Clinical, Morphologic, and Molecular Features Defining So-Called Telangiectatic Focal Nodular Hyperplasias of the Liver

Background & Aims: Telangiectatic focal nodular hyperplasia (TFNH) of the liver is generally believed to belong to the focal nodular hyperplasia (FNH) family. The aim of this study was to use molecular markers, in addition to morphologic features, to better characterize TFNH. Methods: Thirteen patients with TFNH were compared with 28 patients with FNH and 17 patients with hepatocellular adenoma. Full clinical and morphologic data were analyzed. Molecular markers included determination of clonality by examining the active X chromosome, genome-wide allelotyping, a search for hepatocyte nuclear factor 1α (HNF1α) mutations, and determination of ANGPT1/ANGPT2 transcript levels. Results: No clinical differences were evident between patients with TFNH and adenoma; in particular, bleeding was observed in 77% and 53% of the cases, respectively. Patients with TFNH were more likely to experience nodule recurrence and the presence of multiple nodules than those with either FNH or adenoma. All TFNH and adenoma samples that were available for analysis were monoclonal, in contrast to 40% of the FNH samples. Chromosome losses confirmed monoclonality and were significantly less frequent in TFNH and FNH (22% and 26%) than in adenoma (53%). HNF1α mutations were found exclusively in half of the adenomas. ANGPT2 was overexpressed in TFNH and down-regulated in adenoma (P < .01) and FNH (P < .0005). Conclusions: TFNHs are monoclonal lesions frequently subject to bleeding that are similar to adenomas not carrying HNF1α mutations and require a similar type of treatment. However, morphologic and molecular data support the hypothesis that TFNH is a separate entity.