Malignant tumors are cancerous tumors made up of cells that grow fast and often spread throughout the body, according to the American Brain Tumor Association. Malignant tumors are often more invasive than benign tumors. Malignant tumors are often life threatening and require immediate treatment by a cancer specialist or physician
The term "malignant" frequently indicates that a high probability exists for the tumor full of cancerous cells to spread to other tissues via the blood stream or lymph vessels, according to the Cleveland Clinic. Sarcomas, malignant soft tissue tumors, are rare and account for about 1 percent of all malignant tumors. Carcinomas, malignant tumors that form in glands or organs of the body, are much more common.