Hepatocellular carcinoma is described as:

Hepatocellular carcinoma (HCC) is characterized by its unifocal, multifocal, and diffusely invasive nature. This means that the tumor can appear as a single mass (unifocal) or can present in multiple areas of the liver (multifocal). Additionally, its infiltrative behavior allows the cancer to spread within the liver tissue, making it difficult to define clear margins, which is a critical feature of its pathology. This characteristic is vital for proper diagnosis and treatment planning.

The other descriptions, such as being discrete and encapsulated or unifocal with clear margins, do not reflect the aggressive nature and the typical presentation of HCC. While some tumors may appear unifocal, they often do not exhibit clear boundaries due to their invasive growth, which supports the notion of multifocal involvement in many cases. Moreover, while age can be a factor in the incidence of HCC, it is not exclusively found in individuals over 60, and its occurrence can be seen in younger populations, particularly in cases associated with chronic liver disease or viral hepatitis.