lesion

Lesion is any abnormality in the tissue of an organism, usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.

Because the definition of a lesion is so broad, the varieties of lesions are virtually endless. They are subsequently classified by their features.

If a lesion is caused by a tumor it will be classified as malignant versus benign. Lesions may be classified by the shape they form, as is the case with many ulcers, which can have a bullseye or 'target' appearance. Their size may be specified as gross or histologic depending on whether they are visible to the unaided eye or require a microscope to see.

Lesions are often classified by their location. For example, a 'skin lesion' or a 'brain lesion'.

Lesions are caused by any process that damages tissues. lesion causes epilepcy Lesions can also be caused by metabolic processes, like an ulcer or autoimmune activity, as in the case with many forms of arthritis.

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