Functional Mediastinal Pheochromocytoma
A 36-year-old man visited the emergency department. He had suffered from a sudden onset of chest pain, headache, palpitation, and dizziness. His pulse was regular, bounding, and at a rate of 119 per minute, and his blood pressure was at 190/120 mmHg. Electrocardiography and echocardiography were normal. Chest X-ray showed an oval-shaped mass lesion on the left paravertebral area (). Chest computed tomography (CT) and magnetic resonance imaging (MRI) showed a left paravertebral mass in the region of T4-T6, measuring at 3×6 cm, which was not invasive to the adjacent organs (). There was no specific finding on abdomen CT. The biochemical studies showed elevated levels of serum norepinephrine (12.905 ng/mL; normal limit [nl], 0 to 0.8 ng/mL), urine norepinephrine (4,946 µg/day; nl, 15 to 80 µg/day), urine metanephrine (4.2 mg/day; nl<0.8 mg/day), and urine vanillylmandelic acid (26.6 mg/day; nl, 0 to 8 mg/day). The serum and urine epinephrine levels were normal. The presence of the tumor was confirmed using an I-123 metaiodobenzylguanidine (MIBG) scan, along with its isolated nature (). In order to control the blood pressure and prepare for surgery, we administered α and β blocking agents to the patient. During the first three weeks, Concor (5 mg), Norvasc (5 mg), Atacand (8 mg), and Xyrem (0.25 mg) were administered. When visited the outpatient department, his blood pressure was near normotensive, but tachycardia and chest discomfort were still present. Therefore, we changed the medication to Cardura-XL (4 mg) for five weeks. The patient no longer felt chest discomfort, but tachycardia was still present. The heart rate was controlled (100 beat/min) after we administered Concor (2.5 mg). Two months after his first visit, we performed the operation. The tumor was found lying on the left paravertebral sulcus, which was hypervascular and well demarcated (). We performed thoracoscopic resection, but there were transient changes in the blood pressure, which ranged from 130/90 to 200/120 mmHg; therefore, we converted to thoracotomy. In the intraoperative period, we controlled the blood pressure with Brevibloc and Perdipine. After the tumor was resected, the blood pressure dropped sharply. Therefore, we stopped administering antihypertensive drugs, and then the blood pressure remained stable. The resected tumor measured 6.5×4.0×3.0 cm and weighed 47.5 g. Histopathological examination confirmed the tumor to be pheochromocytoma (). During the postoperative period, the patient remained normotensive without the need of antihypertensive drugs. He was discharged on the postoperative day 8. Two months later, the follow-up biochemical studies showed decreased levels of serum norepinephrine (1.108 ng/mL), urine norepinephrine (149.3 µg/day), urine metanephrine (1 mg/day), and urine vanillylmandelic acid (7.1 mg/day). The patient was asymptomatic with normal blood pressure and without taking antihypertensive drugs for more than 1 year.