Giant Focal Nodular Hyperplasia Presenting as Pseudo-Mirizzi Syndrome

Abstract

Purpose: Focal nodular hyperplasia (FNH) is a relatively rare benign tumor of the liver typically seen in young to middle aged women. It is usually an incidental finding, with most patients being asymptomatic. We describe a previously unreported presentation of a FNH causing a Mirizzi like syndrome. Methods: An 18 year-old white female presented with two days of right upper quadrant and epigastric pain associated with nausea, vomiting and chills. She had no prior medical history other than eczema and asthma. She denied taking any prescription or over the counter medications including oral contraceptives. Liver biochemistries revealed elevated total bilirubin 2.9 gm/dL, alkaline phosphatase 270 U/L, AST 104 U/L, ALT 171 U/L and a normal alpha feto-protein. CT with contrast showed gallbladder thickening and a 9.0 × 7.4 cm mass in segment 4 of the liver demonstrating hyper enhancement on arterial phase with a central hypodense stellate focus (Fig. 1). An MRI revealed a 9.2 × 7.8 cm mass with a T2 hyperintense central scar with enlarged gallbladder with wall thickening. Finally, a hepatobiliary scan demonstrated radiotracer throughout the liver, prompt gallbladder visualization and a 0% gallbladder ejection fraction. Given the typical radiographic features of FNH seen with the above studies her mass was felt to be FNH presenting with a Mirizzi like syndrome.Figure 1: CT arterial phase showing giant FNH with central stellate scarResults: Due to the large size of FNH potentially leading to technical difficulty in performing a cholecystectomy, a cholecystostomy tube was placed to allow for gallbladder decompression. Subsequently, a right sided portal vein embolization was performed to allow left lobe hypertrophy of liver prior to successfully performing a right trisegmentectomy. The resected specimen revealed a 10.4 × 9.5 × 7.6 cm tan, heterogeneous, firm, diffusely nodular, well delineated mass with a central scar abutting the capsule and histology confirmed the presence of FNH. Gallbladder specimen did not reveal choleliths. Her post operative course was uncomplicated. Conclusion: This is the first case reported of a giant FNH presenting with Pseudo-Mirizzi syndrome.