[Mastocytosis].

Mastocytoses are diseases caused by proliferating mast cells infiltrating one or more organs. The spectrum of mastocytosis includes the cutaneous forms urticaria pigmentosa and solitary mastocytoma (about 90% of mastocytoses) and systemic forms affecting other organs. Infiltrates are most often found in the bone marrow, spleen, lymph nodes and liver, but any organ may be affected. Patients with systemic mastocytosis may or may not have urticaria pigmentosa. About 35% of patients without urticaria pigmentosa have an associated malignant haematological disease and a poor prognosis. Symptoms caused by mast cell mediator release are best treated with antihistamines, but several other drugs may be used if the response is unsatisfactory. Many antineoplastic drugs have been tried to combat aggressive mastocytoses and mast cell leukaemia, but the results have been disappointing.