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 affecting women. Its etiology is obscure and its pathogenesis is poorly understood. FNH should be differentiated from other 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 retrospectively by using hematoxylin and eosin, immunohistochemical 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 hepatocellular adenoma, alpha-fetoprotein negative hepatocellular carcinoma, and fibrolamellar carcinoma.