Pazopanib-related secondary polycythemia in metastatic myxofibrosarcoma: A case report and review of the literature.

We postulated a Pazopanib-related secondary erythrocytosis, since Hb and Hct levels increased from baseline during treatment, then normalized when Pazopanib was discontinued. We used the Naranjo Nomogram to assess the correlation between the adverse effect and Pazopanib, the correlation was "Probable", a score of 5. To the best of our knowledge, this is the first case report of Pazopanib-related secondary polycythemia in a patient with sarcoma. It is important to pay attention to blood count and to any symptoms potentially related to erythrocytosis in patients treated with TKIs.