Autoimmune Hepatitis: Histopathological Diversity and Its Clinical Implications.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease characterized by diverse clinical and histological manifestations. Accurate histopathological evaluation plays a critical role in determining disease activity, guiding treatment strategies, and predicting prognosis. However, due to its broad histological spectrum, AIH can resemble other liver disorders such as drug-induced liver injury (DILI) and viral hepatitis, making differential diagnosis challenging. In particular, acute-onset AIH often lacks typical serological markers, further complicating timely diagnosis. Liver biopsy provides essential information that cannot be obtained through serological or imaging studies alone, such as the distribution and pattern of hepatic injury and the presence of bile duct involvement. Furthermore, with the increasing prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD), distinguishing AIH from overlapping or coexisting liver diseases has become increasingly important. This review highlights the characteristic histological features of AIH, discusses key differential diagnoses, and addresses current limitations in the diagnostic approach.