Pheochromocytoma

The following common presenting signs and symptoms are seen in patients diagnosed with pheochromocytoma:

• Elevated blood pressure
• Severe headache
• Tremors
• Tachypnea 
• Pallor of the face
• Tachycardia and distinct heart sounds
• Diaphoresis (excessive sweating)
• Anxiety 
• Abdominal discomfort or pain
• Constipation 
• Weight loss

The following diagnostic modalities and test are conducted on a patient suspected to have pheochromocytoma:

• Epinephrine and norepinephrine assays: Blood samples or a 24 hour urine sample may be collected to determine and measure the serum catecholamine concentration.
• Suppression testing: This medical test makes use of clonidine or phentolamine to suppress the effects of systemic epinephrine and norepinephrine in pheochromocytoma. 
• Computed tomography (CT scan): This imaging tests that will elucidate the adrenal tumor in the abdomen. It may show size, location, and the number of adrenal tumors. 
• Magnetic resonance imaging (MRI): This imaging modality is used demonstrate a more detailed view of the adrenal tumor above the kidneys intraabdominally.
• M-Iodobenzylguanidine (MIBG) imaging: This is a radio-imaging technology that detects tumors that absorbs the radioactive iodine and dye injected in the circulatory system.
• Positron emission tomography (PET): PET is used to detect the uptake of radioactive substances in active abdominal tumors.

The primary approach in the treatment of pheochromocytoma is by means of surgical removal which can be performed using a minimally invasive abdominal laparotomy or laparoscopic adrenalectomy. This procedure is most beneficial for patients having adrenal tumor which is no bigger than 8 centimeters in length. The patient’s hypertensive crisis prior to surgery is stabilized using alpha-blockers and beta-blockers to inhibit the systemic effects of epinephrine and norepinephrine [10]. Stress doses of steroids may be given if bilateral adrenalectomy is being contemplated preoperatively. Malignant pheochromocytomas are treated using radionuclide therapy, chemotherapy, and targeted cancer therapies.

Patients suffering from malignant pheochromocytoma have a 5-year survival rate of less than 50% in most cases. However, non-malignant pheochromocytoma will have more than 95% chance of survival within the next 5 years from diagnosis. The adrenal tumor has a 10% chance of malignant degeneration. They prompt surgical removal of the tumor (unilateral or bilateral adrenalectomy) usually results to a complete cure.

Uncontrolled pheochromocytoma may complicate to myocardial infarction, myocarditis, dilated cardiomyopathy, intracerebral hemorrhage, and pulmonary edema. Pheochromocytoma tumor occurs rarely in pregnancy with an incidence rate of 2 cases per 100,000 pregnancies. The coexistence of the adrenal tumor with pregnancy carries a grim prognosis for both mother and child [9].

The occurrence of pheochromocytoma is generally sporadic, although 30% of the cases are linked to genetic mutations. There are at least 10 genes that are already identified that may phenotypically express as paraganglioma (extrarenal pheochromocytoma) or intraabdominal pheochromocytoma [3]. Patients diagnosed with multiple endocrine neoplasia (MEN) usually present with pheochromocytoma, a gross incidence rate of 19% of patients positively diagnosed with pheochromocytoma are associated with a concomitant MEN syndrome or Von Hippel-Landau (VHL) disease.

Globally, pheochromocytoma is relatively rare and are often times underdiagnosed. Pheochromocytoma tumors occurs in just 5 to 20 patients per 10,000 diagnosed hypertensive patients. A prospective study conducted in Mayo Clinic reveals that at least 50% of the diagnosed cases of pheochromocytoma were made during autopsy [4]. In the clinics, pheochromocytoma is usually an incidental finding during imaging studies in 10% of cases [5].

The main pathophysiology of pheochromocytoma is brought about by the oversecretion of the catecholamine hormones like norepinephrine and epinephrine from the chromaffin cells of the adrenal medulla [6]. The secreted catecholamine hormones consequentially stimulate the alpha adrenergic receptors which results in hypertension, increased cardiac contractility, increased in heart rate, intestinal relaxation, breakdown of glycogen, and gluconeogenesis [7].

The secretion of the catecholamine from the tumor remains unregulated and it is not influenced by any nerve or neural stimulation. Life-threatening hypertensive crisis in pheochromocytoma may be precipitated by anesthesia induction, intake of opiates, use of metoclopramide, tricyclic antidepressant maintenance, childbirth, and intake of beta-blockers [8].

