Focal nodular hyperplasia of the liver: pathological analysis of 11 cases

BACKGROUND: Focal nodular hyperplasia (FNH) is a benign tumor-like lesion of the liver, predominantly affect- ing women. Its etiology is obscure and its pathogenesis is poorly understood. FNH should be differentiated from oth- er benign and malignant hepatic lesions. The aim of this study was to explore the pathological characteristics of FNH of the liver. METHODS: Eleven patients with FNH were studied retro- spectively by using hematoxylin and eosin, immunohisto- chemical and histochemical staining. RESULTS: In 8 female and 3 male FNH patients aged 19 to 54 years (mean 32), most of lesions showed central scars macroscopically. Microscopically 8 patients were found of classical type, 2 were of telangiectic type, and 1 was of mixed type. CONCLUSION: FNH is an uncommon benign hyperplastic lesion of the liver. It should be differentiated from hepato- cellular adenoma, alpha-fetoprotein negative hepatocellular carcinoma, and fibrolamellar carcinoma.