French guidelines for the management of nonadvanced mastocytosis in adults.

Mastocytosis is a rare disease caused by abnormal mast cell accumulation/proliferation in various organs/tissues. Its clinical features exhibit significant variability irrespective of its clinical presentation, classification, global survival or impact on quality of life (QOL). For example, 15% of adult patients present isolated skin mastocytosis, called cutaneous mastocytosis (CM), while 85% have systemic mastocytosis (SM), with the most frequent type of skin lesions being systemic mastocytosis with cutaneous infiltration. In addition, regardless of the location of the mast cells or whether the CM or SM is isolated (whether with or without associated skin involvement), symptoms due to mast cell activation can vary in severity and may be life-threatening. All these manifestations can impose additional stress on patients.This protocol is a compendium of evidence-based recommendations formulated by experts. Its purpose is to assist clinicians in the management of these rare and frequently complex diseases. It describes the management of adult patients with nonadvanced or indolent mastocytosis (CM), CM with primary MCAS, indolent systemic mastocytosis, bone marrow mastocytosis, and smoldering mastocytosis.