Melanocytic nevus overview
|
Melanocytic nevus Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Melanocytic nevus overview On the Web |
|
American Roentgen Ray Society Images of Melanocytic nevus overview |
|
Risk calculators and risk factors for Melanocytic nevus overview |
Editors-In-Chief: Martin I. Newman, M.D., FACS, Cleveland Clinic Florida, [1]; Michel C. Samson, M.D., FRCSC, FACS [2]
Overview
A mole, technically known as a melanocytic nevus, is a small, dark spot on human skin. According to the American Academy of Dermatology, the majority of moles appear during the first two decades of a person’s life while about one in every 100 babies are born with moles. Acquired moles are a form of benign neoplasm, while congenitalmoles are considered a minor malformation, or hamartoma. A mole can be either subdermal (composed of melanin), or a pigmented growth on the skin, formed mostly of a type of cell known as melanocytes. 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.
Historical Perspective
At one time in the 1950s and 60s, (and, to lesser extent, currently) a mole was known as a “beauty mark” when it appeared in certain spots on a woman’s face. Examples include Marilyn Monroe, model Cindy Crawford and singer Madonna. Madonna's facial mole -- below her right nostril -- has been surgically removed.
Classification
Melanocytic nevus is a type of melanocytic lesion. Depending on the degree of cytologic atypia it can be classified into mild, moderate or severe.
Pathophysiology
Melanocytic nevus is a benign growth on the skin (usually tan, brown, or flesh-colored) that contains a cluster of melanocytes and surrounding supportive tissue.
Causes
Scientists suspect that overexposure to ultraviolet light, including excessive sunlight, may play a role in the formation of acquired moles.[1] However, more research is needed in this area.
Differentiating Melanocytic Nevus from Other Diseases
Melanocytic nevus must be differentiate from dysplastic nevus, melanoma and epidermal nevus.
Epidemiology and Demographics
Darker skin shades tend to have fewer moles compared to fair complexion.
Risk Factors
Most important risk factor for melanocytic nevus is sunlight however, genetic predisposition is an important factor as well.
Natural History, Complications, and Prognosis
Vast majority of moles are benign. Nonetheless, the National (U.S.) Cancer Institute reported 59,940 new cases of melanoma by June, 2007, with 8,110 deaths.[2]
Diagnosis
Diagnostic Study of Choice
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
X-ray
Echocardiography and Ultrasound
CT scan
MRI
Other Imaging Findings
Other Diagnostic Studies
Medical Therapy
Surgery
If a mole is highly suspicious of being a melanoma, then it might need to be removed and biopsied (microscopic evaluation by a pathologist). Other reasons for removal may be cosmetic, or because a raised mole interferes with daily living (e.g. shaving).
Moles can be removed by laser, surgery or electrocautery. They leave a red mark on the site which morphs back to the patient’s usual skin color in about two weeks. However, there might still be a risk of spread of the melanoma, so the methods of Melanoma diagnosis, including e.g. excitional biopsy.
References
- ↑ Arne van Schanke, Gemma M.C.A.L. van Venrooij, Marjan J. Jongsma, H. Alexander Banus, Leon H.F. Mullenders, Henk J. van Kranen and Frank R. de Gruijl. Induction of Nevi and Skin Tumors in Ink4a/ArfXpa Knockout Mice by Neonatial, Intermittent, or Chronic UVB Exposures. Cancer Res 2006; 66 (5), 2608-15.
- ↑ http://www.nci.nih.gov/cancertopics/types/melanoma