How do malignant neoplasms differ from benign tumors?

Malignant neoplasms are characterized by their ability to metastasize, or spread to other parts of the body beyond their original site. This capability is one of the defining features that distinguishes malignant tumors from benign ones. When cancerous cells break away from the primary tumor, they can travel through the bloodstream or lymphatic system to establish new tumors in distant organs or tissues. This invasive growth pattern is a significant concern in oncology, as it contributes to the progression and severity of cancer.

In contrast, benign tumors typically remain localized and do not have the ability to invade nearby tissues or spread to other parts of the body. They usually grow more slowly than malignant tumors and can often be removed surgically with a lower risk of recurrence. While size can vary between malignant and benign tumors, size alone is not a reliable indicator of malignancy. Therefore, the ability to metastasize serves as a critical distinguishing factor between these two types of neoplasms, making it the correct choice in this context.