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How do malignant tumors differ from benign tumors?
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cancer
View through an endoscope of a polyp, a benign precancerous growth projecting from the inner lining of the colon.
Malignant and benign tumors are both abnormal growths of cells, but they differ significantly in their behavior, structure, and potential impact on health.12
Key Differences
- Invasiveness: The primary distinction is that malignant tumors are aggressive; they invade and destroy surrounding healthy tissues. In contrast, benign tumors remain localized at their site of origin and do not invade adjacent tissues.123
- Metastasis: Malignant tumors have the capacity for metastasis, meaning they can spread to distant sites in the body via the circulatory or lymphatic systems to form secondary tumors. Benign tumors do not metastasize.143
- Structure: Many benign tumors are enclosed by a protective capsule of connective tissue, which keeps them contained. Malignant tumors typically lack a true capsule, allowing them to infiltrate surrounding areas.32
- Cell Appearance: Under a microscope, malignant cells often appear more abnormal, or "anaplastic," meaning they have lost the specialized characteristics of the tissue from which they originated. Benign cells often resemble normal cells more closely.32
While benign tumors are generally less dangerous, they can still cause health issues by compressing vital structures or organs.13