Lesion

Lesion
Classification and external resources
Specialty	Pathology
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A lesion is any abnormal damage or change in the tissue of an organism, usually caused by disease or trauma. Lesion is derived from the Latin word laesio meaning injury. Lesions may occur in plants as well as animals.

There is no designated classification or naming convention for lesions. Because the definition of a lesion is so broad, the varieties of lesions are virtually endless. Lesions can occur anywhere in the body that consists of soft tissue or osseous matter, though most frequently found in the mouth, skin, and the brain, or anywhere where a tumor may occur.

Generally, lesions may be classified by the patterns they form, their size, their location, or their cause. Lesions are sometimes also named after the person who discovered them. Some lesions have specialized names, such as Ghon lesions in the lungs of tuberculosis victims, which is named after the lesion's discoverer. The characteristic skin lesions of a varicella zoster virus (VZV) infection are called chickenpox. Lesions of the teeth are usually called dental caries.

Lesions are often classified by their tissue type or location. For example, a "skin lesion" or a "brain lesion" are named for the tissue they are found in. If there is an added significance to regions within the tissue - such as in neural injuries where different locations correspond to different neurological deficits - they are further classified by location. For example, a lesion in the central nervous system is called a central lesion, and a peripheral lesion is one located in the peripheral nervous system. A myocardial lesion results from damage to the heart muscle, and a coronary lesion is a subtype that specifically describes a lesion in the coronary arteries. Coronary lesions are then further classified by the side of the heart that is affected, and diameter of the artery in which they form.

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