Question

Describe the methods used to diagnose a pheochromocytoma.

Answer 1

Pheochromocytoma is the condition of neuroendocrine tumor of the medulla of adrenal glands or extra adrenal chromaffin tissue which results in secretion of high amount of catecholamines especially norepinephrine and less amount of epinephrine.

Diagnosis

The tests to diagnose Pheochromocytoma are as described below:

1. Laboratory tests

The following tests are done to measure levels of adrenaline, noradrenaline or byproducts of these hormones in body:

• 24-hour urine test. During every time of urination urine sample is taken throughout  24-hour period for catecholamines and metanephrines testing .
• Blood test. Blood test is required which includes Plasma metanephrine testing.

2. Imaging tests

If the results of laboratory tests indicate the possibility of a pheochromocytoma or paraganglioma, then imaging test is done to locate position of tumor. The following imaging test are done:

• CT scan, a specialized X-ray technology
• MRI, which uses radio waves and a magnetic field to produce detailed images
• M-iodobenzylguanidine (MIBG) imaging, a scanning technology that can detect tiny amounts of an injected radioactive compound taken up by certain tumors
• Positron emission tomography (PET), a scanning technology that can also detect radioactive compounds taken up by a tumor

3. Genetic testing

If tumor is detected in adrenal glands then to determine if a pheochromocytoma is related to an inherited disorder, presence of cancerous cells or malignant cells genetic testing is to be done.