What is considered a large mass on the liver?

A benign tumor?: Benign neoplasms of the liver are usually slow-growing (they appear relatively stable in size on sequential liver imaging) isolated space-occupying structures that are not expected to turn into cancer. Examples include: cysts, focal nodular hyperplasia, hemangiomas, adenomas, cholangiomas, cystadenomas, mesenchymal hamartomas. Giant (>4cm) tumors can cause mass effect, thrombosis, pain.