Lesion

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Lesion
Specialty Pathology

A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. Lesion is derived from the Latin laesio meaning "injury". [1] Lesions may occur in plants as well as animals.

Contents

Types

There is no designated classification or naming convention for lesions. Since lesions can occur anywhere in the body and the definition of a lesion is so broad, the varieties of lesions are virtually endless. Generally, lesions may be classified by their patterns, their sizes, their locations, or their causes. They can also be named after the person who discovered them. For example, Ghon lesions, which are found in the lungs of those with tuberculosis, are named after the lesion's discoverer, Anton Ghon. [1] The characteristic skin lesions of a varicella zoster virus infection are called chickenpox . Lesions of the teeth are usually called dental caries, or "cavities".

Location

Lesions are often classified by their tissue types or locations. For example, a "skin lesion" or a "brain lesion" are named for the tissue where they are found. 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 lesion in the peripheral nervous system is called a peripheral lesion. [1] A myocardial lesion results from damage to the heart muscle, and a coronary lesion is a subtype that describes a lesion in the coronary arteries. Coronary lesions are then further classified according to the side of the heart that is affected and the diameter of the artery in which they form. [2]

Cause and behavior

If a lesion is caused by a tumor, it can be classified as malignant or benign after analysis of a biopsy. A benign lesion that is evolving into a malignant lesion is called "premalignant". [1] Cancerous lesions are sometimes classified by their growth kinetics, such as the Lodwick classification, which characterizes classes of bone lesions. [3] Another type is an excitotoxic lesion, which can be caused by excitatory amino acids like kainic acid that kill neurons through overstimulation.

Size and shape

Lesion size may be specified as gross, meaning it is visible to the unaided eye, or histologic , meaning a microscope is needed to see it. [4] [5] A space-occupying lesion, as the name suggests, has a recognizable volume and may impinge on nearby structures, whereas a non space-occupying lesion is simply a hole in the tissue, e.g. a small area of the brain that has turned to fluid following a stroke. [1]

Lesions may also be classified by the shape they form. This is the case with many ulcers, which can have a bullseye or 'target' appearance. A coin lesion as seen in an X-ray has the appearance of a coin sitting on the patient's chest. [1]

Research using lesions

Brain lesions may help researchers understand brain function. Research involving lesions relies on two assumptions: that brain damage can affect different aspects of cognition independently, and that a locally damaged brain functions identically to a normal brain in its "undamaged" parts. [6]

Sham lesion is the name given to a control procedure during a lesion experiment. In a sham lesion, an animal may be placed in a stereotaxic apparatus and electrodes inserted as in the experimental condition, but no current is passed, and therefore damage to the tissue should be minimal.

Research with humans

Humans with brain lesions are often the subjects of research with the goal of establishing the function of the area where their lesion occurred. [7]

A drawback to the use of human subjects is the difficulty in finding subjects who have a lesion to the area the researcher wishes to study. As such, transcranial magnetic stimulation is often used in cognition and neuroscience-related tests to imitate the effect. [8]

Research with animals

Using animal subjects gives researchers the ability to study lesions in specific body parts of the subjects, allowing them to quickly acquire a large group of subjects. An example of such a study is the lesioning of rat hippocampi to establish the role of the hippocampus in object recognition and object recency. [9]

Notable lesions

Soft-tissue lesions

Diabetes-associated lesions

Bone lesions

Brain lesions

Skin lesions

Gastrointestinal lesions

Endodermal lesions

Misc. disease-associated lesions

See also

Related Research Articles

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A melanocytic nevus is usually a noncancerous condition of pigment-producing skin cells. It is a type of melanocytic tumor that contains nevus cells. A mole can be either subdermal or a pigmented growth on the skin, formed mostly of a type of cell known as a melanocyte. The high concentration of the body's pigmenting agent, melanin, is responsible for their dark color. Moles are a member of the family of skin lesions known as nevi, occurring commonly in humans. Some sources equate the term "mole" with "melanocytic nevus", but there are also sources that equate the term "mole" with any nevus form.

<span class="mw-page-title-main">Nevus</span> Mole or birthmark; visible, circumscribed, chronic skin lesion

Nevus is a nonspecific medical term for a visible, circumscribed, chronic lesion of the skin or mucosa. The term originates from nævus, which is Latin for "birthmark"; however, a nevus can be either congenital or acquired. Common terms, including mole, birthmark, and beauty mark, are used to describe nevi, but these terms do not distinguish specific types of nevi from one another.

<span class="mw-page-title-main">Benign tumor</span> Mass of cells which cannot spread throughout the body

A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize. Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have relatively well differentiated cells. They are often surrounded by an outer surface or stay contained within the epithelium. Common examples of benign tumors include moles and uterine fibroids.

<span class="mw-page-title-main">Superficial spreading melanoma</span> Medical condition

Superficial spreading melanoma (SSM) is a type of skin cancer that typically starts as an irregularly edged dark spot typically on sun-exposed part of the body. The colour may be variable with dark, light and reddish shades; occasionally no color at all. It typically grows in diameter before spreading to deeper tissue, forming a bump or becoming an ulcer. Itching, bleeding and crust formation may occur in some. The backs and shoulders of males and legs of women are particularly prone.

<span class="mw-page-title-main">Dysplastic nevus</span> Mole in the skin with an abnormal appearance

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<span class="mw-page-title-main">Dysplastic nevus syndrome</span> Medical condition

Dysplastic nevus syndrome, also known as familial atypical multiple mole–melanoma (FAMMM) syndrome, is an inherited cutaneous condition described in certain families, and characterized by unusual nevi and multiple inherited melanomas. First described in 1820, the condition is inherited in an autosomal dominant pattern, and caused by mutations in the CDKN2A gene. In addition to melanoma, individuals with the condition are at increased risk for pancreatic cancer.

