Diagnosis of mastocytosis: value of cytochemistry and immunohistochemistry.

The diagnosis of mastocytosis or mast cell disease may be difficult sometimes because of the wide variety of clinical presentation, abnormal morphology of mast cells, and variation in histologic features which may mimic varieties of other diseases. Over the years, several cell type specific cytochemical and immunochemical markers have been used for the identification of hematopoietic cells in order to establish the accurate diagnosis of mastocytosis and their associated hematologic diseases. Cytochemical stain for aminocaproate esterase is the most specific enzyme marker for identification of mast cells on cytologic specimens and the immunohistochemical stain for tryptase and/or c-kit has also been established as a sensitive and specific marker for mast cells in paraffin sections.