Pheochromocytoma with posthemorrhagic cystic degeneration: magnetic resonance imaging findings.

We describe in vivo and in vitro magnetic resonance imaging (MRI) findings of a pheochromocytoma with posthemorrhagic cystic degeneration in a 74-year-old man. The in vivo MR images showed the mass as an area of homogeneous moderate hyperintensity with a central area of intense hyperintensity outlined by a thin hypointense rim on a T2-weighted image. The in vitro MR images showed a hyperintense rim around the central cystic area consistent with hemorrhage on T1-weighted gradient-echo images with short echo times (1.6 and 4.2 msec) and more distinctly revealed the blurring effect due to susceptibility of hemosiderin on those with long echo times (6 and 8 msec). Hemosiderin deposition caused by intraparenchymal hemorrhage in the pheochromocytoma can be appreciated on spoiled gradient-echo images with different echo times, which is ordinarily included in the MRI protocol as phase-shift imaging.