pheochromocytoma


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Pheochromocytoma

 

Definition

Pheochromocytoma is a tumor of special cells (called chromaffin cells), most often found in the middle of the adrenal gland.

Description

Because pheochromocytomas arise from chromaffin cells, they are occasionally called chromaffin tumors. Most (90%) are benign tumors so they do not spread to other parts of the body. However, these tumors can cause many problems and if they are not treated and can result in death.
Pheochromocytomas can be found anywhere chromaffin cells are found. They may be found in the heart and in the area around the bladder, but most (90%) are found in the adrenal glands. Every individual has two adrenal glands that are located above the kidneys in the back of the abdomen. Each adrenal gland is made up of two parts: the outer part (called the adrenal cortex) and the inner part (called the adrenal medulla). Pheochromocytomas are found in the adrenal medulla. The adrenal medulla normally secretes two substances, or hormones, called norepinephrine and epinephrine. These two substances, when considered together, are known as adrenaline. Adrenaline is released from the adrenal gland, enters the bloodstream and helps to regulate many things in the body including blood pressure and heart rate. Pheochromocytomas cause the adrenal medulla to secrete too much adrenaline, which in turn causes high blood pressure. The high blood pressure usually causes the other symptoms of the disease.
Pheochromocytomas are rare tumors. They have been reported in babies as young as five days old as well as adults 92 years old. Although they can be found at any time during life, they usually occur in adults between 30 and 40 years of age. Pheochromocytomas are somewhat more common in women than in men.

Causes and symptoms

The cause of most pheochromocytomas is not known. A small minority (about 10-20%) of pheochromocytomas arise because a person has an inherited susceptibility to them. Inherited pheochromocytomas are associated with four separate syndromes: Multiple Endocrine Neoplasia, type 2A (MEN2A), Multiple Endocrine Neoplasia, type 2B (MEN2B), von Hippel-Lindau disease (VHL) and Neurofibromatosis type 1 (NF1).
Individuals with pheochromocytomas as part of any of these four syndromes usually have other medical conditions as well. People with MEN2A often have cancer (usually thyroid cancer) and other hormonal problems. Individuals with MEN2B can also have cancer and hormonal problems, but also have other abnormal physical features. Both MEN2A and MEN2B are due to genetic alterations or mutations in a gene called RET, found at chromosome 10q11.2. Individuals with VHL often have other benign tumors of the central nervous system and pancreas, and can sometimes have renal cell cancer. This syndrome is caused by a mutation in the VHL gene, found at chromosome 3p25-26. Individuals with NF1 often have neurofibromas (benign tumors of the peripheral nervous system). NF1 is caused by mutations in the NF1 gene, found at chromosome 17q11.
All of these disorders are inherited in an autosomal dominant inheritance pattern. With autosomal dominant inheritance, men and women are equally likely to inherit the syndrome. In addition, children of individuals with the disease are at 50% risk of inheriting it. Genetic testing is available for these four syndromes (MEN2A, MEN2B, VHL and NF1) but, due to the complexity, genetic counseling should be considered before testing.
Most people (90%) with pheochromocytoma have hypertension, or high blood pressure. The other symptoms of the disease are extremely variable. These symptoms usually occur in episodes (or attacks) called paroxysms and include:
  • headaches
  • excess sweating
  • racing heart
  • rapid breathing
  • anxiety/nervousness
  • nervous shaking
  • pain in the lower chest or upper abdomen
  • nausea
  • heat intolerance
The episodes can occur as often as 25 times a day or, as infrequently as once every few months. They can last a few minutes, several hours, or days. Usually, the attacks occur several times a week and last for about 15 minutes. After the episode is over, the person feels exhausted and fatigued.
Between the attacks, people with pheochromocytoma can experience the following:
  • increased sweating
  • cold hands and feet
  • weight loss
  • constipation

