This cancer will start in one place, and be very unpredictable. It can stay in one place, it can spread widely all over the body, it can spread locally or by metastasizing. It can be quiet for a long time, and then erupt after 20 years. It is a resistant cancer...not very responsive to chemotherapy or radiation. 

The best outcome occurs when it is taken out surgically with wide margins, early, while small and before it spreads.