A 49-year old man was admitted to the Korea university hospital, department of surgery, for evaluation of anterior neck mass which was slowly growing for five years. His past history was unremarkable except for known hypertension for several years. Physical examination revealed high blood pressure, measuring 180 mmHg in systolic phase and 120 mmHg in diastolic phase. A soft nontender mass was palpated at anterior neck just above the sternal notch with smooth surface and its size was about 4 x 5 cm in cross. On laboratory examination, diabetic evidence such as high blood sugar (FBS 170 mg/dl, PP2hr. 234 mg/dl) and glucosuria. The CBC finding suggested polycythemia with high hemoglobin (18.0 g/dl) and hematocrit (54%) levels. The differential count and platelet count were within normal limits.