Study of Cellular Heterogeneity in Patients With Mastocytosis

Inclusion Criteria: * Criteria related to the study population: * Subject affiliated with a social security or insurance scheme * Subject who has given written consent to his participation in the study * Criteria related to the studied pathology: * Subject diagnosed with isolated cutaneous or indolent systemic mastocytosis with associated skin involvement defined according to World Health Organization criteria (and/or international criteria for cutaneous mastocytosis) * Subjects whose KIT mutation status is known in the skin, bone marrow, and blood Exclusion Criteria: * Criteria related to the study population: * Sun exposure of the biopsied areas expected within the 4 weeks preceding * Subjects who have had exposure to sunlight or artificial UV radiation within the 2 weeks preceding inclusion at the biopsied areas * Adult patients under legal protection, guardianship, or curatorship * Pregnant or lactating women * Criteria related to the studied pathology: * Subjects with an advanced version of the pathology or advanced systemic mastocytosis (SAMA) * Subjects with a known history of allergy or intolerance to local anesthetics * Subjects who have previously shown abnormalities in skin healing or any other contraindication to skin biopsy * Subjects with recognized addiction to alcoholism or drug abuse * Subjects with a hereditary or acquired disorder of hemostasis * Subjects with a severe or acute chronic condition judged by the investigator as incompatible with the trial * Subjects presenting a clinically incompatible immune deficiency with the study * Patients without a well-established diagnosis of mastocytosis * Patients included in a therapeutic study for indolent systemic mastocytosis * Treatment-related criteria: * Any topical or systemic treatment for atopic dermatitis (including phototherapy) ongoing or stopped at least 14 days before the inclusion visit * Systemic corticosteroids within the 4 weeks preceding the inclusion visit * Ongoing systemic treatment likely to interfere with the healing process * Subjects who have undergone physical treatment (radiotherapy, etc.) on the biopsy area in the past 6 months * History of treatment or concomitant treatment that may interfere with the conduct of the study as determined by the investigator