A melanocytic nevus is usually a noncancerous condition of pigment-producing skin cells. It is a type of melanocytic tumor that contains nevus cells. Some sources equate the term mole with "melanocytic nevus", but there are also sources that equate the term mole with any nevus form.
Melanoma, also redundantly known as malignant melanoma, is a type of cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye. In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness, or skin breakdown.
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 an aggressive type of skin cancer. Melanoma is a group of serious skin cancers that arise from pigment cells (melanocytes); acral lentiginous melanoma is a kind of lentiginous skin melanoma. Acral lentiginous melanoma is the most common subtype in people with darker skins and is rare in people with lighter skin types. It is not caused by exposure to sunlight or UV radiation, and wearing sunscreen does not protect against it. Acral lentiginous melanoma is commonly found on the palms, soles, under the nails, and in the oral mucosa. It occurs on non-hair-bearing surfaces of the body, which have not necessarily been exposed to sunlight. It is also found on mucous membranes.
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. There are four main types of skin biopsies: shave biopsy, punch biopsy, excisional biopsy, and incisional biopsy. The choice of the different skin biopsies is dependent on the suspected diagnosis of the skin lesion. Like most biopsies, patient consent and anesthesia are prerequisites.
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.
Oral pigmentation is asymptomatic and does not usually cause any alteration to the texture or thickness of the affected area. The colour can be uniform or speckled and can appear solitary or as multiple lesions. Depending on the site, depth, and quantity of pigment, the appearance can vary considerably.
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.
