MPN-U

Question 1

What is the definition of

MPN-U ?

Answer 1

• clinical, laboratory and morphologic findings of an MPN but fail to meet specific criteria for any one defined entity
  
  • or have features that overlap between 2 entities
• there are 3 groups in MPN-U
  
  • see p. 57

Question 2

What is the epidemiology

of MPN-U ?

Answer 2

• exact incidence is not known but may count for 10-15% of MPN
• if following exact criteria, may be <5% of all cases

Question 3

What is the localization of

MPN-U ?

Answer 3

• blood and bone marrow are the major sites of involvement
• later stages spleen and liver can as well

Question 4

What are the clinical features of

MPN-U ?

Answer 4

• similar to those of other MPNs
• prominent cytopenias or MDS features warrant exclusion of MDS/MPN or MDS

Question 5

When can a diganosis of MPN-U

not be made?

Answer 5

• if there is insufficient clinical data to make any type of designation
• if the bone marrow is of inadquate quality or or size for adequate evalutaion
• or if the patient received cytotoxic or growth factor therapy recently

Note: the report should indicate why MPN-U was diagnosed and which entities can be excluded by what is seen

Question 6

What mutations are often seen

in myeloid neoplasms that can indicate

clonality in the absence of traditional mutations ?

Answer 6

• ASXL1
• EZH2
• TET2
• IDH1
• IDH2
• SRSF2
• SF3B1

but must exclude that these are not CHIP etc

Question 7

What is important to remember

for MPN-U ?

Answer 7

• most cases represent early manifestations of ET, PMF or PV that are difficult to differentiate
• Note: there is no specific molecular alteration for MPN-U
  • JAK2, CALR or MPL mutations support that it is an MPN