In adults with suspected SM, a thorough BM investigation is recommended when one or more of the following parameters are identified: typical skin lesions (mastocytosis in the skin); a clearly elevated basal serum tryptase level; a KIT mutation (usually KIT D816V); and/or typical clinical sign or symptoms that have no known etiology, such as unexplained osteoporosis (especially in men), unexplained lymphadenopathy and/or splenomegaly, or unexplained repeated anaphylactic episodes after bee or wasp stings (Table 1) [1,2,3,4,11,13,14,15,16,17,18,19,20]. Here, KIT is linked to systemic mastocytosis.