A 46-year-old woman undergoes an abdominal hysterectomy for a "fibroid" uterus. The surgeon requests a frozen section on the tumor, which is deferred because of the lesion's degree of cellularity. Which of the following criteria will be used by the pathologist in determining benignancy versus malignancy in permanent sections?
Mitotic rate Cell pleomorphism Cell necrosis Nucleus-to-cytoplasm ratio