Major criterion | |
1. | Presence of multifocal, dense mast cell infiltrates (>15 in aggregates) in bone marrow or other extracutaneous organs |
Minor criteria | |
1. | >25% mast cells spindle-shaped or with abnormal morphology in bone marrow or other extracutaneous organs. |
2. | Detection of c-kit point mutation at codon 816 in bone marrow, blood or extracutaneous organs |
3. | Mast cells that coexpress CD117 with CD2 and/or CD25, in bone marrow or extracutaneous organs |
4. | Persistent increased serum total tryptase level (>20 ng/ml) |