[Atypical MRI appearance of hepatic focal nodular hyperplasia]

To explore the atypical MRI findings of focal nodular hyperplasia (FNH) of the liver.

Retrospective analyses were conducted for 13 cases (10 males and 3 females) confirmed pathologically as FNH after surgery or biopsy with liver MRI examination from January 2012 to June 2015 in PLA General Hospital.

There were 22 focal lesions in 12 cases, and diffuse pattern in 1 case. In the 22 focal lesions, there were 3 lesions with fatty change, 1 lesion with hemorrhage, 7 lesions with pseudo-capsule, regarding to dynamic contrast-enhanced pattern: 12/22 lesions with gradually increasing enhancement, 3/22 lesions with rapid wash-in and wash-out, and 7/22 lesions with rapid wash-in and slow wash-out. The hepatocyte-specific agent examinations were performed in 20/22 lesions, and 20/20 lesions showed iso- to hyper-intensity to the liver parenchyma in the hepatocyte phase.There was 1 case (female) showing diffuse lesions with obvious fatty change, and all the lesions took up the hepatocyte-specific agent in hepatocyte phase.

The atypical focal nodular hyperplasia often occurs in middle age males and could demonstrate fatty change, hemorrhage, pseudo-capsule, various enhancement patterns. And when the FNH showed atypical routine MRI findings, the use of the hepatocyte-specific agent could facilitate the diagnosis.