RT Journal Article SR Electronic T1 Aggressive Merkel Cell Carcinoma After Janus Kinase Inhibitor Ruxolitinib for Polycythemia Vera JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 1667 OP 1669 DO 10.21873/invivo.11653 VO 33 IS 5 A1 MARCO RASTRELLI A1 BEATRICE FERRAZZI A1 SAVERIA TROPEA A1 ALESSANDRA COSTA A1 SILVIA FINOTTO A1 DARIO MARINO A1 LUCA CAMPANA A1 PAOLO DEL FIORE A1 CARLO RICCARDO ROSSI A1 MAURO ALAIBAC YR 2019 UL http://iv.iiarjournals.org/content/33/5/1667.abstract AB Merkel cell carcinoma (MCC) is a rare neuroendocrine carcinoma of the skin. It is highly aggressive and represents the second most common cause of skin cancer-related death. Ruxolitinib is an orally administered selective inhibitor of Janus associated kinases1 and 2, which is used in the management of patients with symptomatic myelofibrosis and polycythemia vera who are non-responders or intolerant to hydroxyurea. Herein, we report the case of a 47-year-old woman with a 14-year history of chronic myeloproliferative syndrome initially treated with hydroxyurea for 4 years. She was then enrolled in the Response trial and treated for 7 years with ruxolitinib subsequently developing an MCC. This report shows the possibility of development of MCC in patients treated with ruxolitinib. Periodic skin examination is indicated in patients who undergo ruxolitinib therapy, especially if they have a history of skin cancer; dermatologists and oncohematologists should be aware of this possibility in order to introduce appropriate preventive strategies.