Hepatic reactive lymphoid hyperplasia diagnosed through post-ablation liver tumor biopsy.

Hepatic reactive lymphoid hyperplasia (RLH), also known as hepatic pseudolymphoma, is a rare benign condition that predominantly affects middle-aged-to-elderly women and is often associated with autoimmune disorders. The imaging features of hepatic RLH frequently mimic those of malignant hepatic tumors, such as hepatocellular carcinoma (HCC), cholangiocarcinoma, or metastatic liver tumors, making its diagnosis based solely on imaging modalities challenging, often leading to unnecessary surgical resection. However, the optimal diagnostic strategy for hepatic RLH remains controversial. Here, we report a case of hepatic RLH diagnosed via biopsy following radiofrequency ablation (RFA). The hepatic nodule exhibited arterial-phase enhancement and portal-phase washout on contrast-enhanced ultrasonography, suggesting HCC. However, these findings were absent on contrast-enhanced computed tomography and gadolinium-ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging, suggesting an alternative diagnosis. Therefore, RFA was performed, followed by tumor biopsy for a definitive diagnosis. Histopathological examination and immunostaining of post-RFA biopsied specimens revealed lymphoid follicles composed of cells positive for CD3, CD10, and CD20, maintained polarization for Ki-67 positivity and negativity for diffuse Bcl-2 expression within the nodule, consistent with hepatic RLH. This case highlights the diagnostic utility of post-RFA biopsy, particularly when hepatic RLH is suspected, because it allows for both histological and immunohistochemical evaluation.