Abstract • 17

Mastocytosis is a multi-system disease, the diagnosis of which relies on the demonstration of a significant increase in mast cells in the tissues involved. This disease is observed in both adults and in infants and children. In adults, mastocytosis is usually progressive, and in a significant number is associated with dysmyelopoiesis. In children, mastocytosis may disappear in 50% or more of those diagnosed. The most common manifestation in children is urticaria pigmentosa. Bone marrow involvement is much less common than in adults. Since 1995, several mutations have been identified in c-kit, the receptor for stem cell factor. Preliminary evidence suggests that the presence or absence of specific mutations in children may correlate with prognosis.