mast leukocyte -->
basophilic leukocyte
medical dictionary

A polymorphonuclear leukocyte characterised by many large, coarse, metachromatic granules (dark purple or blue-black when treated with Wright's or similar stains) that usually fill the cytoplasm and may almost mask the nucleus; these leukocyte's are unique in that they usually do not occur in increased numbers as the result of acute infectious disease, and their phagocytic qualities are probably not significant; the granules, which contain heparin and histamine, may degranulate in response to hypersensitivity reactions and can be of significance in general inflammation.

Synonyms: basocyte, basophilocyte, mast leukocyte.

(05 Mar 2000)