Diagnosis

If a pheochromocytoma is suspected, urine and/or a blood test are usually recommended. A test called "24-hour urinary catacholamines and metanephrines" will be done. This test is designed to look for adrenaline and the break-down products of adrenaline. Since the body gets rid of these hormones in the urine, those testing will need to collect their urine for 24 hours. The laboratory will determine whether or not the levels of hormones are too high. This test is very good at making the diagnosis of pheochromocytoma. Another test called "serum catacholamines" measures the level of adrenaline compounds in the blood. It is not as sensitive as the 24-hour urine test, but can still provide some key information if it shows that the level of adrenaline compounds is too high.
One of the difficulties with these tests is that a person needs to have an attack of symptoms either during the 24-hour urine collection time period or shortly before the blood is drawn for a serum test to ensure the test's accuracy. If a person did not have an episode during that time, the test can be a "false negative". If a doctor suspects the patient has had a "false negative" test, additional tests called "pharmacologic tests" can be ordered. During these tests, a specific drug is given to the patient (usually through an IV) and the levels of hormones are monitored from the patient's blood. These types of tests are only done rarely.
Once a person has been diagnosed with a pheochromocytoma, he or she will undergo tests to identify exactly where in the body the tumor is located. The imaging techniques used are usually computed tomography scan (CT scan) and magnetic resonsance imaging (MRI). A CT scan creates pictures of the interior of the body from computer-analyzed differences in x rays passing through the body. CT scans are performed at a hospital or clinic and take only a few minutes. An MRI is a computerized scanning method that creates pictures of the interior of the body using radio waves and a magnet. An MRI is usually performed at a hospital and takes about 30 minutes.

Treatment

Once a pheochromocytoma is found, more tests will be done to see if the tumor is benign (not cancer) or malignant (cancer). If the tumor is malignant, tests will be done to see how far the cancer has spread. There is no accepted staging system for pheochromocytoma; but an observation of the tumor could provide one of these four indications:
  • Localized benign pheochromocytoma means that the tumor is found only in one area, is not cancer, and cannot spread to other tissues of the body.
  • Regional pheochromocytoma means that the tumor is malignant and has spread to the lymph nodes around the original cancer. Lymph nodes are small structures found all over the body that make and store infection-fighting cells.
  • Metastatic pheochromocytoma means that the tumor is malignant and has spread to other, more distant parts of the body.
  • Recurrent pheochromocytoma means that a malignant tumor that was removed has come back.
Treatment in all cases begins with surgical removal of the tumor. Before surgery, medications such as alpha-adrenergic blockers are given to block the effect of the hormones and normalize blood pressure. These medications are usually started seven to 10 days prior to surgery. The surgery of choice is laparoscopic laparotomy, which is a minimally invasive outpatient procedure performed under general or local anesthesia. A small incision is made in the abdomen, the laparoscope is inserted, and the tumor is removed. The patient can usually return to normal activities within two weeks. If a laparoscopic laparotomy cannot be done, a traditional laparotomy will be performed. This is a more invasive surgery done under spinal or general anesthesia and requires five to seven days in the hospital. Usually patients are able to return to normal activities after four weeks. After surgery, blood and urine tests will be done to make sure hormone levels return to normal. If the hormone levels are still above normal, it may mean that some tumor tissue was not removed. If not all tumor can be removed (as in malignant pheochromocytoma, for example) drugs will be given to control high blood pressure.
If a pheochromocytoma is malignant, radiation therapy and/or chemotherapy may be used. Radiation therapy uses high-energy x rays to kill cancer cells and shrink tumors. Because there is no evidence that radiation therapy is effective in the treatment of malignant pheochromocytoma, it is not often used for treatment. However, it is useful in the treatment of painful bone metastases if the tumor has spread to the bones. Chemotherapy uses drugs to kill cancer cells. Like radiation therapy, it has not been shown to be effective in the treatment of malignant pheochromocytoma. Chemotherapy, therefore, is only used in rare instances.
Untreated pheochromocytoma can be fatal due to complications of the high blood pressure. In the vast majority of cases, when the tumor is surgically removed, pheochromocytoma is cured. In the minority of cases (10%) where pheochromocytoma is malignant, prognosis depends on how far the cancer has spread, and the patient's age and general health. The overall median five-year survival from the initial time of surgery and diagnosis is approximately 43%.

Prevention

Unfortunately, little is known about environmental and other causes of pheochromocytoma. Some of the tumors are due to inherited predisposition. Because of these factors, pheochromocytoma can not be prevented.

Resources

Books

Goldfien, Alan. "Adrenal Medulla." In Basic and Clinical Endocrinology, edited by Francis Greenspan and David Gardner. NewYork: Lange Medical Books/ McGraw-Hill, 2001, pp. 399-421.
Keiser, Harry R. "Pheochromocytoma and Related Tumors.". In Endocrinology, edited by Leslie J. DeGroot and J. LarryJameson, 4th ed. New York: W.B. Saunders Company, 2001, pp. 1862-1883.

