Lesion

A lesion is any damage or unusual change in the tissue of an organism, usually from an injury or a disease. The word lesion comes from the Latin word laesio, meaning "injury." Lesions can happen in both plants and animals.

Lesions help scientists and doctors learn what is wrong when something is not working well in a body or a plant. By studying lesions, experts can find out about different diseases and how injuries change living things.

In animals, lesions might look like a sore, a bump, or a change in skin color. In plants, they might look like brown spots or areas that do not grow properly. These changes can show us a lot about the health of the organism.

Types

Lesions are changes or damage in body tissues, often caused by injury or disease. They can happen anywhere in the body and come in many forms.

For example, lesions in the lungs from tuberculosis are called Ghon lesions, and skin lesions from the varicella zoster virus cause chickenpox. Dental caries, also known as cavities, are lesions in the teeth.

Lesions can be grouped by where they occur, such as in the skin or brain. Some are named after the part of the body they affect, like a brain lesion or a lesion in the heart muscle. They can also be described by their cause, size, and shape. Some lesions are visible to the naked eye, while others need a microscope. Others might look like a coin on an X-ray or have a bullseye shape.

Research using lesions

Brain lesions help scientists learn how the brain works. By looking at how damage in certain areas changes thinking and memory, researchers can understand what those parts of the brain normally do. This research is based on two ideas: different parts of the brain control different functions, and parts of the brain that are not damaged still work normally.

Scientists sometimes use special control tests called "sham lesions" to compare results. In these tests, they set up the equipment as if they were going to create a lesion, but they don’t actually damage the brain tissue. When studying humans, it can be difficult to find people with damage in the exact brain area scientists want to study, so they often use a technique called transcranial magnetic stimulation to temporarily mimic lesion effects. With animals, scientists can carefully create lesions in specific areas, such as the hippocampus in rats, to learn more about how those parts help with memory and recognizing objects.

Notable lesions

Lesions are changes or damage in body tissues that can happen because of injury or sickness. There are many types of lesions that can occur in different parts of the body.

Some common lesions include:

• Soft-tissue lesions: Morel-Lavallee lesion, Bankart lesion, Perthes Lesion, Stener lesion, SLAP lesion
• Diabetes-associated lesions: Armanni-Ebstein lesion, Blumenthal lesion
• Bone lesions: Non-ossifying fibroma, ALPSA lesion, Hill–Sachs lesion, Osteoporosis circumscripta, Osteolytic lesion
• Brain lesions: Olney's lesions
• Skin lesions: Melanocytic nevus, Skip lesion, Osler's node, Keratoderma blennorrhagicum, Dermatosis papulosa nigra, Leukemid, Janeway lesion, Kaposi's sarcoma, Nevus spilus, Chronic scar keratosis
• Gastrointestinal lesions: Dieulafoy's lesion, Cameron lesions
• Endodermal lesions: Melanocytic oral lesion, Endometrial intraepithelial neoplasia
• Other disease-associated lesions: Ghon focus, Benign lymphoepithelial lesion, Multiple sclerosis lesions, Herpes labialis, Tropical ulcer, Herpetic whitlow