Intrahepatic Lymphoid Follicles Comprising T and B Cells Mimic Hepatocellular Carcinoma in a Hepatitis B Patient.

Isolated intrahepatic lymphoid follicles (ILFs), also referred to as reactive lymphoid hyperplasia, are rare benign lymphoid proliferations that can closely mimic hepatocellular carcinoma (HCC) on imaging. This case highlights the diagnostic complexity of hepatic mass lesions in chronic hepatitis B patients, particularly when radiologic and serologic features raise concern for malignancy. A 60-year-old man with chronic hepatitis B presented with a liver mass, elevated alpha-fetoprotein levels, and imaging findings of heterogeneous arterial enhancement, all suggestive of HCC. Despite initial treatment with atezolizumab plus bevacizumab, the lesion progressed, leading to an extended left hepatectomy. Histopathological examination revealed well-formed lymphoid follicles with reactive germinal centers, without evidence of malignancy or granulomatous inflammation. Serum IgG was elevated, and ANA was positive, supporting the possibility of an underlying immune-mediated process. The patient showed clinical and serologic improvement following corticosteroid therapy, with no evidence of recurrence at 10-month follow-up. This case underscores the importance of histopathological confirmation in hepatic masses with atypical features and highlights the need to consider benign immune-related mimickers in the differential diagnosis, particularly in the era of immunotherapy.