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Pheochromocytoma

Practice Essentials

A pheochromocytoma (see the image below) is a rare, catecholamine-secreting tumor derived from chromaffin cells. The term pheochromocytoma (in Greek, phios means dusky, chroma means color, and cytoma means tumor) refers to the color the tumor cells acquire when stained with chromium salts.

Axial, T2-weighted magnetic resonance imaging (MRI

Axial, T2-weighted magnetic resonance imaging (MRI) scan showing large left suprarenal mass of high signal intensity on a T2-weighted image. The mass is a pheochromocytoma.

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About 30% of pheochromocytomas occur as part of hereditary syndromes. Although pheochromocytomas have classically been associated with 3 syndromes—von Hippel-Lindau (VHL) syndrome, multiple endocrine neoplasia type 2 (MEN 2), and neurofibromatosis type 1 (NF1)—there are now 10 genes that have been identified as sites of mutations leading to these tumors. These different genes produce pheochromocytomas with different ages of onset, secretory profiles, locations, and potential for malignancy.

Because of excessive catecholamine secretion, pheochromocytomas may precipitate life-threatening hypertension or cardiac arrhythmias.
If the diagnosis of a pheochromocytoma is overlooked, the consequences can be disastrous, even fatal; however, if a pheochromocytoma is found, it is potentially curable. (See Pathophysiology, Prognosis, and Treatment.)

About 85% of pheochromocytomas are located within the adrenal glands, and 98% are within the abdomen. When such tumors arise outside of the adrenal gland, they are termed extra-adrenal pheochromocytomas, or paragangliomas.

Extra-adrenal pheochromocytomas develop in the paraganglion chromaffin tissue of the nervous system. They may occur anywhere from the base of the brain to the urinary bladder. Common locations for extra-adrenal pheochromocytomas include the organ of Zuckerkandl (close to the origin of the inferior mesenteric artery), bladder wall, heart, mediastinum, and carotid and glomus jugulare bodies. (See Workup.)

Malignancy

Approximately 10% of pheochromocytomas and 35% of extra-adrenal pheochromocytomas are malignant. Only the presence of metastases defines malignancy. However, specific histologic features help to differentiate adrenal pheochromocytomas with a potential for biologically aggressive behavior from those that behave in a benign fashion. Among the features that suggest a malignant course are large tumor size and an abnormal DNA ploidy pattern (aneuploidy, tetraploidy).
 Common metastatic sites include bone, liver, and lymph nodes.

For discussion of pheochromocytoma in children, see the Medscape Drugs & Diseases article Pediatric Pheochromocytoma.

Signs and symptoms of pheochromocytoma

Classically, pheochromocytoma manifests as spells with the following 4 characteristics:

Headaches

Palpitations

Diaphoresis

Severe hypertension

Typical patterns of the spells are as follows:

Frequency may vary from monthly to several times per day

Duration may vary from seconds to hours

Over time, spells tend to occur more frequently and become more severe as the tumor grows

The following may also occur during spells:

Tremor

Nausea

Weakness

Anxiety, sense of doom

Epigastric pain

Flank pain

Constipation

Clinical signs associated with pheochromocytomas include the following:

Hypertension: Paroxysmal in 50% of cases

Postural hypotension: From volume contraction

Hypertensive retinopathy

Weight loss

Pallor

Fever

Tremor

Neurofibromas

Tachyarrhythmias

Pulmonary edema

Cardiomyopathy

Ileus

Café au lait spots

See Clinical Presentation for more detail.

Diagnosis of pheochromocytoma

Diagnostic tests for pheochromocytoma include the following:

Plasma metanephrine testing: 96% sensitivity, 85% specificity

24-hour urinary collection for catecholamines and metanephrines: 87.5% sensitivity, 99.7% specificity

Test selection criteria include the following:

Use plasma metanephrine testing in patients at high risk (ie, those with predisposing genetic syndromes or a family or personal history of pheochromocytoma)

Use 24-hour urinary collection for catecholamines and metanephrines in patients at lower risk

Imaging studies should be performed only after biochemical studies have confirmed the diagnosis of pheochromocytoma. Studies are as follows:

Abdominal CT scanning: Has accuracy of 85-95% for detecting adrenal masses with a spatial resolution of 1 cm or greater

MRI: Preferred over CT scanning in children and pregnant or lactating women; has reported sensitivity of up to 100% in detecting adrenal pheochromocytomas

Scintigraphy: Reserved for biochemically confirmed cases in which CT scanning or MRI does not show a tumor

PET scanning: A promising technique for detection and localization of pheochromocytomas

Additional studies to rule out a familial syndrome in patients with confirmed pheochromocytoma include the following:

Serum intact parathyroid hormone level and a simultaneous serum calcium level to rule out primary hyperparathyroidism (which occurs in MEN 2A)

Screening for mutations in the
ret proto-oncogene (which give rise to MEN 2A and 2B)

Genetic testing for mutations causing the MEN 2A and 2B syndromes

Consultation with an ophthalmologist to rule out retinal angiomas (VHL disease)

See Workup for more detail.

Management of pheochromocytoma

Surgical resection of the tumor is the treatment of choice and usually cures the hypertension. Careful preoperative treatment with alpha and beta blockers is required to control blood pressure and prevent intraoperative hypertensive crises.

Preoperative medical stabilization is provided as follows:

Start alpha blockade with phenoxybenzamine 7-10 days preoperatively

Provide volume expansion with isotonic sodium chloride solution

Encourage liberal salt intake

Initiate a beta blocker only after adequate alpha blockade, to avoid precipitating a hypertensive crisis from unopposed alpha stimulation

Administer the last doses of oral alpha and beta blockers on the morning of surgery

See Treatment and Medication for more detail.

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