A soft-tissue sarcoma STS is a malignant tumor , a type of cancer , that develops in soft tissue. They may be superficial or deep-seated. Any such unexplained mass must be diagnosed by biopsy. There are many different types, many of which are rarely found. The names of several sarcomas have changed over time. In their early stages, soft-tissue sarcomas usually do not cause symptoms. Because soft tissue is relatively elastic, tumors can grow rather large, pushing aside normal tissue, before they are felt or cause any problems.
The first noticeable symptom is usually a painless lump or swelling. As the tumor grows, it may cause other symptoms, such as pain or soreness, as it presses against nearby nerves and muscles. If in the abdomen it can cause abdominal pains commonly mistaken for menstrual cramps, indigestion, or cause constipation.
Most soft-tissue sarcomas are not associated with any known risk factors or identifiable cause. There are some exceptions:. The only reliable way to determine whether a soft-tissue tumor is benign or malignant is through a biopsy. The two methods for acquisition of tumor tissue for cytopathological analysis are:. A pathologist examines the tissue under a microscope. The pathologist may be the most important person in the treatment of sacomas, because they are responsible for making the proper diagnosis.
Pathologists at expert sarcoma centers are invaluable in identifying the type of sarcoma responsible for a patient's symptoms. If cancer is present, the pathologist can usually determine the type of cancer and its grade.
Here, grade refers to a scale used to represent concisely the predicted growth rate of the tumor and its tendency to spread, and this is determined by the degree to which the cancer cells appear abnormal when examined under a microscope. Low-grade sarcomas, although cancerous, are defined as those that are less likely to metastasise.
