Secondary erythrocytosis is most commonly a normal physiologic response to hypoxia, but in less frequent circumstances can also present as a paraneoplastic syndrome due to autonomous production of erythropoietin. Paraneoplastic erythropoietin production has been associated with renal cell carcinoma, hepatocellular carcinoma, and uterine leiomyomas. In rare cases, this can also be seen in CNS hemangioblastomas. Here, we report a case of a patient with remote history of resected astrocytoma who presented with symptoms concerning for astrocytoma recurrence. On laboratory evaluation, she was noted to have erythrocytosis. Workup revealed an elevated erythropoietin level suggesting secondary erythrocytosis, but without any apparent contributing etiology with no history of smoking, cardiopulmonary disease, or radiographic evidence of a tumor apart from MRI findings concerning for recurrence of her astrocytoma. Ultimately, surgical pathology of her brain tumor revealed a CNS hemangioblastoma and erythrocytosis resolved with resection of the tumor.

Keywords: Erythrocytosis; Secondary erythrocytosis; Hemangioblastoma; Paraneoplastic