To understand pheochromocytoma and its etiology, epidemiology, signs and symptoms, diagnosis,staging, imaging, treatment and prognosis.

The adrenal glands are triangular shaped endocrine glands that sit on top of the kidneys. The adrenalglands are made up of 2 parts; adrenal cortex and medulla. Within the medulla, it containsneuroendocrine cells known as chromaffin cells which are also found in other ganglia of thesympathetic nervous system.

Pheochromocytoma is a rare cancer of the adrenal glands and it arises from chromaffin cells. Aspheochromocytomas usually arise from chromaffin cells, they are also called chromaffin tumours. 90%of pheochromocytomas are typically located in the adrenal medulla of the adrenal glands. However,this tumour can also be found outside the adrenal glands such as the heart and bladder and thesechromaffin cancers are referred to as paragangliomas.

Dependent on the presentation of significant catecholaminemetabolites can be measured through either blood or

Urine test 7:

• Gold standard for diagnosis because catecholaminesvary

• Healthy people excrete only very small amounts

• May be inconvenient

• Gives the highest reliability and specificity results

Blood (plasma) test 8:

• More convenient than the urine test

• Less sensitive method

Adrenal gland function to secrete the epinephrine and norepinephrine hormones, also known asadrenaline and nor-adrenaline. When adrenaline is released from the adrenal gland into the bloodstream, its function is to help regulate factors in the body such as blood pressure and heart rate.Pheochromocytomas cause the adrenal medulla to secrete too much adrenaline resulting in high bloodpressure. This disease can be fatal if left unrecognised as it gives rise to a surgically correctable formof hypertension 1.

The cause of pheochromocytoma is still unknown. Whilst many of these cases arise sporadically, 25%of pheochromocytomas are inherited from germ line mutations in the RET, VHL, NF1, SDHB, SDHC orSDHD genes 2. These genes control various factors such as cell cycle progression in the Krebs cycle,glucose metabolism and oxygen sensing only to name a few.

•Very uncommon disease

• Usually gives false positive results

Imaging studies are usually done after the diagnosisepinephrine, norepinephrine and their metabolites are

There are 4 stages of pheochromocytoma and they

•Localized benign pheochromocytoma – tumor is found in one area and has not spread to other tissue; may not be cancerous

•Regional pheochromocytoma – cancer has spread to lymph nodes and other tissue around the area

•Metastatic pheochromocytoma – cancer has spread to other parts of the body

•Recurrent pheochromocytoma – cancer has returned after treatment

•Very uncommon disease

• Can occur at any age, mostly young adults

• Equal chance of occurrence in males and females 3

• Can affect either one or both adrenal glands, or outside the adrenal glands (extra-adrenal)

• Present only in < 1% of hypertensive patients

• Extra-adrenal cases have higher chance of malignancy 4

Many imaging modalities may be performed to determine

http://emedicine.medscape.com/article/379861-overview

Fig. 1 CT slice

Related to sympathetic nervous system hyperactivity:

•Headache

•Excessive sweating

•Elevated heart rate 5

Other symptoms include tremor, nausea, vomiting and fever.

•Familial / hereditary

1. Multiple endocrine neoplasia (MEN)

2. Von Hippel-Lindau syndrome

• Without any family history (sporadic) 5

modalities may include that of CT, ultrasound, plain films

The initial imaging findings of a benign and a malignantwith the presence of metastasis would definepheochromocytoma may vary from 1-20 cm 10 and usually

On CT it appears as round or oval discrete mass withand cystic changes may be present 10 (Figure 1).

Ultrasound may also be used to diagnose pheochromocytomahypoechoic with few echogenic areas 10 (Figure 2).

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Other symptoms include tremor, nausea, vomiting and fever.

Signs and symptoms usually follow a pattern of high blood pressureand then low blood pressure. High blood pressure usually begins witha change in breathing and a pounding or forceful heartbeat 6.

J.T. Nguyen1, B.L. Chia2, T.N. Ha3

1,2, 3 University of South Australia, Adelaide, AUSTRALIA

catecholamine excess. Levels of catecholamine and itsor urine tests 4.

catecholamines are released throughout the day and the levels

Radiographs tend to have many limitations in imaging pheochromocytomas. However, largeadrenal masses compressing the upper pole of the kidney may be discovered incidentally onintravenous urograms and abdominal aortograms (Figure 3). In some cases, enlargement of the

•http://emedicine.medscape.com/article/379861-imaging

Fig. 3 Abdominal Aortogram Fig. 4 T1-weighted axial MRI Fig. 5 T2-weighted coronal MRI

RadioGraphics 2004 RadioGraphics 2004

diagnosis to look at the adrenal glands if the levels ofare greater than 2 times the normal level.

include:

is found in one area and has not spread to other

cancer has spread to lymph nodes and other tissue around the area

cancer has spread to other parts of the body

cancer has returned after treatment 9

intravenous urograms and abdominal aortograms (Figure 3). In some cases, enlargement of theadrenal medullary may be seen on an abdomen x-ray due to a pheochromocytoma; howeverthese are all incidental findings.

The pheochromocytomas are relatively hypodense or isodense in comparison to the liver on T1weighted spin echo (SE) images (Figure 4) and are highly intense on T2 weighted SE images(Figure 5). The reason for the difference between the two images is unknown however this may bedue to the water composition in the tissue.

MRI is considered to be more advantageous in screening for pheochromocytoma due to thesuperior tissue characterisation capability in conjunction with its multicoplanar abilities greater thanthat of CT 12.

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determine and diagnose Pheochromocytoma. Thesefilms and MRI.

The surgical treatment of choice for pheochromocytoma is laparoscopic adrenalectomy. Thisprocedure involves the removal of the adrenal glands. Careful planning prior to surgery isnecessary for the most favorable treatment outcome for the lesion 13. Excessive manipulation of thetumor should be avoided during the surgery to avoid life threatening hypertension.

http://medind.nic.in/ibn/t05/i4/ibnt05i4p433.pdf

Fig. 2 Ultrasound image

Medical treatment followed by surgical removal ofthe lesion is the technique used to treatpheochromocytomas. Adequate medical treatment iscritical to provide a good outcome from surgery.Phenoxybenzamine is commonly administered topatients to increase blood volume and also blockexcessive amounts of epinephrine and norepinephrinesecreted by the tumour 13. A beta-blocker is thenprescribed to the patient to control the effects of theexcessive production of adrenaline from the tumor.

films and MRI.

malignant pheochromocytomas are almost identical, onlydefine that a lesion is malignant. The size of a

usually seen when they are larger than 3cm 11.

with homogenous density. Central necrosis, calcification

pheochromocytoma. In ultrasound, the lesions appears

In cases where pheochromocytomas are malignant, chemotherapy or radiation therapy may beutilised after surgery 14.

The pheochromocytoma prognosis is dependant on the staging of the pheochromocytoma and thepatient’s age and health condition 9. Benign pheochromocytomas within the adrenal gland haveexcellent outcomes after adrenalectomy. Recurrent, metastatic pheochromocytoma, or tumours thatare unable to be removed surgically have a fair to poor outlook. Patients who are pregnant withPheochromocytoma have a poor outcome; where the mortality rate is about 50% for both motherand fetus 15.