Myeloproliferative Disorders in Non-Down Syndrome Patients

Myeloproliferative neoplasms (MPNs) are characterized by clonal hematopoiesis and aberrant proliferation of one or more myeloid lineages. This chapter will review the clinical presentation and diagnostic approaches of children/young adults with myeloproliferative disorders (MPDs). Emphasis in the first section of the chapter will be on MPNs that present in infants and toddlers as well as those that occur in children with constitutional disorders like Down syndrome or Noonan syndrome. Clinical presentation and therapeutic management will be reviewed and treatment approaches highlighted for these related disorders. The second half of the chapter will focus on the pediatric presentation and management of MPN’s typically seen in adulthood, namely chronic myeloid leukemia (CML), essential thrombocytosis (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). It is important for pediatric providers to be aware of both the diagnostic criterion and the nuances of pediatric presentation that might make diagnosis of these classically adult derived MPNs challenging. Moreover, as unique therapeutic considerations exist for pediatric patients with adult MPNs, largely due to the young age of diagnosis and potential need for lifelong treatment, comparison of pediatric versus adult therapeutic approaches for a given diagnosis will be discussed.