How would you manage a patient with polycythemia and MPN symptoms (aquagenic pruritus, fatigue) that is JAK2/CALR/MPL negative but peripheral blood NGS positive for IDH2?

I would approach this through the framing of a polycythemia/erythrocytosis workup and then consider MPN-related interventions if a diagnosis is made! This is an excellent review that provides an overview of erythrocytosis investigation (Noumani et al., PMID 38695361). In brief, I would be thinking about:

1. Are there other abnormalities on complete blood work (leukocytosis, abnormal WBC differential, thrombocytosis) that are concerning for an MPN?
2. Does the patient have other etiologies for polycythemia that would be secondary (sleep apnea, heart disease, testosterone use)?

With the currently provided information (polycythemia, no JAK2 mutation, normal EPO level), this patient would not meet criteria for PV by ICC or WHO (Arber et al., PMID 357...