The prevalence of benign mass-forming liver lesions has risen significantly in recent years, largely due to advances in diagnostic imaging. These lesions may be neoplastic or non-neoplastic, each with distinctive prognostic and management implications. Among benign mass-forming lesions of the liver, hemangiomas are the most common, followed by focal nodular hyperplasia (FNH), which occurs approximately ten times more frequently than hepatocellular adenomas (HCA), the third most common benign liver tumor. Recent advancements have refined the classification of HCA based on histomorphology and molecular signatures. This chapter provides a detailed overview of histologic features and diagnostic approaches for FNH and HCA, emphasizing the need for pathologists to distinguish the two. It also discusses updated molecular subtypes of HCA and their relevance in clinical management and follow-up. Additionally, less common entities, such as FNH-like lesions and atypical lesions, are explored, offering broader insight into this complex spectrum of liver pathology.