ACUTE LEUKEMIC TRANSFORMATION OF SYSTEMIC MAST-CELL DISEASE - PARTIALREMISSION UNDER LOW-DOSE CYTOSINE-ARABINOSIDE

Systemic mastocytosis classically occurs as two variants, a ''benign'' variant whose symptoms are mainly due to mastocyte degranulation and a ''malignant'' variant characterized by predominant tumoral symptoms (infiltration of the liver, lymphoid organs, and hematopoetic bone mar row with or without concomitant hematologic disorders). A new classifi cation into four stages was developed in the late 1980s: stage I, syst emic indolent mastocytosis; stage II, mastocytosis with an associated hematologic disorder; stage III, lymphadenopathic mastocytosis with eo sinophilia; and stage IV, mast cell leukemia. Mean survival after diag nosis is three years in stages II through IV. This, together with the low incidence of these disorders, is a significant obstacle to therape utic trials, and consequently anecdotal reports of cases that respond to therapeutic efforts deserve attention. A patient with stage III dis ease at diagnosis was followed for several years. Factors of adverse p rognostic significance;were present initially. The patient was elderly , in poor general condition, and wanted to be treated at home. Low-dos e cytosine arabinoside was given: This treatment has been used in acut e myeloblastic leukemia in elderly patients but not in acute leukemic transformation of systemic mastocytosis. A good-quality partial remiss ion was obtained and lasted three months. Cytosine arabinoside deserve s to be tried in other elderly patients, perhaps in combination with o ther agents, such as interferon-alpha or, particularly in patients wit h neutropenia, GM-CSF.