Learning Radiology xray montage


General Considerations


  • Rare, catecholamine-secreting, neuroendocrine tumor usually found in medulla of the adrenal gland originating in the chromaffin cells
    • Extra-adrenal tumors called paraganglioneuromas
  • Most often produces epinephrine and norepinephrine (mostly) which is unregulated by any feedback mechanism
    • Sometimes dopamine is secreted
  • About 10 % are malignant
  • Occur at any age with peak in 3rd-5th decades, equal frequency in both sexes
  • Locations of extra-adrenal pheochromocytomas include the organ of Zuckerkandl which is close to the origin of the inferior mesenteric artery, bladder wall, heart, mediastinum, and carotid and glomus jugulare bodies

Clinical Findings

  • Headaches, palpitations and diaphoresis with hypertension, frequently episodic
  • Weakness
  • Nausea
  • Tremors
  • Anxiety
  • Weight loss
  • Plasma metanephrine measurements are most sensitive but have lower specificity
  • Twenty-four hour urine collection for creatinine, total catecholamines, vanillylmandelic acid and metanephrine has a lower sensitivity but higher specificity

Imaging Findings

  • Over 90%  located in adrenal, 98% in abdomen
  • Imaging studies are performed after the diagnosis is made on a biochemical basis
  • MRI is the preferred study
    • Hyperintense on T2-weighted images
    • No contrast required
  • CT scanning
    • Most have a pre-contrast attenuation >10 HU
    • Contrast was  thought to add the risk of inducing hypertensive crisis but no increased risk has been shown with low-osmolar contrast
    • Most lesions vigorously contrast-enhance (>80 HU) and have less than 60% washout of contrast on delayed images
  • PET scans have also proved helpful in finding the lesions

Differential Diagnosis

  • Adrenal adenomas
  • Adrenal carcinomas
  • Adrenal metastases


  • Von-Hippel Lindau disease
  • Neurofibromatosis
  • Multiple endocrine neoplasia (MEN) 2A (Sipple syndrome) and 2B
  • Tuberous sclerosis
  • Sturge-Weber syndrome


  • Surgical resection of the mass is the treatment of choice
  • Medical treatment is generally used pre-operatively, for management of the hypertensive crises and for treating metastatic disease, if present


  • Cardiac arrhythmias
  • Pulmonary edema
  • Dilated cardiomyopathy
  • Hypertensive encephalopathy
  • Stroke



Pheochromocytoma. Pre-contrast axial CT of abdomen shows a mass in the right adrenal gland (white arrow) The left adrenal gland is normal (yellow arrow). Following intravenous contrast (lower photo), the right adrenal mass enhances brightly (red arrow).
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