Myelodysplastic/myeloproliferative Neoplasm, Unclassifiable (MDS/MPN-U): More Than Just a "Catch-All" Term? | Aplastic Anemia & MDS International Foundation

Myelodysplastic/myeloproliferative Neoplasm, Unclassifiable (MDS/MPN-U): More Than Just a "Catch-All" Term?

Journal Title: 
Best practice & research. Clinical haematology
Primary Author: 
Shallis, Rory M
Author(s): 
Rory M Shallis, Amer M Zeidan
Original Publication Date: 
Tuesday, June 2, 2020

The clinicopathology of MDS and MPN are not mutually exclusive and for this reason the category of myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) exists. Several sub-entities have been included under the MDS/MPN umbrella, including MDS/MPN-unclassifiable (MDS/MPN-U) for those cases whose morphologic and clinical phenotype do not meet criteria to be classified as any other MDS/MPN sub-entity. Though potentially regarded as a wastebasket diagnosis, since its integration into myeloid disease classification, MDS/MPN-U has been refined with increasing understanding of the mutational and genomic events that drive particular clinicopathologic phenotypes, even within MDS/MPN-U. The prototypical example is the identification of SF3B1 mutations and its durable association with MDS/MPN with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T), an entity previously buried within, but now a separate category outside of MDS/MPN-U. Continued and enhanced study of those entities under MDS/MPN-U, a perhaps provisional category itself, is likely to progressively identify commonality between many "unclassifiables" to establish a new classifiable diagnosis.

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