Dermatology & Skin Cancer Glossary

A widely adopted clinical mnemonic (Asymmetry, Border, Color, Diameter, Evolution) formulated by New York University to help patients and clinicians identify early warning signs of cutaneous melanoma.

A rare, aggressive subtype of melanoma that occurs on non-hair-bearing, sun-protected skin surfaces such as the palms of the hands, soles of the feet, and underneath fingernails or toenails (subungual).

An atypical melanoma subtype that produces little to no brown or black melanin pigment, presenting as a pink, red, or skin-colored papule or nodule, making early visual detection more challenging.

A benign melanocytic nevus exhibiting irregular borders, color variation, and asymmetric contours under clinical examination, associated with an increased lifetime statistical risk of melanoma.

The most common form of skin cancer arising from the basal cells of the deepest epidermal layer, typically presenting as a pearly, translucent bump with visible tiny blood vessels (telangiectasias).

A minor in-office surgical procedure where a dermatologist removes a partial (shave/punch) or complete (excisional) skin tissue specimen for microscopic histopathological examination.

A fundamental prognostic measurement in melanoma staging, measuring the precise vertical thickness of tumor invasion from the top of the granular layer of the epidermis down to the deepest point of tumor penetration in millimeters.

Another clinical name for a cherry angioma - a harmless, benign proliferation of small capillary blood vessels that appears as a bright red or ruby papule on the skin.

A common, benign vascular skin growth consisting of clusters of dilated capillaries, often appearing on the trunk and limbs of adults over age 30.

An anatomical staging scale (Levels I to V) describing the specific anatomical skin layers (epidermis, papillary dermis, reticular dermis, subcutaneous fat) invaded by melanoma cells.

Apple's local machine learning framework that enables mobile apps like Mole Tracker to execute deep neural network visual analysis directly on the device processor without transmitting private health photos across the internet.

A cutaneous melanoma that develops spontaneously on previously unblemished skin where no pre-existing mole was located (accounting for 70% to 80% of all melanoma cases).

A licensed medical doctor (MD or DO) who has completed specialized residency training in the diagnosis, medical treatment, and surgical management of diseases of the skin, hair, nails, and cutaneous malignancies.

A specialized handheld medical instrument utilizing high-quality magnification and cross-polarized illumination to eliminate surface skin reflection, revealing deep pigmentary and vascular architecture.

A genetic condition characterized by having more than 50 to 100 total body moles, including numerous large, clinically atypical nevi, conferring a significantly elevated risk for cutaneous melanoma.

Small, flat, light-brown spots that appear on sun-exposed skin in genetically predisposed individuals, darkening in response to UV radiation during summer and fading in winter.

The dark brown-to-black form of melanin pigment produced by melanocytes that absorbs and scatters ultraviolet radiation, providing superior natural photoprotection compared to pheomelanin.

A diagnostic procedure where the entire suspicious skin lesion is excised along with a narrow margin of normal surrounding skin to provide complete architectural context for the dermatopathologist.

A clinical classification system formulated in 1975 by Dr. Thomas Fitzpatrick dividing human skin into six phototypes (I to VI) based on constitutional melanin pigmentation and erythema reaction to UV radiation.

The microscopic analysis of biological tissue samples by a pathologist to identify cellular atypia, architectural disorder, mitotic rate, and confirm malignant or benign diagnoses.

A flat, uniformly pigmented mole where the proliferating melanocyte nests are located strictly along the dermo-epidermal junction between the epidermis and dermis.

An early, in situ subtype of melanoma that develops primarily on chronically sun-damaged facial skin of older adults, often resembling an irregular, slowly enlarging brown sunspot.

The natural biological pigment produced within melanosomes by melanocyte cells that determines skin, hair, and eye color and shields cellular DNA from ultraviolet radiation.

A specialized dendrite-bearing cell located in the basal layer of the epidermis responsible for synthesizing melanin pigment through the biochemical process of melanogenesis.

The most serious and aggressive primary malignancy of the skin, originating from malignant transformation of melanocytes and carrying a high potential for lymphatic and hematogenous metastasis if not caught early.

The lowest threshold dose of ultraviolet radiation that produces perceptible, uniform redness (erythema) with well-defined borders on unprotected human skin 24 hours post-exposure.

The formal medical and dermatological term for a common mole or circumscribed, stable collection of melanocytes.

A yellow-to-reddish sulfur-containing melanin pigment prevalent in individuals with red hair and fair skin (Fitzpatrick Type I) that generates phototoxic free radicals upon UV exposure.

An optical technique using cross-polarized filters to visualize deeper dermal collagen and crystalline structures (such as shiny white streaks in melanoma) without requiring liquid immersion.

An extremely common, non-cancerous benign skin growth that often appears 'stuck on' the skin like candle wax or velvet, ranging from light tan to deep black.

A benign, flat, dark spot caused by localized melanocyte hyperproliferation from cumulative lifetime ultraviolet radiation, common on hands and face.

The second most common form of skin cancer arising from keratinocytes in the squamous stratum of the epidermis, typically appearing as a firm red nodule or crusted ulcer.

A form of acral melanoma developing within the nail matrix, presenting as a dark longitudinal brown or black band underneath the fingernail or toenail (Hutchinson's sign).

The delivery of dermatologic clinical consultations, triage, and photographic timeline monitoring via telecommunications and secure digital health applications.

A clinical observational principle stating that an outlier mole that looks visibly different in color, size, or shape from all of a patient's other typical moles is significantly more likely to be malignant.

An international standard measurement developed by the WHO indicating the daily peak strength of sunburn-producing solar ultraviolet radiation on a scale from 1 (Low) to 11+ (Extreme).