New therapeutic and surgical approaches for sporadic and hereditary pheochromocytoma

Successful management of unsuspected retroperitoneal paraganglioma via the use of combined epidural and general anesthesia: a case report

Introduction

Similar to pheochromocytomas, paragangliomas can secrete catecholamines, although they are usually non-functional and clinical presentation is non-specific. We present a case of accidental, intra-operatively diagnosed neuroendocrine-active sympathetic paraganglioma, which was suspected and confirmed during elective retroperitoneal tumor removal.

Case presentation

A 25-year-old Caucasian Croatian man, American Society of Anesthesiologists status 1, underwent elective surgery for retroperitoneal tumor removal. The tumor had been discovered by chance during a routine examination and was suspected to be a sarcoma. Our patient had no history of previous medical conditions nor did he have symptoms characteristic of a neuroendocrine secreting tumor. The results of ultrasound and magnetic resonance imaging studies showed a large, well demarcated retroperitoneal tumor mass in his upper abdomen localized between the aorta and vena cava, measuring approximately 9×6×4.5cm. In the operating room an epidural catheter was inserted at the T7 to T8 level prior to induction of general anesthesia. Epidural analgesia was maintained by an infusion pump with local anesthetic and opiate mixture. During the surgical excision of the tumor, hemodynamic changes occurred, with hypertension (205/110mmHg) and tachycardia (up to 120 beats/minute). In spite of the fact that the surgical field of work did not include adrenal glands whose direct manipulation could explain this occurrence, there was a high degree of suspicion for the presence of a neurosecreting tumor. His clinical symptoms were relieved after administration of urapidil, esmolol and magnesium sulfate. After tumor excision, our patient developed severe hypotension. Hemodynamic stability was reinstated with aggressive volume replacement, with crystalloids and colloids, vasopressors and hydrocortisone. His post-operative course was unremarkable and on the eighth post-operative day our patient was discharged from hospital, with no consequences or symptoms on follow-up two years after surgery.

Conclusions

Our patient’s case emphasizes the need to consider the presence of extra-adrenal paragangliomas in the differential diagnosis of retroperitoneal tumors, despite their rare occurrence. In our patient’s case, invasive hemodynamic monitoring during combined general anesthesia and epidural analgesia and early recognition of catechol-induced symptoms raised suspicion of the existence of a paraganglioma, and this led to an adequate therapeutic approach and favorable outcome of the surgery. Pre-operative recognition of paragangliomas could lead to better pre-operative preparation, but even high clinical suspicion in undiagnosed forms during surgery and the availability of rapid and short-acting vasodilatators, α-blockers and β-blockers might favor good outcome.

Pheochromocytomas and secreting paragangliomas

Catecholamine-producing tumors may arise in the adrenal medulla (pheochromocytomas) or in extraadrenal chromaffin cells (secreting paragangliomas). Their prevalence is about 0.1% in patients with hypertension and 4% in patients with a fortuitously discovered adrenal mass. An increase in the production of catecholamines causes symptoms (mainly headaches, palpitations and excess sweating) and signs (mainly hypertension, weight loss and diabetes) reflecting the effects of epinephrine and norepinephrine on α- and β-adrenergic receptors. Catecholamine-producing tumors mimic paroxysmal conditions with hypertension and/or cardiac rhythm disorders, including panic attacks, in which sympathetic activation linked to anxiety reproduces the same signs and symptoms. These tumors may be sporadic or part of any of several genetic diseases: familial pheochromocytoma-paraganglioma syndromes, multiple endocrine neoplasia type 2, neurofibromatosis 1 and von Hippel-Lindau disease. Familial cases are diagnosed earlier and are more frequently bilateral and recurring than sporadic cases. The most specific and sensitive diagnostic test for the tumor is the determination of plasma or urinary metanephrines. The tumor can be located by computed tomography, magnetic resonance imaging and metaiodobenzylguanidine scintigraphy. Treatment requires resection of the tumor, generally by laparoscopic surgery. About 10% of tumors are malignant either at first operation or during follow-up, malignancy being diagnosed by the presence of lymph node, visceral or bone metastases. Recurrences and malignancy are more frequent in cases with large or extraadrenal tumors. Patients, especially those with familial or extraadrenal tumors, should be followed-up indefinitely.

