Proposed revised classification of systemic mastocytosis (SM)
| Class . | Name . | Criteria . |
|---|---|---|
| I | Indolent systemic mastocytosis (ISM) | Meets criteria for SM; no “C” findings; no evidence of SM-MDS, SM-CMML, SM-AL, or AML with BM mastocytosis; minimal or no MPN features |
| II | Smoldering systemic mastocytosis (SSM) | As above for ISM; 2 or more “B” findings |
| III | Aggressive systemic mastocytosis (ASM) | Meets criteria for SM; no evidence of SM-MDS, SM-CMML, SM-AL, or AML with BM mastocytosis; 1 or more “C” findings; MPN features allowed |
| IV | Systemic mastocytosis associated with myeloproliferative neoplasm, unclassifiable (SM-MPN) | No “C” findings |
| Class . | Name . | Criteria . |
|---|---|---|
| I | Indolent systemic mastocytosis (ISM) | Meets criteria for SM; no “C” findings; no evidence of SM-MDS, SM-CMML, SM-AL, or AML with BM mastocytosis; minimal or no MPN features |
| II | Smoldering systemic mastocytosis (SSM) | As above for ISM; 2 or more “B” findings |
| III | Aggressive systemic mastocytosis (ASM) | Meets criteria for SM; no evidence of SM-MDS, SM-CMML, SM-AL, or AML with BM mastocytosis; 1 or more “C” findings; MPN features allowed |
| IV | Systemic mastocytosis associated with myeloproliferative neoplasm, unclassifiable (SM-MPN) | No “C” findings |
SM indicates systemic mastocytosis; MPN, myeloproliferative neoplasm; MDS, myelodysplastic syndrome; CMML, chronic myelomonocytic leukemia; AL, acute leukemia; AML, acute myeloid leukemia; and BM, bone marrow.