How is tumor grade determined?

If a tumor is suspected to be malignant, a doctor removes all or part of it during a procedure called a biopsy. A pathologist (a doctor who identifies diseases by studying cells and tissues under a microscope) then examines the biopsied tissue to determine whether the tumor is benign or malignant. The pathologist also determines the tumor’s grade and identifies other characteristics of the tumor. The NCI fact sheet Pathology Reports describes the type of information that can be found in a pathologist’s report about the visual and microscopic examination of tissue removed during a biopsy or other surgery.