Evidence of jak2 val617phe positive essential thrombocythemia with splanchnic thrombosis during estroprogestinic treatment.

The discovery of the Janus kinase 2 Val617Phe mutation has brought new insights into the development of myeloproliferative disorders; however, the pathogenesis of essential thrombocythemia and its related thrombotic complications has not been completely understood. Although the Janus kinase 2 Val617Phe mutation confirms the initially suspected clonal character of the disease, factors influencing clonal transformation and expansion in the bone marrow have not been fully detected. Furthermore, patients affected by essential thrombocythemia who are carriers of the Janus kinase 2 Val617Phe mutation show a higher incidence of venous thromboembolism both before, and at the time of diagnosis, compared with noncarriers, and recent evidence of splanchnic and cerebral vein thrombosis in carriers of the Janus kinase 2 Val617Phe mutation has been reported. The intake of oral contraceptives is a strong and independent risk factor for venous thromboembolism. In addition, in-vitro tests showed both an altered primary haemostatic plug formation and enhanced platelet aggregation in patients taking such drugs. Little is known, though, about the influence of steroid hormones on both megakaryopoiesis and platelet function in patients with the Janus kinase 2 Val617Phe mutation. Herewith, we report the case of a 30-year-old woman who took a third generation oral contraceptive for 5 months and developed an essential thrombocythemia with spleno-portal axis and superior mesenteric vein thrombosis. She was found to carry the kinase gene Janus kinase 2 mutation.