Periodicals

Barzon, Luisa, and Marco Boscaro. "Diagnosis and Management of Adrenal Incidentalomas." The Journal of Urology 163 (February 2000): 398-407.
Young, William F. "Management Approaches to AdrenalIncidentaloma" Endocrinology and Metabolism Clinics of North America 29 (March 2000): 159-185.

Other

"Pheochromocytoma" National Cancer Institute Cancer Web June 29, 2001. 〈http://www.graylab.ac.uk/cancernet/202494.html〉.

Key terms

Adrenal medulla — The central core of the adrenal gland.
Laparoscope — An instrument used to examine body cavities during certain types of surgery; for example, surgeries to remove fibroid tumors, or gall bladders, are often removed through the navel rather than cutting into the body.
Paroxysm — A sudden attack of symptoms.

pheochromocytoma

 [fe″o-kro″mo-si″to´mah]
a small chromaffin cell tumor, usually in the adrenal medulla but occasionally in chromaffin tissue of the sympathetic paraganglia. It is relatively rare and tends to occur in families. It can be cured if diagnosed early, but can be fatal once it causes irreparable damage to the cardiovascular system.
Symptoms. Because it is composed of cells similar to the secreting cells of the adrenal medulla, it often secretes epinephrine and norepinephrine, so that the cardinal symptom is hypertension. In some cases the blood pressure is consistently high with slight fluctuations, and in others it is intermittently high with normal periods. Other symptoms include severe headache, sweating, visual blurring, apprehension, tachycardia, and postural hypotension.
Diagnosis. Pheochromocytoma must be differentiated from several other disorders that it closely resembles, such as essential hypertension and thyrotoxicosis. Studies have shown that over 20 per cent of patients with this condition are carriers of associated familial disorders, such as cerebellar hemangioblastoma, sturge-weber syndrome, tuberous sclerosis, or von hippel-lindau disease. Diagnosis is based on the patient's symptoms and the findings of specific chemical and pharmacologic tests. A test involving measurement of vanillylmandelic acid, metanephrine, and normetanephrine in urine is most commonly used. The level of these substances in the urine of patients with pheochromocytoma is almost twice the upper limits of normal.
Treatment. Surgical removal of the tumor or tumors is necessary for complete remission of symptoms. There are two possible sets of complications of surgery: (1) a sudden rise in blood pressure with development of tachycardia due to discharge of pressor substances as the tumor is being manipulated; and (2) severe hypotension and shock following removal of the tumor. These hazards can be substantially reduced by the preoperative administration of sedatives and antihypertensive agents, and the use of blood or plasma to maintain adequate blood volume. If surgery has involved resection of a portion of the adrenal cortex, it may be necessary for the patient to receive adrenocortical hormones by injection. With proper treatment, up to 90 per cent of patients are curable.
Patient Care. Once the diagnosis of pheochromocytoma has been established, the patient is prepared for surgery. The preoperative period may extend for several weeks while attempts are made to stabilize the blood pressure and hormonal imbalances. The patient should be kept in a quiet atmosphere and usually is given sedatives, such as phenobarbital, to promote rest. Blood pressure is taken at frequent intervals and recorded. These readings are used later as a basis for comparison during the postoperative period. They also alert the physician to extremes in blood pressure that are characteristic in this disorder.

A day or two before surgery the patient may be given repeated doses of phentolamine to block the vasoconstricting effects of epinephrine and norepinephrine. The blood pressure may be drastically affected and therefore must be monitored frequently for signs of instability and dangerous extremes.

Postoperatively the patient must again be watched for development of severe hypertension, which can lead to stroke syndrome, and for extreme hypotension with circulatory collapse and profound shock.

