Rare Hematological Malignancies in Children

Among the subtypes of pediatric leukemia, acute lymphoid (ALL) and acute myeloid leukemia (AML) comprise the majority of diagnoses. This chapter addresses several of the less common subtypes, including juvenile myelomonocytic leukemia (JMML), chronic myeloid leukemia (CML), and acute megakaryoblastic leukemia (AMKL), many of which are biologically and genetically unique. The first insight into genomic aberrations responsible for JMML came from an observation that children with neurofibromatosis (NF) type I are predisposed to hematological malignancies. The only curative option for aggressive cases of JMML is hematopoietic stem cell transplantation (HSCT). The median age at diagnosis of CML is 60-65 years, making it a rare disease in pediatric patients. However, children with CML have benefitted from clinical trials performed in adults leading to the universal use of tyrosine kinase inhibitor (TKI) therapy for most children with CML.