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.
Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye. In women, melanomas most commonly occur on the legs; while in men, on the back. Melanoma is frequently referred to as malignant melanoma. However, the medical community stresses that there is no such thing as a 'benign melanoma' and recommends that the term 'malignant melanoma' should be avoided as redundant.
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.
Acral lentiginous melanoma is a type of skin cancer. It typically begins as a uniform brownish mark before becoming darker and wider with a blurred irregular edge, most frequently seen in the foot of a person with darker skin. It may become bumpy and ulcerate. Just under the nail it typically appears as dark longitudinal streaks, and it may spread.
A seborrheic keratosis is a non-cancerous (benign) skin tumour that originates from cells, namely keratinocytes, in the outer layer of the skin called the epidermis. Like liver spots, seborrheic keratoses are seen more often as people age.
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.
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.
Ocular melanosis (OM) is a blue-gray and/or brown lesion of the conjunctiva that can be separated into benign conjunctival epithelial melanosis (BCEM) and primary acquired melanosis (PAM), of which the latter is considered a risk factor for uveal melanoma. The disease is caused by an increase of melanocytes in the iris, choroid, and surrounding structures. Overproduction of pigment by these cells can block the trabecular meshwork through which fluid drains from the eye. The increased fluid in the eye leads to increased pressure, which can lead to glaucoma. In humans, this is sometimes known as pigment dispersion syndrome.
Lentigo maligna melanoma is a melanoma that has evolved from a lentigo maligna, as seen as a lentigo maligna with melanoma cells invading below the boundaries of the epidermis. They are usually found on chronically sun damaged skin such as the face and the forearms of the elderly.
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.
The congenital melanocytic nevus is a type of melanocytic nevus found in infants at birth. This type of birthmark occurs in an estimated 1% of infants worldwide; it is located in the area of the head and neck 15% of the time.
Dermatoscopy, also known as dermoscopy or epiluminescence microscopy, is the examination of skin lesions with a dermatoscope. It is a tool similar to a camera to allow for inspection of skin lesions unobstructed by skin surface reflections. The dermatoscope consists of a magnifier, a light source, a transparent plate and sometimes a liquid medium between the instrument and the skin. The dermatoscope is often handheld, although there are stationary cameras allowing the capture of whole body images in a single shot. When the images or video clips are digitally captured or processed, the instrument can be referred to as a digital epiluminescence dermatoscope. The image is then analyzed automatically and given a score indicating how dangerous it is. This technique is useful to dermatologists and skin cancer practitioners in distinguishing benign from malignant (cancerous) lesions, especially in the diagnosis of melanoma.
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).
Melanocytic tumors of uncertain malignant potential (MELTUMP) are melanocytic lesions in the dermis that cannot be classified by morphology as either benign naevi (moles) or malignant melanomas because the mass shows features of both.
A blue nevus is a type of coloured mole, typically a single well-defined blue-black bump.
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.
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.
Pseudomelanoma is a cutaneous condition in which melanotic skin lesions clinically resemble a superficial spreading melanoma at the site of a recent shave removal of a melanocytic nevus.
A nevoid melanoma is a malignant neoplastic lesion of the skin. It is a type of melanoma, the most dangerous form of skin cancer. Nevoid melanomas are clinically significant because they are difficult to distinguish from a benign nevus of the skin, which requires no treatment and is common on most individuals. Nevoid morphologies represent up to 3% of all cases of melanoma.
Animal-type melanoma is a rare subtype of melanoma that is characterized by heavily pigmented dermal epithelioid and spindled melanocytes. Animal-type melanoma is also known to be called equine-type melanoma, pigment synthesizing melanoma, and pigmented epithelioid melanocytoma (PEM). While melanoma is known as the most aggressive skin cancer, the mortality for PEM is lower than in other melanoma types. Animal-type melanoma earned its name due to the resemblance of melanocytic tumors in grey horses.
