Clinical history of thrombosis before diagnosis of overt myeloproliferative neoplasms in triple negative patients

Thromboses are the most important preventable risk factors for morbidity and mortality in myeloproliferative neoplasms (MPN). We here performed a retrospective cross sectional study of patients with a diagnosis of Philadelphia negative MPN and a prior history of thrombosis, analyzed from electronic charts. Among a cohort of 260 patients with MPNs (78PV, 102ET, 80 MF), forty four were found triple negative for JAK-2, calreticulin and MPL gene mutations. Sixty-nine (26.54%) patients (29F, 40M) had a personal past clinical history of arterial or venous thrombosis. Among patients with thrombosis, 13(18.8%) cases (11ET, 2MF) were triple negative (median age:60 years). Most events, in particular in triple negative patients, occurred within 18 months before overt MPN . At the time of thrombosis diagnosis, only a minority of patients showed blood tests abnormalities suggestive of MPN or indicating hematological consultation(Figure). Triple negative MPNs may represent a distinct entity with peculiar clinical course and risk factors.