IDLEs meaning in Medical ?

A benign tumor is a mass of cells (tumor) that lacks the ability to either invade neighboring tissue or metastasize (spread throughout the body). When removed, benign tumors usually do not grow back, whereas malignant tumors sometimes do. Unlike most benign tumors elsewhere in the body, benign brain tumors can be life-threatening. Benign tumors generally have a slower growth rate than malignant tumors and the tumor cells are usually more differentiated (cells have more normal features). They are typically surrounded by an outer surface (fibrous sheath of connective tissue) or stay contained within the epithelium. Common examples of benign tumors include moles and uterine fibroids.

Although benign tumors will not metastasize or locally invade tissues, some types may still produce negative health effects. The growth of benign tumors produces a "mass effect" that can compress tissues and may cause nerve damage, reduction of blood flow to an area of the body (ischaemia), tissue death (necrosis) and organ damage. The health effects of the tumor may be more prominent if the tumor is within an enclosed space such as the cranium, respiratory tract, sinus or inside bones. Tumors of endocrine tissues may overproduce certain hormones. Examples include thyroid adenomas and adrenocortical adenomas.

Although most benign tumors are not life-threatening, many types of benign tumors have the potential to become cancerous (malignant) through a process known as tumor progression. For this reason and other possible negative health effects, some benign tumors are removed by surgery.