<em>1. Some tumors are benign, which means they form in only one spot without spreading to surrounding tissue. Malignant tumors are cancerous and can spread to nearby tissue.</em>
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<em>2. A benign tumor is not a malignant tumor, which is cancer. It does not invade nearby tissue or spread to other parts of the body the way cancer can. In most cases, the outlook with benign tumors is very good. But benign tumors can be serious if they press on vital structures such as blood vessels or nerves.</em>
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<em>3. Although some tumors are benign and consist of noncancerous cells, others are malignant. Malignant tumors are cancerous, and the cells can spread to other parts of the body.</em>
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<em>4. Malignant tumors are cancerous (ie, they invade other sites). They spread to distant sites via the bloodstream or the lymphatic system. This spread is called metastasis.</em>
