comportamiento y desenlace está relacionado con la presencia o ausencia de alteraciones genéticas específicas y no específicas.

Abstract: Background: Childhood acute leukemia cytological features are unknown in Chiapas, Mexico. Defining these features is important because this is a relatively isolated population with high consanguinity index, and these aspects could determine differences in responses to treatment and outcome. Methods: Eighty-one childhood acute leukemia cases treated at the Hospital de Especialidades Pediátricas in Chiapas were characterized by morphology, immunophenotype, genotype, initial risk assignment and status at the time of the study. Results: The proportion of leukemic cell types found in this study was B cell, 75.3%; myeloid, 16%; T cell, 3.7% and NK 1.2%. In B cell leukemia, genetic alterations were present in 40.6% of cases and had a specific outcome regardless of initial risk assessment. Cases with MLL gene alteration died within a month from diagnosis. Translocations were present in 17.5% B cases; t(1;19) was present in those with a favorable outcome. The t(12;21) translocation was related to initial remission and midterm relapse and dead. Hyperdiploidy was present in 20% of B cell cases with good outcome. In 38.5%of myeloid cases were translocations and karyotypic abnormalities. Short-term outcome in this group has been poor; 69% have died or abandoned treatment in relapse from 15 days to 37 months after diagnosis. Conclusions: Relative frequency of different types of acute leukemia in patients treated at a tertiary level pediatric hospital in Chiapas, Mexico, was similar to the one found in other parts of the country. Patients' outcome, under a standardized treatment, differs according to the group, the subgroup and the presence and type of genetic alterations.

[Cytopathologic features of childhood acute leukemia at the Hospital de Especialidades Pediátricas, Chiapas, Mexico]. / Características citopatológicas de la leucemia aguda en el Hospital de Especialidades Pediátricas de Chiapas, México.

BACKGROUND: Childhood acute leukemia cytological features are unknown in Chiapas, Mexico. Defining these features is important because this is a relatively isolated population with high consanguinity index, and these aspects could determine differences in responses to treatment and outcome. METHODS: Eighty-one childhood acute leukemia cases treated at the Hospital de Especialidades Pediátricas in Chiapas were characterized by morphology, immunophenotype, genotype, initial risk assignment and status at the time of the study. RESULTS: The proportion of leukemic cell types found in this study was B cell, 75.3%; myeloid, 16%; T cell, 3.7% and NK 1.2%. In B cell leukemia, genetic alterations were present in 40.6% of cases and had a specific outcome regardless of initial risk assessment. Cases with MLL gene alteration died within a month from diagnosis. Translocations were present in 17.5% B cases; t(1;19) was present in those with a favorable outcome. The t(12;21) translocation was related to initial remission and midterm relapse and dead. Hyperdiploidy was present in 20% of B cell cases with good outcome. In 38.5%of myeloid cases were translocations and karyotypic abnormalities. Short-term outcome in this group has been poor; 69% have died or abandoned treatment in relapse from 15 days to 37 months after diagnosis. CONCLUSIONS: Relative frequency of different types of acute leukemia in patients treated at a tertiary level pediatric hospital in Chiapas, Mexico, was similar to the one found in other parts of the country. Patients' outcome, under a standardized treatment, differs according to the group, the subgroup and the presence and type of genetic alterations.