What are the odds of benign tumors becoming malignant?

Benign tumors: It really depends on the organ/tumor involved. Some benign tumors can become malignant but that's generally a rare occurrence. Speak with your doctor about your concerns.

Extremely rare: The majority of benign tumors such as lipoma, fibroma or schwannoma remain benign. Malignant transformation requires the addition of an oncogenic factor not present in the benign lesion. The EBV virus in addition, turns on telomerase that lends to immortality of the cell required by the malignant lesion. At times benign nevi over a period of time can also transform to a malignant melanoma.