To the Editor.
—A case of erythrocytosis was managed successfully by percutaneous aspiration of a renal cyst.
Report of a Case.
—A 66-year-old woman was referred on Aug 12, 1979, for evaluation of erythrocytosis. Twenty-five years previously, she had had a hysterectomy for fibroids, and in 1974, she underwent an operation for "pus on the left kidney." She consulted her personal physician for complaints of weakness and anorexia. A high hemoglobin level was discovered. Findings from a physical examination showed a well-developed woman with a blood pressure of 160/100 mm Hg. Except for glaucoma in the left eye, findings from the remainder of the physical examination were normal.Her packed red cell volume was 52 vol%, and her hemoglobin level was 18 g/dL. Her WBC count was 6,200/μL, and the platelet count was 280,000/μL. Her serum creatinine level, arterial blood gas level, and oxygen dissociation curve were normal. Her hemoglobin