A difference between a benign tumor and malignant cancer is the following A difference between a benign tumor and malignant cancer is the following: Benign cells are frequently caused by viruses, while malignant cells are rerel, if ever. Benign tumor cells sill have control of the cell cycle, while malignant cells do not. Benign tumors are small, while malignant tumors can grow to be quite large. Benign cells do not leave the tumor to e stabblish new tumors, while malignant cells may. O Benign tumor cells generally do not have mutations, while malignant cels do..