Histologic scoring of liver biopsy in focal nodular hyperplasia with atypical presentation

The contribution of radio-guided transcutaneous biopsy in the diagnosis of focal nodular hyperplasia (FNH) of the liver was compared with the findings on surgical specimens to assess its contribution in clinical and radiologic atypical cases. This retrospective study involved 30 patients with atypical tumors on imaging who underwent liver biopsy and then surgery. All surgical specimens were diagnosed as FNH, either classical (n = 18) or nonclassical (n = 12). Imaging data were reviewed according to 4 radiologic criteria on magnetic resonance imaging (MRI) and/or computed tomography (CT) scan (hypervascularity, homogeneity, nonencapsulation, and presence of a central scar), and classified depending on the number of criteria found (group I, 4 of 4; group II, 3 of 4; group III, 2 or fewer). Histologic assessment of ultrasound (US)-guided liver biopsy recorded major diagnostic features (fibrous bands, thick-walled vessels, reactive ductules, and nodularity) and minor features (sinusoidal dilatation and perisinusoidal fibrosis). "Definite FNH" (3 or 4 major features) was diagnosed in 14 biopsies, "possible FNH" (2 major and 1 or 2 minor features) in 7 cases, and "negative for FNH" (2 or fewer major features without minor features) in 9 cases. The diagnosis of FNH on biopsy was reached in 14 cases (58.3%) in patients with 2 or fewer imaging criteria (group III; n = 24). Biopsies with a diagnosis of "possible FNH" corresponded to a large proportion of telangiectatic-type FNH on the specimen. In conclusion, liver biopsy does not appear to be necessary in cases in which imaging is typical. However, the absence of radiologic diagnostic criteria in FNH does not preclude a positive diagnosis on liver needle biopsy. Using the proposed histologic scoring system, surgical management may be avoided in these cases.