| − | A '''Tumor''' is an abnormal and functionless mass of [[tissue]] within a living body that is not inflammatory and arises from pre-existent tissue. This can either be benign (non-cancer) or malignant ([[cancer]]). Malignant tumors (cancer) are more invasive and can spread ([[metastasis|metastasize]]) to other parts of the body. However, even benign tumors can cause harm, by occupying space or exerting pressure on adjacent organs or tissues. | + | A '''Tumor''' is an abnormal and functionless mass of [[tissue]] within a living body that is not inflammatory and arises from pre-existent tissue. This can either be benign (non-cancer) or malignant ([[cancer]]). Malignant tumors (cancer) are more invasive and can spread ([[metastasis|metastasize]]) to other parts of the body. However, internally even benign tumors can cause harm, for example, by occupying space or exerting pressure on adjacent organs or tissues. |