A lesion is a non-specific term referring to abnormal tissue in the body. It can be caused by any disease process including trauma (physical, chemical, electrical), infection, neoplasm, metabolic and autoimmune.
Not all lesions require treatment.
Lesions can also be inflicted intentionally during surgery, for example to specific regions of the brain to treat epilepsy. In psychology, lesion means inflicting damage to an area of the brain i.e. by burning or cutting, in order to study the effects of disabling this area of the brain.
Lesion is derived from a Latin word which means "injury." Lesion: Pronounced "lee-sion" with the emphasis on the "lee," a lesion can be almost any abnormality involving any tissue or organ due to any disease or any injury.
There are, not surprisingly, many types of lesions. There are also a number of different ways of classifying and naming lesions. Lesions can, for instance, be categorized according to whether or not they are caused by cancer. A benign lesion is non-cancerous whereas a malignant lesion is cancerous. For example, a biopsy of a skin lesion may prove it to be benign or malignant, or evolving into a malignant lesion (called a premalignant lesion).
Lesions can be defined according to the patterns they form. For example, a bull's-eye or target lesion is one that looks like the bull's eye on a target. (In an X-ray of the duodenum, a bull's-eye lesion can represent a tumor with an ulcer (crater) in the center.) A coin lesion is a round shadow resembling a coin on a chest X-ray. It, too, is usually due to a tumor.
Lesions can be named for persons who first described them. For instance, a Ghon lesion (or Ghon focus) is the scar-like "signature" in the lungs of adults left by tuberculosis in childhood.
Lesions can also be categorized by their size. A gross lesion is one that can be seen with the naked eye. A microscopic or histologic lesion requires the magnification of a microscope to be seen. The basis of sickle cell disease is a molecular lesion, one that is not even visible with a microscope but is only detectable on the molecular (protein or DNA) level.
Location is another basis for naming lesions. In neurology, a central lesion involves the brain or spinal cord, i.e., the central nervous system. A peripheral lesion involves the nerves away from the spinal cord and does not involve the central nervous system.
There is a virtually endless assortment of lesions in medicine: primary lesions, secondary lesions, impaction lesions, indiscriminate lesions, irritative lesions, etc. Many are named for people including the Armanni-Ebstein lesion, a Bankart lesion, a Blumenthal lesion, and so on.
The word "lesion" comes from the Latin noun "laesio" meaning "an attack or injury" which is related in Latin to the verb "laedere" = "to hurt, strike or wound."
The content of this page is retrieved from http://en.wikipedia.org/wiki/Lesion under GFDL
