Background: Systemic mastocytoses are a group of diseases, which are characterized by accumulation and unusual growth of mast cells infiltrating two different organs or types of tissue. Two case reports are introduced.
Classification: According to the new WHO classification of 2000, mastocytoses are separated into cutaneous and systemic mastocytoses. Systemic mastocytosis is subdivided into an indolent course with good prognosis and four subgroups with poor prognosis (systemic mastocytosis with associated clonal hematologic non-mast-cell disease, aggressive systemic mastocytosis, mast cell leukemia, and mast cell sarcoma).
Genetics: Systemic mastocytoses are clonal disorders of mast cells and their progenitor cells, which may show point mutations of the protooncogene c-kit. This gene codes for the stem cell receptor (CD117).
Therapy: Therapy of systemic mastocytosis depends on patient's symptoms. There is no known cure of the disease. Besides diet and avoidance of skin irritations, symptoms are treated with H(1)- or H(2)-blockers, steroids, leukotriene receptor antagonists, and PUVA therapy. If patients suffer from systemic reactions such as hypotension or syncope, epinephrine solution should be prescribed for emergency use.