Mastocytosis: Overview of Diagnosis and Classification

Mastocytosis is defined as a heterogeneous group of disorders characterized by clonal expansion and aberrant activation of mast cells. Most cases are associated with gain-of-function mutations in KIT, the receptor for stem cell factor, the major cytokine involved in mast cell growth and differentiation. While a rare disease, it is increasingly diagnosed due to the refinements in diagnostic criteria and increased physician and patient awareness. Novel therapeutic approaches targeting mast cell survival and activation makes it important to correctly diagnosing the disease. This chapter serves as an introduction on the symptomatology, diagnostic criteria, classification, and treatment of mastocytosis, which are discussed in more detail in other chapters of the book.