If the adrenal cortex has been resected during surgery, hormonal imbalances are likely to occur. These include hypoglycemia, addisonian crisis and extreme diuresis, and electrolyte and fluid imbalance. The hypoglycemia is most likely to occur in patients who have had symptoms of diabetes mellitus prior to surgery and is treated with infusions of glucose solution. Adrenocortical hormones may be administered intravenously. The patient's status is closely monitored so that disturbances in electrolyte and fluid balance, extremes in blood pressure, and disorders of metabolism can be recognized early and treated promptly.

phe·o·chro·mo·cy·to·ma

(fē'ō-krō'mō-sī-tō'mă), [MIM*171300]
A functional chromaffinoma, usually benign, derived from adrenal medullary tissue cells and characterized by the secretion of catecholamines, resulting in hypertension, which may be paroxysmal and associated with attacks of palpitation, headache, nausea, dyspnea, anxiety, pallor, and profuse sweating. Pheochromocytoma is often hereditary, not only in phacomatoses (for example, Hippel-Lindau disease, neurofibromatosis, and familial endocrine neoplasia), but also as an isolated defect [MIM*171300] as an autosomal dominant trait.
See also: paraganglioma.
[G. pheo + G. chrōm, color; -oma - tumor]

pheochromocytoma

/pheo·chro·mo·cy·to·ma/ (-kro″mah-si-to´mah) a tumor of chromaffin tissue of the adrenal medulla or sympathetic paraganglia; symptoms, notably hypertension, reflect the increased secretion of epinephrine and norepinephrine.

pheochromocytoma

(fē′ō-krō′mō-sī-tō′mə)
n. pl. pheochromocyto·mas or pheochromocyto·mata (-mə-tə)
A usually benign tumor of the adrenal medulla or the sympathetic nervous system in which the affected cells secrete increased amounts of epinephrine or norepinephrine.

pheochromocytoma

[fē′ōkrō′mōsītō′mə] pl. pheochromocytomas, pheochromocytomata
Etymology: Gk, phaios, dark, chroma, color, kytos, cell, oma, tumor
a vascular tumor of chromaffin tissue of the adrenal medulla or sympathetic paraganglia, characterized by hypersecretion of epinephrine and norepinephrine, causing persistent or intermittent hypertension. Typical signs include headache, flushing, palpitation, sweating, nervousness, hyperglycemia, nausea, vomiting, and syncope. Weight loss, myocarditis, cardiac arrhythmia, and heart failure may occur. The tumor occurs most commonly at 40 to 60 years of age, and only a small percentage of the lesions are malignant. The cause is unknown. The diagnosis may be established by laboratory assays showing increased catecholamines and their metabolites in urine and by pressor tests; intravenously injected histamine causes a sharp increase in blood pressure, and the administration of phentolamine produces a marked decrease. Surgical excision is the usual treatment; patients with nonresectable tumors may be treated with adrenergic blocking agents or with methyl tyrosine, a drug that reduces norepinephrine production. Also spelled phaeochromocytoma.
observations The most prominent sign is severe sustained or episodic hypertension. This is accompanied by a classic symptom triad of severe, pounding paroxysmal headache, palpitations, and profuse sweating. Visual disturbances, dilated pupils, lower extremity paresthesia, nausea and vomiting, dizziness, tremors, and tachycardia are also seen during paroxysm. An elevated plasma concentration of normetanephrine or metanephrine from a 24-hour urine collection is a 100% sensitive test for pheochromocytoma. A clonidine suppression test reveals persistent elevations in plasma norepinephrine. CT scans and MRIs are useful for tumor location. Complications that typically result from nontreatment or advanced disease include uncontrolled hypertension, diabetes, cardiomyopathy, cardiac arrhythmias, and heart failure.
interventions The primary treatment for pheochromocytoma is surgical removal of the tumor via laparoscopic adrenalectomy. Individuals are stabilized, starting about 2 weeks preoperatively, with a combination of sympathetic blocking agents and liberal salt and fluid intake. Preoperative palpation of the abdomen is contraindicated because it could cause sudden release of catecholamine and severe hypertension. Any persistent hypertension or postoperative hypertension after surgery is managed with conventional antihypertensive drug therapy. Individuals with nonresectable tumors are treated with alpha blockers or methyl tyrosine.
nursing considerations Careful monitoring of blood pressure is crucial in preoperative and postoperative periods to detect abrupt and severe fluctuations. Cardiac monitoring is done to detect cardiac complications, such as arrhythmia. Rest, nourishment, hydration, and emotional support are also needed. Nursing plays a crucial role in screening and case finding. Screening should be done for anyone who exhibits signs of malignant or paradoxical hypertension or displays a poor response to antihypertensive drug therapy. Individuals with neurofibromatosis are also at increased risk for pheochromocytoma.
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Pheochromocytoma

