Background: Although reactive lymphoid hyperplasia (RLH) can be found in various organs, including the gastrointestinal tract, orbit, lung, and skin, its occurrence in the liver is rare.
Case Report: We report the case of a 47-year-old RLH woman who was identified with RLH of the liver during clinical follow- up of primary biliary cirrhosis. The mass, found incidentally during a medical examination, appeared on ultrasonogram as a hypoechoic mass in the 7th segment of the liver. Further analyses using composed tomography, magnetic resonance imaging, and angiography suggested malignancy, and we performed lateral segmentectomy of the liver. Histologically, the tumor was composed of lymphoid follicles with germinal centers that expressed κ and λ light-chain B-cell markers at equal frequency, and no IgH gene rearrangements were detected in Southern blots. Based on these results, we identified the lesion as RLH.
Conclusions: We suggest that this diagnosis be taken into consideration in other cases involving a space-occupying liver mass associated with autoimmune disease.

Keywords: Liver Cirrhosis, Biliary - surgery, Liver - surgery, Gene Rearrangement, B-Lymphocyte, Heavy Chain - genetics, Aged, 80 and over, Pseudolymphoma - surgery, Tomography, X-Ray Computed