Pheochromocytoma: an imaging chameleon.
Pheochromocytomas are rare catecholamine-secreting tumors with many clinical and imaging manifestations. They may produce overwhelming cardiovascular crises if the diagnosis is not made or if appropriate treatment is delayed. It is thus important to recognize both their characteristic and atypical imaging appearances. Pheochromocytomas are encountered, sometimes unexpectedly, across a range of imaging modalities. They are characteristically solid, hypervascular masses with high signal intensity on T2-weighted magnetic resonance (MR) images. A wide spectrum of imaging appearances is seen, however, and pheochromocytomas may mimic other adrenal lesions, both benign and malignant. They may be dark on T2-weighted MR images, in contrast to their more classic bright T2-weighted appearance. Other atypical features include fatty, hemorrhagic, cystic, and calcific changes. Pheochromocytomas may contain sufficient fat to be mistaken for an adenoma at computed tomography (CT) or MR imaging. They may also demonstrate rapid contrast material washout and be mistaken for an adenoma owing to their deenhancement profile; however, their washout pattern can be inconsistent. The appearance of pheochromocytomas at radionuclide imaging is also unpredictable. These characteristics at CT, MR imaging, and scintigraphy pose diagnostic challenges, since they allow pheochromocytomas to mimic many other adrenal masses. Pheochromocytoma is an important, often clinically occult neoplasm with devastating consequences if overlooked. Radiologists must be aware of the various forms that pheochromocytomas can assume at imaging.
Blake
Michael A
MA
Department of Radiology, Division of Abdominal Imaging and Intervention, Massachusetts General Hospital, White 270, 55 Fruit St, Boston, MA 02114, USA. mblake2@partners.org
Kalra
Mannudeep K
MK
Maher
Michael M
MM
Sahani
Dushyant V
DV
Sweeney
Ann T
AT
Mueller
Peter R
PR
Hahn
Peter F
PF
Boland
Giles W
GW
D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D011859:Radiography