Pheochromocytoma with Steady Low Secretory Activity, Can We Observe?

Presentation Number: SAT 395
Date of Presentation: April 1st, 2017

Amer Issa* and Wael Taha
Wayne State University, Detroit, MI

Abstract

Background:

Pheochromocytoma can cause hypertension and other non-specific symptoms. The associated clinical picture depends on the amount and pattern of catecholamine release. Most pheochromocytomas present as adrenal incidentalomas with biochemical evidence of catecholamine excess. The typical management of these tumors has been surgical resection.

We present a case of pheochromocytoma with low secretory activity in a hypertensive elderly patient in whom surgical resection of the tumor did not have any clinical impact on patient’s symptoms or hypertension.

Clinical case:

A 73-year-old African American male was referred to the endocrinology clinic for evaluation of a 3.2 cm left adrenal incidentaloma. He did not have any complaints of episodic headaches, palpitations, sweating or chest pain. He had hypertension for 10 years, which was well controlled on Lisinopril 10 mg daily, Carvedilol 6.25 mg twice daily and Amlodipine 10 mg daily. There was no history of weight gain, excess hair growth, acne or proximal muscle weakness.

On examination, pulse was 81 beats/min and blood pressure was 109/74 mmHg. The rest of his physical examination was unremarkable.

MRI showed a 3.2 cm lipid poor, left adrenal mass.

Biochemical tests showed: plasma aldosterone (15.4 ng/dl), plasma renin (0.4 ng/ml/hr), aldosterone/renin ratio (38.5), DHEA-S (77 ug/dl, n 28-175 ug/dl), low-dose dexamethasone suppression test (cortisol after 1 mg dexamethasone 1.9 ug/dl), plasma metanephrine (0.24 nmol/l, n <0.49 nmol/l), plasma normetanephrine (5.3 nmol/l, n <0.89 nmol/l), 24-hour urinary metanephrine (218 ug/d, n 30-350 ug/d) and 24-hour urinary normetanephrine (1780 ug/d, n 50-650 ug/d).

Further testing showed: plasma aldosterone (13.4 ng/dl), plasma renin (0.4 ng/ml/hr), aldosterone/renin ratio (33.5), saline infusion test (aldosterone level after infusion of 2 liters of 0.9% saline IV over 4 hours was 5.6 ng/dl), late night salivary cortisol (0.134 ug/dl, n < 0.228 ug/dl), plasma metanephrine (0.15 nmol/l, n <0.49 nmol/l), plasma normetanephrine (3.56 nmol/l, n <0.89 nmol/l). Repeated plasma normetanephrine level at different occasions was (3.42, 3.51 nmol/l).

Although being asymptomatic, patient elected to proceed with surgery. He was prescribed doxazosin 2 mg and carvedilol 12.5 mg twice a day prior to the surgery. He underwent left adrenalectomy with no complications. Surgical pathology showed pheochromocytoma.

After surgery, he continued to require carvedilol 6.25 mg twice daily, amlodipine 10 mg and lisinopril 10 mg daily to control his blood pressure. Biochemical testing after surgery showed: plasma normetanephrine (0.99 nmol/l, nl <0.89 nmol/l).

Conclusion:

Pheochromocytoma with steady low catecholamine release may not be the cause of hypertension. Close monitoring of such cases with controlled hypertension might be an alternative option to surgery in otherwise asymptomatic patients.

 

Nothing to Disclose: AI, WT