Mast Cell Burden in a Patient With Cutaneous Disease.

Mastocytosis is a disease characterized by the abnormal clonal proliferation of mast cells in skin and/or extracutaneous organs, often relating to activating mutations of c-KIT. Histopathology special stains, such as Giemsa, Leder, and Toluidine blue, are key for the diagnosis of cutaneous mastocytosis (CM). In adults, skin lesions can be associated with systemic disease. Tryptase is a diagnostic marker in mastocytosis and thought to reflect the burden of mast cell disease. In this report, we present a case of cutaneous mast cell disease with associated findings of elevated serum tryptase and mast cell infiltration of the bone marrow consistent with indolent systemic mastocytosis.