Which feature distinguishes malignant tumors from benign ones?

• A. They stay localized
• B. They can metastasize
• C. They are always red
• D. They are painless

Answer: (B)

The key difference is the ability to spread beyond the original site. Malignant tumors have cells that invade nearby tissues and can travel through blood or lymphatic vessels to establish new tumors in distant parts of the body. This metastatic potential is what makes them dangerous and is the defining feature that sets malignant growths apart from benign ones, which grow locally and stay confined. Color or pain isn’t a reliable indicator and can vary; some tumors are not obviously red, and pain can occur with both benign and malignant growths depending on location and size. So, metastasis—the spread to distant sites—is the distinguishing trait.