<span class="mw-page-title-main">Lentigo maligna</span> Medical condition

Lentigo maligna is where melanocyte cells have become malignant and grow continuously along the stratum basale of the skin, but have not invaded below the epidermis. Lentigo maligna is not the same as lentigo maligna melanoma, as detailed below. It typically progresses very slowly and can remain in a non-invasive form for years.

<span class="mw-page-title-main">Congenital melanocytic nevus</span> Congenital mole caused by genetic mutations

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<span class="mw-page-title-main">Becker's nevus</span> Irregularly pigmented area of skin with hair growth

Becker's nevus is a benign skin disorder predominantly affecting males. The nevus can be present at birth, but more often shows up around puberty. It generally first appears as an irregular pigmentation on the torso or upper arm, and gradually enlarges irregularly, becoming thickened and often hairy (hypertrichosis). The nevus is due to an overgrowth of the epidermis, pigment cells (melanocytes), and hair follicles. This form of nevus was first documented in 1948 by American dermatologist Samuel William Becker (1894–1964).

Epithelioid may refer to:

<span class="mw-page-title-main">Granular cell tumor</span> Medical condition

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<span class="mw-page-title-main">Blue nevus</span> Type of melanocytic tumor

A blue nevus is a type of coloured mole, typically a single well-defined blue-black bump.

<span class="mw-page-title-main">Skin biopsy</span> Removal of skin cells for medical examination

Skin biopsy is a biopsy technique in which a skin lesion is removed to be sent to a pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin biopsies are also done by family physicians, internists, surgeons, and other specialties. However, performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited, and therefore doctors and patients may forgo traditional biopsy techniques and instead choose Mohs surgery.

<span class="mw-page-title-main">Spitz nevus</span> Benign skin tumor

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<span class="mw-page-title-main">Benign melanocytic nevus</span> Medical condition

A benign melanocytic nevus is a cutaneous condition characterised by well-circumscribed, pigmented, round or ovoid lesions, generally measuring from 2 to 6 mm in diameter. A benign melanocytic nevus may feature hair or pigmentation as well.

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<span class="mw-page-title-main">Palisaded encapsulated neuroma</span> Medical condition

Palisaded encapsulated neuroma (PEN) is a rare, benign cutaneous condition characterized by small, firm, non-pigmented nodules or papules. They typically occur as a solitary (single) lesion near the mucocutaneous junction of the skin of the face, although they can occur elsewhere on the body.

Vulvar tumors are those neoplasms of the vulva. Vulvar and vaginal neoplasms make up a small percentage (3%) of female genital cancers. They can be benign or malignant. Vulvar neoplasms are divided into cystic or solid lesions and other mixed types. Vulvar cancers are those malignant neoplasms that originate from vulvar epithelium, while vulvar sarcomas develop from non-epithelial cells such as bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Epithelial and mesenchymal tissue are the origin of vulvar tumors.

<span class="mw-page-title-main">Melanocytoma</span>

A melanocytoma is a rare pigmented tumor that has been described as a variant of the melanocytic nevus and is derived from the neural crest. The term "melanocytoma" was introduced by Limas and Tio in 1972.

References

  1. 1 2 3 4 5 6 "Lesion...What Does The Doctor Mean?". MedicineNet. Retrieved 2016-03-03.[ dead link ]
  2. ↑ Farooq, Vasim; Brugaletta, Salvatore; Serruys, Patrick W. (2011-12-01). "Contemporary and evolving risk scoring algorithms for percutaneous coronary intervention". Heart. 97 (23): 1902–1913. doi:10.1136/heartjnl-2011-300718. ISSN   1468-201X. PMID   22058284. S2CID   23254704.
  3. ↑ Bennett, D. Lee; El-Khoury, Georges H. (6 May 2004). "General approach to lytic bone lesions". Appliedradiology.com. Retrieved 2016-03-03.
  4. ↑ Leeson, Thomas S.; Leeson, C. Roland (1981). Histology (Fourth ed.). W. B. Saunders Company. p. 600. ISBN   978-0-7216-5704-2.
  5. ↑ Stedman's medical dictionary (27th ed.). Lippincott Williams & Wilkins. 2006. ISBN   068340007X.
  6. ↑ Kosslyn, Stephen M.; Intriligator, James M. (1992). "Is Cognitive Neuropsychology Plausible? The Perils of Sitting on a Juan-Legged Stool". Journal of Cognitive Neuroscience. 4 (1): 96–105. doi:10.1162/jocn.1992.4.1.96. PMID   23967860. S2CID   15557071.
  7. ↑ Adolphs, Ralph (2016-06-15). "Human Lesion Studies in the 21st Century". Neuron. 90 (6). Pubmed Central: 1151–1153. doi:10.1016/j.neuron.2016.05.014. PMC   5656290 . PMID   27311080.
  8. ↑ Sliwinska, M. W., Vitello, S., & Devlin, J. T. (2014). Transcranial magnetic stimulation for investigating causal brain-behavioral relationships and their time course. Journal of visualized experiments : JoVE, (89), 51735. doi : 10.3791/51735
  9. ↑ Albasser, Amin, Lin, Iordanova, Aggelton. Evidence That the Rat Hippocampus Has Contrasting Roles in Object Recognition Memory and Object Recency Memory
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