On-pump beating resection of cardiac pheochromocytoma

Abstract

We describe the case of 34-year-old woman with a cardiac pheochromocytoma that was diagnosed by scintigraphy using iodine-131 metaiodobenzylguanidine. For preoperative evaluation, we chose multidetector computed tomography instead of coronary angiography, for fear that catheter manipulation might trigger catecholamine release from the tumor; it showed that no major coronary artery branches run through the tumor. The tumor resection was carried out safely with the use of cardiopulmonary bypass and without cardiac arrest.

Keywords

Cardiopulmonary bypass catecholamines heart neoplasms multidetector computed tomography pheochromocytoma

Case report

A 34-year-old woman presented to her physician with a one-year history of paroxysmal headache and palpitations. Her past history was unremarkable, and she had no family history. Twenty-four-hour sphygmomanometry revealed paroxysmal hypertension, and she has elevated plasma norepinephrine, urinary norepinephrine, and dopamine levels, but normal plasma and urinary epinephrine levels. Pheochromocytoma was suspected, and iodine-131 labeled metaiodobenzylguanidine scintigraphy revealed positive uptake in the hilum of the left lung, but not in the adrenal glands. Computed tomography (CT) showed a single mass between the left atrium and the main pulmonary artery, and transesophageal echocardiography revealed a hypoechoic mass in the pericardial cavity. On the basis of these findings, the patient was diagnosed with cardiac pheochromocytoma. She was started on an alpha blocker and referred to our hospital for surgical treatment. Multidetector CT showed an intimate anatomical relationship between the tumor and the left coronary artery. The tumor was located very close to the left coronary artery, but no major arterial supply from the coronary artery was seen (Figure 1). Surgery was performed through a median sternotomy. After opening the pericardium, the tumor was found beside the left atrial appendage, extending from the surface of the main pulmonary artery to the proximal portion of the left anterior descending artery (Figure 2). Cardiopulmonary bypass was established with aortic and bicaval cannulation. The tumor was covered with a thin capsule, and was removed without cardiac arrest. Small vessels feeding the tumor were ligated with hemoclips, and the tumor was resected as a single mass with adequate margins. No reconstruction was needed. The patient was hemodynamically stable under cardiopulmonary bypass, although her heart rate increased when the tumor was palpated. The patient’s postoperative course was uneventful, and her serum and urinary catecholamine levels were normalized (Table 1). No recurrence has been observed so far. The pathological report showed that the tumor consisted of neuroendocrine cells, characteristic of pheochromocytoma (Figure 3).

Figure 1.

Multidetector computed tomography revealed the relationship between the coronary artery and the tumor. Although the tumor was located on the left anterior descending artery, no major coronary artery branches, such as the diagonal branch, ran through it.

Figure 2.

Picture taken from surgeon’s view. Cranial is to the left of the image. The tumor was covered with a thin capsule and located between the left atrium and the main pulmonary artery. The border between the tumor and surrounding cardiac structures was clear.

Figure 3.

Immunohistochemical staining showing cells positive for synaptophysin and chromogranin A. Synaptophysin is a maker of neuroendocrine tumors, and chromogranin is found in chromaffin cells and elevated in pheochromocytoma.

Table 1.

Plasma and urinary catecholamine levels before and after resection of pheochromocytoma.

Variable	Before	After	Normal range
Plasma catecholamines
Epinephrine (pg·mL⁻¹)	8	10	<100
Norepinephrine (pg·mL⁻¹)	1582	132	100–450
Dopamine (pg·mL⁻¹)	12	9	<20
Urine catecholamines
Epinephrine (µg·day⁻¹)	6.4	7.2	3.4–26.9
Norepinephrine (µg·day⁻¹)	308.4	99.4	48.6–168.4
Dopamine (µg·day⁻¹)	2166.0	610.9	365.0–961.5

Discussion

The incidence of ectopic pheochromocytoma is approximately 10% of all cases, and less than 2% are found in the chest, usually in the posterior mediastinum.¹ The diagnosis is confirmed by elevated blood and urine levels of catecholamines and their metabolites. Imaging studies for evaluation of ectopic pheochromocytoma include CT, magnetic resonance imaging, and a functional imaging study such as metaiodobenzylguanidine scintigraphy. Coronary angiography may be valuable for identifying the relationship between the feeding artery and the coronary artery. Multidetector CT is also a good tool for evaluating the coronary artery; it is superior to coronary angiography in that it does not carry the risk of catecholamine release from the tumor, which may be triggered by catheter manipulation, and it can show 3-dimensional relationships between the tumor and surrounding tissue, especially the coronary arteries. For these reasons, multidetector CT was chosen instead of coronary angiography for preoperative evaluation in this case, and sufficient information was obtained to perform the operation safely.

Surgical excision of the tumor usually results in permanent cure and relief of symptoms. Some cases may require extensive cardiac reconstruction, such as coronary artery bypass grafting.² Cardiopulmonary bypass with cardioplegic arrest is recommended for the surgical resection of cardiac pheochromocytoma, but on-pump beating resection was a good strategy in this case because the coronary artery and tumor vessels could be easily identified. If the patient becomes hemodynamically unstable during the operation, it is easy to convert on-pump beating to on-pump arrest resection. Moreover, it does not carry the risk of sudden catecholamine release from the tumor when the aorta is declamped. In addition to these advantages, we did not arrest cardiac circulation because the tumor did not invade the cardiac structures, the margin was clear, and the patient remained hemodynamically stable during the procedure.

We recommend on-pump beating tumor resection if there is no tumor invasion, and cardiopulmonary bypass with cardioplegic arrest in other cases, to control severe arrhythmias and hemorrhage, and allow for concomitant reconstructive surgery if needed.³

Footnotes

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conflicts of interest statement

None declared.

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