Table 5.
Shared and unique clinicopathologic features between SM and various myeloid neoplasms: potential endpoints for assessment of response in the myeloid neoplasm
| Myeloid neoplasm | Shared features with advanced SM | Distinguishing features from pure SM | Unique myeloid neoplasm endpoints to measure | Published response criteria for the myeloid neoplasm |
|---|---|---|---|---|
| MDS | Cytopenias | Dysplasia, increased myeloblasts, ring sideroblasts | Reduction in dysplasia, myeloblasts, % ring sideroblasts | Modified IWG criteria56 |
| CMML | Cytopenias, organomegaly/LAN | Dysplasia, monocytosis, increased myeloblasts, ring sideroblasts | Reduction in dysplasia, monocytosis, myeloblasts, % ring sideroblasts | Modified IWG criteria56 |
| MDS/MPN (excluding CMML) | Cytopenias, organomegaly/LAN | Dysplasia, leukocytosis | Reduction in dysplasia, myeloblasts, % ring sideroblasts | None |
| HES or CEL-NOS, or myeloid neoplasms with eosinophilia and rearrangement of PDGFRA/B or FGFR1 | Eosinophilia, organomegaly/LAN, elevated tryptase level | ± Leukocytosis PDGFRA/B, FGFR1 rearranged* | Reduction in leukocytosis & eosinophilia; FISH or PCR for PDGFRA/B, FGFR1-rearranged | None; a proposed definition includes: complete hematologic response (CR): normalization of eosinophilia, and if present, leukocytosis; partial hematologic response (PR): ≥ 50% improvement of absolute eosinophilia |
| Myelofibrosis (primary or secondary) | Cytopenias, organomegaly, marrow fibrosis | Leukoerythroblastosis, increased myeloblasts, JAK2 V617F mutation, ? increased LDH level | Reduction in leukoerythoblastosis, myeloid immaturity, and % peripheral blood and BM myeloblasts; reduction of JAK2 V617F allele burden by quantitative RT-PCR | IWG-MRT response criteria57 |
| cute myeloid leukemia | Cytopenias, ± organomegaly | Increased myeloblasts; recurrent cytogenetic abnormalities (eg, t(8.21); t(15;17); inv(16) or t(16;16); AML-associated mutations such as FLT3, NPM1, and CEBP-α | Reduction in myeloblasts; remission of AML-related cytogenetic abnormalities | IWG response criteria58 |
*
The presence of a PDGFRA/B or FGFR1-rearranged myeloid neoplasm with eosinophilia with KIT D816V-positive SM is extremely rare.
CEL-NOS, chronic eosinophilic leukemia-not otherwise specified; FISH: fluorescent in situ hybridization; HES, hypereosinophilic syndrome; LAN, lymphadenopathy; LDH, lactate dehydrogenase; RT-PCR, reverse transcription polymerase chain reaction.