Pheochromocytoma has a rare occurrence and is usually difficult to diagnose; thus, proactive prevention may prove to be most difficult. Genetic counseling among afflicted patients may reduce the recurrence of the disease among the offspring. The prompt diagnosis and treatment of the adrenal tumor prevents life-threatening complications.

Pheochromocytoma is a rare, often benign tumor that usually develops in the adrenal medulla. The adrenal tumor releases catecholamine hormones that induce cardiac arrhythmias and high blood pressure [1]. Pheochromocytoma can cause other serious complications in different organ systems especially in the cardiovascular system [2]. The surgical removal of the pheochromocytoma tumor of the adrenal gland or adrenalectomy consequently reverts all symptoms to normal.

Definition

Pheochromocytoma is a rare, often benign tumor that usually develops in the adrenal medulla producing excessive amounts of catecholamines like epinephrine and norepinephrine.

Cause

The etiology of pheochromocytoma is usually sporadic but is sometimes linked to genetic mutations and heredity. The tumor may occur along with MEN and VHL disease.

Symptoms

Patients presenting with pheochromocytoma usually come in with high blood pressure, diaphoresis, pallor, tachycardia, tachypnea, and severe headache.

Diagnosis

The diagnosis of pheochromocytoma relies on the demonstration of the catecholamines and derivatives in the patient’s blood and urine. Imaging studies like CT scan, MRI, MIBG, and PET are implored to elucidate the adrenal tumor.

Treatment and follow-up

The primary goal in the treatment of pheochromocytoma is the surgical removal of the tumor through surgical laparotomy or laparoscopic adrenalectomy. Stress doses of corticosteroids are given preoperatively when bilateral adrenalectomy is planned. Antihypertensive medications are given to stabilize the blood pressure preoperatively. Chemotherapy and radionuclide therapy are used to treat malignant adrenal cell tumors.

1. Prejbisz A, Lenders JW, Eisenhofer G, Januszewicz A. Cardiovascular manifestations of phaeochromocytoma. J Hypertens. Nov 2011; 29(11):2049-60.
2. Waguespack SG, Rich T, Grubbs E, Ying AK, Perrier ND, Ayala-Ramirez M, et al. A current review of the etiology, diagnosis, and treatment of pediatric pheochromocytoma and paraganglioma. J Clin Endocrinol Metab. May 2010; 95(5):2023-37.
3. Därr R, Lenders JWM, Hofbauer LC, Naumann B, Bornstein SR, Eisenhofer G. Pheochromocytoma: Update on Disease Management. Ther Adv in Endo and Metab. 2012; 3(1):11-26.
4. Beard CM, Sheps SG, Kurland LT, Carney JA, Lie JT. Occurrence of pheochromocytoma in Rochester, Minnesota, 1950 through 1979. Mayo Clin Proc. Dec 1983; 58(12):802-4.
5. Young WF Jr. Clinical practice. The incidentally discovered adrenal mass. N Engl J Med. Feb 8 2007; 356(6):601-10.
6. Eisenhofer G, Pacak K, Huynh TT, Qin N, Bratslavsky G, Linehan WM, et al. Catecholamine metabolomic and secretory phenotypes in phaeochromocytoma. Endocr Relat Cancer. Feb 2011; 18(1):97-111.
7. Elenkova A, Matrozova J, Zacharieva S, Kirilov G, Kalinov K. Adiponectin - A possible factor in the pathogenesis of carbohydrate metabolism disturbances in patients with pheochromocytoma. Cytokine. Jun 2010; 50(3):306-10.
8. Rivers G, Rosas AL, Quezado Z, Manger WM, Eisenhofer G, Pacak K. Adverse drug reactions in patients with phaeochromocytoma: incidence, prevention and management. Drug Saf. 2007; 30(11):1031-62.
9. Lenders JW. Pheochromocytoma and pregnancy: a deceptive connection.Eur J Endocrinol. 2012 Feb; 166(2):143-50. Epub 2011 Sep 2.
10. Wong C, Yu R. Preoperative preparation for pheochromocytoma resection: physician survey and clinical practice. Exp Clin Endocrinol Diabetes. Jul 2010; 118(7):400-4. 

• Pheochromocytoma
  User61944, 2019-06-23 21:39