Adrenal pheochromocytoma: Keys to radiologic diagnosis.

Pheochromocytomas are adrenal paragangliomas. Potentially malignant, these tumors have a low incidence but clear importance. They can appear in various hereditary syndromes, especially in von Hippel-Lindau syndrome, multiple endocrine neoplasia-2 (MEN2), and familial paraganglioma syndromes. In sporadic cases, underlying genetic alterations are often found, and these findings are changing our understanding of the disease. Although these tumors can manifest with a characteristic clinical presentation, in 13.1%-57.6% of cases, it is the radiologist who first suggests the diagnosis, indicating analyses for catecholamines or nuclear medicine examinations. Radiologists should suspect a pheochromocytoma on detection of a well-delimited adrenal mass with rapid, intense enhancement that typically shows cystic and hemorrhagic phenomena, high T2 signal intensity, and the absence of macroscopic or microscopic lipids. The behavior in diffusion-weighted imaging usually does not provide very useful information. Approximately one-third of lesions show late washout similar to that seen with adenomas on CT. Percutaneous puncture should be avoided to avoid the risk of unleashing a severe hypertensive crisis.