In diagnosing malignant soft tissue tumors, it is important to know whether or how far the tumor has spread in the body. In more than 90% of patients with a malignant tumor, there are no visible signs the tumor has spread. This does not necessarily mean that the tumor hasn't spread; it may mean that the scattered cells can't be picked up by current medical tests and imaging.
If the tumor has spread, removing the visible part of the tumor will not cure the patient.
An experienced pathologist can examine a sample of the tumor under a microscope. He or she can then group it according to how likely it is to have spread. A tumor that is classed as high grade has a 70 to 90% chance of having spread. A low-grade tumor has less than a 15% chance of spreading.