Clinicopathological characterisation of myeloproliferative neoplasm‐unclassifiable (MPN‐U): a retrospective analysis from a large UK tertiary referral centre

Abstract

Myeloproliferative neoplasm-unclassifiable (MPN-U) presents an MPN-type phenotype that fails to meet diagnostic criteria for other MPN variants. Variability in the clinicopathological phenotypes presents many challenges. Amongst a registry cohort of 1512 patients with MPN, 82 with MPN-U were included, with a median (range) age of 49Á7 (13-79) years. Albeit heterogeneous, common presentation features included raised lactate dehydrogenase, thrombocytosis and clustered/pleomorphic megakaryocytes on trephine biopsy. Thrombosis was common (21%), necessitating vigilance. The median event-free survival was 11Á25 years (95% confidence interval 9Á3-not reached), significantly shortened in cases with lower platelet counts (<500 9 10 9 /l) and a leucocytosis (≥12 9 10 9 /l) at presentation. Generation of potential MPN-U prognostic scores is required.

The Classification of Myeloproliferative Neoplasms: Rationale, Historical Background and Future Perspectives with Focus on Unclassifiable Cases

“…A consistent proportion of MPNs nonetheless escapes any attempt of classification and may represent a persistence of poorly characterized subsets of myeloid neoplasms. These conclusions are in keeping with a recent study from Deschamps et al [37], which described the clinical, pathological, and molecular features of a series of 82 MPN-Us. In this cohort, the median age at diagnosis was 49 years (range: 13-79), with a slight female predominance ( ), while 20/82 (24.4%) cases were TN; a subset of patients underwent further investigation, which allowed the identification of variants affecting TET2, ASXL1, SRSF2, and RUNX1.…”

Fifth-week immunogenicity and safety of anti-SARS-CoV-2 BNT162b2 vaccine in patients with multiple myeloma and myeloproliferative malignancies on active treatment: preliminary data from a single institution

“…Combining cellular and humoral measures of vaccine efficacy may increase the ability to predict the risk of COVID-19. Evidence exists of robust memory T-cell responses in patients with MPN following SARS-CoV-2 infection [ 37 ]. The extent and robustness of such T-cell response after vaccination with BNT162b2 is a crucial point to verify in both MM and MPM patients.…”

How I manage myeloproliferative neoplasm‐unclassifiable: Practical approaches for 2022 and beyond

“…Although not clinically validated in an MPN‐U cohort, we utilise this screen to assess symptom burden in patients with MPN‐U which, at least in our experience, may be significant and discordant with disease phenotypic findings. In the cohort described by Deschamps et al, 4 approximately one‐third of patients had pruritus or constitutional symptoms. Only a limited set of patients had MPN‐SAF TSS scores performed but the range of scores was highly variable (cumulative score 0–73/100), highlighting significant symptomatology in some.…”

“…This remains a major unmet need. In the cohort described by Deschamps et al, 4 with a median follow‐up of just over 5 years, the median EFS was 11.25 years overall. The predictive role of mutational and cytogenetic analysis as a prognostic tool in MPN‐U remains unclear, limited by the relatively small number of patients.…”

“…Often, MPN‐U presents in a heterogeneous manner and hence clinical approaches are frequently highly individualised. The disease course can clearly be complicated by significant symptom burdens and splenomegaly, an increased risk of thrombosis and an inherent risk of blastic transformation 4,5 . In the series highlighted above, 8.5% of patients transformed to accelerated (AP) or blast phase (BP).…”