Table 5.
Refined Classification and Criteria for Advanced SM, Including SM-AHN, ASM, and MCL.
| Category | Subvariant | Defining Key Features (Criteria) |
|---|---|---|
| SM-AHN | According to SM variant: | |
| BMM-AHN | WHO criteria (consensus criteria) for SM variants | |
| ISM-AHN | ||
| SSM-AHNa | ||
| ASM-AHN | ||
| MCL-AHN | ||
| According to the AHN: | ||
| SM with myeloid AHN | WHO criteria for myeloid AHN type | |
| (SM-CMML, SM-AML, …) | ||
| SM with lymphoid AHN | WHO criteria for lymphoid AHN type | |
| (SM-ALL, SM-MM, …) | ||
| ASM | According to a previous MC neoplasm: | |
| Primary ASM | No previous SM known | |
| Secondary ASM | Previous BMM, ISM, SSM, … | |
| According to an AHN | ||
| ASM without AHN | ||
| ASM-AHN | WHO criteria for AHN | |
| According to signs of progression: | ||
| ASM | <5% MC in BM smears | |
| ASM in transformation | 5%–19% MC in BM smears | |
| (=ASM-T) | ||
| MCL | According to a previous MC neoplasm | |
| Primary MCL | No previous MC disease known | |
| Secondary MCL | Previous BMM, ISM, SSM, MCS, … | |
| According to an AHN | ||
| MCL without AHN | ||
| MCL-AHN | WHO criteria for AHN | |
| According to organ damage | ||
| Chronic MCL | No C-finding(s) | |
| Acute MCL | One or more C-finding(s) | |
| According to blood involvement | ||
| Aleukemic MCL | MC <10% of blood leukocytes | |
| Leukemic MCL | MC ≥10% of blood leukocytes |
aSSM-AHN is an extremely rare condition as signs of myeloproliferation and/or dysplasia will be regarded as sign of the (myeloid) AHN in almost all cases. However, SSM may still be diagnosed in a patient with AHN, for example, when the AHN is a lymphoid neoplasm (eg, SSM-CLL).
AHN = associated hematologic neoplasm; ALL = acute lymphoblastic leukemia; AML = acute myeloid leukemia; ASM = aggressive SM; BMM = bone marrow mastocytosis; CMML = chronic myelomonocytic leukemia; ISM = indolent SM; MCL = mast cell leukemia; MCS = mast cell sarcoma; MM = multiple myeloma; SM = systemic mastocytosis; SSM = smoldering SM; WHO = World Health Organization.