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Occult myeloproliferative neoplasms: not so occult any more
  1. Dhauna Karam1,
  2. Veena Iyer2,
  3. Bharat Agrawal2
  1. 1 Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
  2. 2 Captain James A. Lovell Federal Health Care Center, North Chicago, Illinois, USA
  1. Correspondence to Dr Dhauna Karam, dhauna.karam{at}


Non-cirrhotic, non-malignant portal vein thrombosis (PVT) is commonly secondary to inherited or acquired prothrombotic states. However, even after extensive workup, 25% of patients with PVT have no apparent prothrombotic aetiology identified (idiopathic PVT). Inherited conditions include factor V Leiden, PT mutation and protein C/S/AT deficiency. Acquired conditions include APS, PNH and BCR-ABL 1-negative myeloproliferative neoplasms (MPN). BCR-ABL-1 negative MPNs are the most frequent underlying prothrombotic risk factor for PVT (15%–30%). However, peripheral blood counts often remain within normal ranges in these patients with MPN because of portal hypertension sequel. Despite suggestive features of MPN in bone marrow, these patients lack adequate diagnostic criteria and are classified as occult MPN. The discovery of recurrent molecular abnormalities such as CALR gene exon 9 mutation presented a crucial advance in the diagnosis of occult MPNs. In our patient, the diagnosis of MPN was made on this basis, despite lack of peripheral evidence of MPN.

  • haematology (incl blood transfusion)
  • medical management
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  • Contributors All authors have contributed to the manuscript individually and agree with the conclusion.

    DK, PMK and BA were involved in conception and design of the work. DK and VI worked together to draft the article and complete writing the manuscript. PMK and BA critically revised the article and approved the final version to be published.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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