Final answer:
The main difference is that benign (nonmalignant) tumors remain localized and do not spread, while malignant tumors are cancerous, invasive, and can metastasize to other parts of the body.
Step-by-step explanation:
Main Difference Between Malignant and Nonmalignant Tumors
The main difference between malignant and nonmalignant tumors lies in their growth and spread. A nonmalignant tumor, also known as a benign tumor, remains localized within its original site. It does not invade neighboring tissues or spread to other parts of the body, and generally, it does not pose a significant health risk. On the other hand, a malignant tumor is cancerous and has the potential to grow uncontrollably and invade surrounding tissues. Importantly, malignant tumors may undergo a process called metastasis, where cancerous cells break away, enter the bloodstream, and form new tumors in different parts of the body.
Cancerous cells in malignant tumors are characterized by their ability to escape the normal control system of the body. This unchecked proliferation and lack of apoptosis, or programmed cell death, leads to the formation of a mass of abnormal cells. While the immune system may sometimes destroy these cancerous cells, those that remain undetected can form a malignant tumor. In contrast, benign tumors do not invade other tissues or metastasize, and they can often be easily removed without significant health consequences.