Noncancerous Versus Cancerous Tumors
A tumor is a mass of abnormally dividing cells. There are two types of tumors:
Benign tumors are slow-growing, well-defined tumors that do not spread. In rare cases, untreated benign tumors may be life-threatening if they affect a vital organ. Because they do not invade the surrounding tissue, benign tumors are relatively easy to remove surgically, depending on their location. In some cases, benign tumors may become malignant, though this usually takes a long time (sometimes decades) if it happens at all. Benign tumors generally do not cause death or serious illness unless they are very large (such as some benign ovarian tumors), or if they affect a critical organ that makes it difficult to operate on and remove them (such as tumors in the brain).
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