- “ Pheochromocytomas are often considered the great mimicker of other adrenal tumors. Because of their varied clinical, imaging, and pathologic appearances, accurate diagnosis can be challenging.”
Pheochromocytoma: The Range of Appearances on Ultrasound, CT, MRI, and Functional Imaging
Leung K et al.
AJR 2013; 200:370-378 - Pheochromocytoma: Facts
90% are sporadic and 10% are part of syndromes
- von Hippel-Lindau syndrome (10-26%)
- MEN Type II (50%)
- Neurofibromatosis Type 1 (1%)
- Pheochromocytoma-Paraganglioma Syndromes Associated with SDHB and SDHD Mutation - Pheochromocytoma: CT Findings
- Calcifications are found in 10% of Pheochromocytomas
- Pheochromocytomas typically are vascular on early phase CT scans
- Pheochromocytomas can have a 50% washout value and behave just like an adenoma
- In the absence of metastases it is hard to diagnosis whether or not a Pheochromocytoma is malignant
- Pheochromocytoma
- 0.1 – 0.2 % of adults with hypertension
- “new onset, refractory, paroxysmal or recently exacerbated”
- Palpitations, headache, diaphoresis, flushing
- May be asymptomatic - CT of Pheochromocytoma
- Highly variable imaging appearance
- Homogeneous or heterogeneous
- May be brightly enhancing
- Cystic degeneration
- Calcification in up to 1/3 - Pheochromocytoma Mimic
- Renal cell carcinoma metastases
- Hypervascular
- Can have central necrosis
- Can washout like an adenoma
- Hyperenhancing Adrenals
In the setting of shock
-Trauma
-Sepsis
-Pancreatitis
-Hemorrhage induced hypotension
Poor prognostic indicator - Adrenocortical Carcinoma
1st and 4th decades of life
55% are functional
-Cushing syndrome
-Feminization
-Virilization
-Mixed Cushing/virilization
Hypertension common with functional - CT of Pheochromocytoma
-Highly variable imaging appearance
-Homogeneous or heterogeneous
-May be brightly enhancing
-Cystic degeneration
-Calcification in up to 1/3 - Pheochromocytoma: Diagnosis
24-hour urine to assess for:
-Vanillylmandelic acid (VMA)
-Catecholamines
-Metanephrines - Pheochromocytoma
-0.1 – 0.2 % of adults with hypertension
-“new onset, refractory, paroxysmal or recently exacerbated”
-Palpitations, headache, diaphoresis, flushing
-May be asymptomatic - Adrenal: Extraadrenal Paragangliomas: CT Findings
- Homogeneous or heterogeneous hyperenhancing mass
- Range in size from 1 cm to over 20 cm
- Common locations are carotid body, jugular foramen, aorticopulmonary region, posterior mediastinum, abdominal paraaortic region including Organ of Zuckerkandl, and pelvis - Adrenal: Paraganglioma: Facts
- Neuroendocrine tumor which arises from the paraganglionic cells
- Pheochromocytoma is a paraganglioma of the adrenal gland
- Usually 4th and 5th decades of life
- 10% are clinically silent and picked up incidentally - Adrenal: Paraganglioma: Facts
- Familial Paragangliomas are 10% of cases
- 35-50% of familial cases are multicentric
- Occur with MEN IIA and IIB, tuberous sclerosis, neurofibromatosis, and von Hippel Lindau disease. Also part of Carney’s triad with gastric leiomyosarcoma, chondroma and extraadrenal paraganglioma - Adrenal: Paraganglioma "Although paragangliomas can occur in a variety of anatomic locations, the majority are seen in relatively predictable regions of the body." Extraadrenal Paragangliomas of the Body: imaging Features Lee KY et al. AJR 2006; 187:492-504
- "This case of an incidental pheochromocytoma showing contrast medium washout greater than 50% on delayed imaging reinterates the importance of performing a biochemical profile in any patient with an incidental discovered adrenal mass." Incidental Pheochromocytoma Mimicking Adrenal Adenoma Because of Rapid Contrast Enhancement Loss Yoon JK et al AJR 2006; 187:1309-1311.
- "Noncontrast 37 HU early phase (60 seconds) 127 HU delayed phase (15 minutes) 62 HU washout 72%" Incidental Pheochromocytoma Mimicking Adrenal Adenoma Because of Rapid Contrast Enhancement Loss Yoon JK et al AJR 2006; 187:1309-1311.
- Pheochromocytoma: Facts
- May result in life threatening hypertension or cardiac arrhythmias because of excessive catecholamine secretion
- Occurs in 0.1-0.9% of hypertensive patients
- 10% of patients asymptomatic - Pheochromocytoma: CT Findings
- Mass may be solid or cystic
- Most have attenuation value on noncontrast CT of >10 HU
- Fat may be seen in a pheo
- Variable washout curves - "On CT, pheochromocytomas may have attenuation values less than 10 HU and also may display more than 60% washout of contrast agents on delayed scanning.Adrenal pheochromocytoma should also be included with adenomas in the differential diagnosis both for masses with low attenuation on unenhanced CT and for lesions exhibiting a high percentage of contrast washout."
Low-Density Pheochromocytoma on CT: A Mimicker of Adrenal Adenoma Blake MA et al. AJR 2003;181:1663-1668
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