Ann Thorac Surg 2006;82:2304
© 2006 The Society of Thoracic Surgeons
Images in Cardiothoracic Surgery
An Extrapericardial Middle Mediastinal Pheochromocytoma
Karl L. Uy, MD,
Shaf Keshavjee, MD, MS*
Division of Thoracic Surgery, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
* Address correspondence to Dr Keshavjee, Division of Thoracic Surgery, Toronto General Hospital, 200 Elizabeth St, 9N-950, Toronto, Ontario, M5G 2C4 Canada (Email: shaf.keshavjee{at}uhn.on.ca).
A 25-year-old woman had been having occasional episodes of headache, dizziness, palpitations, and excessive sweating for the prior 2 years. These were triggered by emotional stress and would last 2 to 3 hours and subside spontaneously. Last year she was about to undergo breast reduction surgery when she had a severe hypertensive episode with the induction of general anesthesia. The surgery was aborted and she was worked up for a possible pheochromocytoma.
Her 24-hour urine norepinephrine and vanillylmandelic acid levels were elevated, but a computed tomographic scan of the abdomen did not demonstrate any adrenal or other masses. An 131I-metaiodobenzylguanidine scan showed uptake at the right hilum of the chest, and subsequent chest computed tomographic and magnetic resonance imaging scans showed a solid, well-circumscribed right mediastinal mass that was 3 cm in diameter, inferior to the right main pulmonary artery, adjacent to the right atrium, and sitting between the superior and inferior pulmonary veins.
Figure 1
shows the tumor (arrow) on an unenhanced magnetic resonance image of the coronal section.
Figures 2 and 3
show significant highlighting on the T1-weighted gadolinium-enhanced coronal and axial cuts, confirming this to be extrapericardial, which was unusual for a middle mediastinal pheochromocytoma. The mediastinal tumor is shown by the arrow in both figures.
The patient was given 2 weeks of phenoxybenzamine until the morning of her surgery, and was admitted the day before for hydration. At thoracotomy, the tumor was located between the inferior and superior pulmonary veins with splaying of the superior pulmonary vein branches. The tumor was inferior and separate from the right main pulmonary artery, but it was adherent to the middle lobe branches of the pulmonary artery so that the tumor was excised en bloc with the right middle lobe. The intraoperative course was unremarkable except for a brief period of hypertension when the tumor was initially dissected, and mild hypotension when the feeding blood supply of the tumor was divided. Postoperatively, hydration was continued and she was discharged after 2 days.
A subsequent 131I-metaiodobenzylguanidine scan showed no residual uptake; however, the pathology was suggestive of an aggressive paraganglioma invading adjacent tissues, and she was referred for consideration of adjuvant external beam radiotherapy.
