Final answer:
False. Most cases of adult intussusception are not due to underlying malignancy.
Step-by-step explanation:
Most cases of adult intussusception are false. While intussusception is more common in children and is often caused by a condition called a Meckel's diverticulum, in adults it is typically caused by a structural abnormality or an underlying medical condition such as a tumor. However, malignancy is not the most common cause of adult intussusception.