Focal nodular hyperplasia of the liver without central scar.

An unusual case of focal nodular hyperplasia (FNH) of the liver is presented. A 31-year-old male was admitted to our hospital for the evaluation of an hepatic mass 10 cm in diameter located in segment 4. Routine examinations including liver function tests were all normal. Hepatitis B surface antigen, hepatitis C virus antibody, alpha-fetoprotein were all negative. Imagining studies could not detect specific findings of FNH such as a central scar structure or a spoke-wheel appearance due to dilated tumor vessels coursing centrally followed by radiating peripheral coursing vessels. Extensive left lobectomy of the liver was performed. Histological examination of the specimen cut into 1-cm-thick slices revealed no central stellate scars. Preoperative diagnosis of FNH with imaging studies was difficult because of the absence of central scars.