Systemic mastocytosis with an associated myeloid neoplasm (SM-AMN)
| 1. Meets the diagnostic criteria for SM |
| 2. Meets the criteria for an associated myeloid neoplasm (eg, CMML or other MDS/MPN, MDS, MPN, AML, or other myeloid neoplasm)* |
| 3. The associated myeloid neoplasm should be fully classified according to established criteria† |
| 1. Meets the diagnostic criteria for SM |
| 2. Meets the criteria for an associated myeloid neoplasm (eg, CMML or other MDS/MPN, MDS, MPN, AML, or other myeloid neoplasm)* |
| 3. The associated myeloid neoplasm should be fully classified according to established criteria† |
High degree of suspicion can be raised by the presence of monocytosis, eosinophilia, splenomegaly, elevated LDH, high KIT D816V variant allele frequency, and additional somatic mutations in genes associated with myeloid malignancies (particularly if occurring in combination) as they could be signs of an AMN.
If eosinophilia is present, the presence of tyrosine kinase gene fusions associated with M/LN-eo should be excluded. Although usually mutually exclusive, rare cases with both a KIT mutation and a gene fusion associated with M/LN-eo have been reported. In these rare instances, the M/LN-eo would represent the SM-associated AMN, but it is recommended assigning such cases only in instances in which both a KIT mutation and an M/LN-eo gene fusion are present.