Biochemical diagnosis, localization and management of pheochromocytoma: focus on multiple endocrine neoplasia type 2 in relation to other hereditary syndromes and sporadic forms of the tumour

Approximately 50% of patients with multiple endocrine neoplasia (MEN) 2A or 2B develop pheochromocytoma. These tumours are almost exclusively benign and localized in the adrenal glands. About one-third are bilateral at initial diagnosis. Amongst patients with pheochromocytoma, those with MEN 2A have subtler symptoms compared to those with sporadic disease. Since pheochromocytomas in patients with MEN 2 often secrete catecholamines episodically (but metabolize them continuously to metanephrines), the first choice for biochemical diagnosis is the measurement of free metanephrines in plasma, with urinary fractionated metanephrines being the second choice. In patients with pheochromocytomas that produce exclusively normetanephrine, MEN 2 can be excluded. In patients with biochemically proven MEN 2-related pheochromocytoma, anatomical imaging of the adrenals (with either computerized tomography or magnetic resonance) should be obtained next. Functional imaging with specific ligands (e.g. scintigraphy with [(123)I]-metaiodobenzylguanidine or, if available, positron emission tomography with [(18)F]-fluorodopamine, [(18)F]-dihydroxyphenylalanine, [(11)C]-adrenaline or [(11)C]-hydroxyephedrine) may then be particularly useful in patients with distorted anatomy from previous surgery, in cases of equivocal biochemical data despite high clinical suspicion for a tumour, to rule out multifocal disease, or where there is suspicion of metastatic disease (e.g. tumours larger than 5 cm). Laparoscopic surgery is the treatment of choice and subtotal (cortical-sparing) adrenalectomy is the procedure of choice in bilateral pheochromocytomas.

Surgical management of hereditary pheochromocytoma1 1No competing interests declared

BACKGROUND

Surgical treatment of hereditary pheochromocytoma remains controversial because of the need for lifelong corticosteroid therapy and the risk of Addisonian crisis associated with bilateral total adrenalectomy. We examined our large series of patients with hereditary pheochromocytoma to evaluate postsurgical outcomes, particularly in those who underwent cortical-sparing adrenalectomy.

STUDY DESIGN

We retrospectively reviewed the outcomes of all patients with histopathologic diagnoses of hereditary pheochromocytoma treated at our institution from 1962 to 2003. Familial disease was initially determined by pedigree analysis, genetic testing, or both for multiple endocrine neoplasia (MEN) types 1, 2A, or 2B; von Hippel-Lindau disease (VHL); neurofibromatosis type 1 (NF-1); or familial paraganglioma syndrome (FP).

RESULTS

Adrenal pheochromocytomas were present in 56 of 59 patients (95%): MEN2A (39), MEN2B (7), VHL (6), MEN1 (2), NF-1 (2). Paragangliomas (extraadrenal pheochromocytomas) were present in the remaining 3 of 59 patients (5%): FP (2) and NF-1 (1). Thirty-eight of 56 patients with pheochromocytomas had cumulative operations resulting in total or subtotal bilateral adrenalectomy. Acute adrenal insufficiency (Addisonian crisis) occurred in 4 of these 38 patients (11%). Cortical-sparing adrenalectomy was performed in 26 patients who underwent bilateral adrenal resection; 17 (65%) were corticosteroid independent at a median followup of 71 months. Recurrent pheochromocytoma developed in an adrenal remnant in 3 of 30 patients (10%) who underwent unilateral or bilateral cortical-sparing procedures. Metastatic disease did not develop in any patient with pheochromocytoma, but has occurred in two of three patients with paragangliomas.

CONCLUSIONS

Our data suggest that a cortical-sparing adrenalectomy can successfully avoid the need for corticosteroid replacement in the majority of patients who undergo a bilateral adrenalectomy. Long-term followup should include monitoring of the remnant gland for recurrent pheochromocytoma with yearly biochemical screening studies.

Hypertension and adrenal disorders

Adrenal disorders causing hypertension can be related to the dysfunction of either the adrenal cortex or the adrenal medulla. These disorders, including congenital adrenal hyperplasia (CAH), owing to 11B-hydroxylase deficiency and to 17alpha-hydroxylase deficiency; apparent mineralocorticoid excess; familial hyperaldosteronism type I; primary aldosteronism; Cushing's syndrome; and familial glucocorticoid resistance, primarily affect the adrenal cortex and cause low-renin hypertension. The classic disorder of the adrenal medulla resulting in hypertension is pheochromocytoma, although hypertension in obesity might also be associated with catecholamine secretion. In this review, we discuss these etiologies and the most recent advances in our knowledge of their pathophysiology, diagnosis, and treatment.