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.
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.
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.
A dysplastic nevus or atypical mole is a nevus (mole) whose appearance is different from that of common moles. In 1992, the NIH recommended that the term "dysplastic nevus" be avoided in favor of the term "atypical mole". An atypical mole may also be referred to as an atypical melanocytic nevus, atypical nevus, B-K mole, Clark's nevus, dysplastic melanocytic nevus, or nevus with architectural disorder.
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.
Nodular melanoma (NM) is the most aggressive form of melanoma. It tends to grow more rapidly in thickness than in diameter compared to other melanoma subtypes. Instead of arising from a pre-existing mole, it may appear in a spot where a lesion did not previously exist. Since NM tends to grow in depth more quickly than it does in width, and can occur in a place that did not have a previous lesion, the prognosis is often worse because it takes longer for a person to be aware of the changes. NM is most often darkly pigmented; however, some NM lesions can be light brown, multicolored or even colorless (non-pigmented). A light-colored or non-pigmented NM lesion may escape detection because the appearance is not alarming, however an ulcerated and/or bleeding lesion is common. Polypoid melanoma is a virulent variant of nodular melanoma.
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.
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.
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).
A blue nevus is a type of coloured mole, typically a single well-defined blue-black bump.
A Spitz nevus is a benign skin lesion. A type of melanocytic nevus, it affects the epidermis and dermis.
Nevus spilus, also known as speckled lentiginous nevus, is a light brown or tan birth mark, speckled with small, dark spots or small bumps. If it occurs in a segmental pattern then it is sometimes referred to as a Zosteriform speckled lentiginous nevus.
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.
Balloon cell nevus is a benign nevus. It appears like 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.
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.
Choroidal nevus is a type of eye neoplasm that is classified under choroidal tumors as a type of benign (non-cancerous) melanocytic tumor. A choroidal nevus can be described as an unambiguous pigmented blue or green-gray choroidal lesion, found at the front of the eye, around the iris, or the rear end of the eye.