pheochromocytoma

10% tumor Endocrinology A benign paraganglioma of adrenal medulla; 10% are associated with systemic disease–eg, von Recklinghausen's disease, von Hippel-Lindau syndrome, Sturge-Weber disease, MEN IIa and IIb; pheochromocytomas may produce ACTH, calcitonin, VIP Clinical The pheochromocytoma triad–headaches, sweating attacks and tachycardia in a hypertensive Pt has a 94% specificity and 91% sensitivity for pheochromocytoma–absence of all triad Sx in a hypertensive Pt excludes pheochromocytoma; other Sx include anxiety, tremor, pallor, N&V, fatigue, chest or abdominal pain, weight loss Lab ↑ VMA, ↑ metanephrine, free catecholamines, MHPG, dopamine, HVA Diagnosis Specificity of imaging Abdominal ultrasonography 100%; abdominal CT 100%; abdominal MRI 97%; MIBG–metaiodobenzylguanidine scintigraphy 97% Specificity of lab urine Epinephrine 98%; norepinephrine 95%; VMA 91% Specificity of lab plasma Norepinephrine 97%; chromogranin A 95%; epinephrine 91%

phe·o·chro·mo·cy·to·ma

(fē'ō-krō'mō-sī-tō'mă)
A functional chromaffinoma, usually benign, derived from adrenal medullary tissue cells and characterized by the secretion of catecholamines, resulting in hypertension, which may be paroxysmal and associated with attacks of palpitation, headache, nausea, dyspnea, anxiety, pallor, and profuse sweating.
See also: paraganglioma
Synonym(s): phaeochromocytoma.
[G. pheo + G. chrōm, color; -oma - tumor]

phe·o·chro·mo·cy·to·ma

(fē'ō-krō'mō-sī-tō'mă) [MIM*171300]
A functional chromaffinoma characterized by secretion of catecholamines, resulting in hypertension.
Synonym(s): phaeochromocytoma.
[G. pheo + G. chrōm, color; -oma - tumor]

pheochromocytoma, (fē´ōkrō´mōsītō´mə),

n a vascular tumor of chromaffin tissue of the adrenal medulla or sympathetic paraganglia, characterized by hypersecretion of epinephrine and norepinephrine, causing persistent or intermittent hypertension.

pheochromocytoma, phaeochromocytoma

a small chromaffin cell tumor, usually located in the adrenal medulla but occasionally occurring in chromaffin tissue of the sympathetic paraganglia. It occurs most often in dogs and cattle; in bulls it develops concurrently with C-cell tumors of the thyroid gland. Functional tumors secrete catecholamines, causing arteriolar sclerosis and medial hyperplasia and clinical signs of hypertension: tachycardia, edema and cardiac hypertrophy.
References in periodicals archive ?
Pheochromocytoma is a rare and mostly benign tumor which arises from chromaffin cells with excessive catecholamine production and secretion.
Pheochromocytoma shows intense uptake of metaiodobenzylguanidine (miBG), thus allowing for detection of small lesions in atypical areas.
Prevalence of clinically unsuspected pheochromocytoma.
Rat pheochromocytoma (PC12) cells (Greene and Tischler 1976), obtained from ATCC (American Type Culture Collection, Manassas, VA, USA), were cultured as described previously [Dingemans et al.
Furthermore, any systemic disease precluding laparoscopic approach such as severe cardiac or respiratory disorders, uncorrected coagulopathy and cranial hypertension as well as symptomatic pheochromocytomas during pregnancy should be considered as contraindications for LA.
A recurrent, short-lasting headache has been linked with transient, paroxysmal elevations of blood pressure in patients without underlying causes of pheochromocytoma.
Kathryn Anne "Kate" Wilson of Eugene died June 24 of pheochromocytoma.
Azedra is already being evaluated in an ongoing dose-ranging clinical trial for pheochromocytoma in adults.
The present study was designed to investigate the effects of flavonoids from aerial part of Scutellaria baicalensis Georgi (SSF) on potassium cyanide (KCN)-induced hypoxic cytotoxicity in rat pheochromocytoma cell line PC12, and to understand the probable mechanism.
KEY WORDS: adrenocortical carcinoma, Cushing's syndrome, hirsutism, pheochromocytoma, synaptophysin, virilization
58,59) Tricyclic antidepressants increase blood pressure in patients with panic disorders (60) or pheochromocytoma.