A Case of Erythrocytosis in a Patient Treated with an Aromatase Inhibitor for Breast Cancer

Box 1

Differential diagnosis of erythrocytosis. EPO indicates erythropoietin; 2,3-DPG, 2,3-disphosphoglycerate.

Secondary polycythemia

         Appropriately increased EPO

      Pulmonary disease

      Cyanotic heart disease

      Obstructive sleep apnea

      Carbon monoxide, for example, smoking

      High altitude

         Inappropriately increased EPO

      Tumour polycythemia, for example, renal cell carcinoma, hepatocellular carcinoma

      Renal lesions, for example, polycystic kidney disease, kidney transplant

      Endocrinopathies, for example, Cushing syndrome, primary aldosteronism

         Drug-induced polycythemia, for example, exogenous EPO, androgens

Primary polycythemia

         Polycythemia vera

         Congenital polycythemias

      Abnormalities of oxygen sensing, for example, Chuvash polycythemia

      Alterations in oxygen affinity, for example, high affinity hemoglobins, methemoglobinemia

      Low 2,3-DPG