Melanocytic Nevus (Mole) ICD-10: D22.9

Benign skin lesion / Pigmented lesion

Often searched as: mole on skin, brown spot on skin, mole that changed, new mole appeared, is my mole dangerous, mole that itches, dark spot on skin, mole with irregular edges…

Clinical urgency level

lowmediumhigh

Systems Affected

skin

Severity Levels

mild

Stable, symmetric, uniform-colored mole present for years with no changes — essentially no risk, monitoring sufficient.

moderate

Atypical or dysplastic nevus — irregular borders, uneven color, or larger than 6mm; warrants dermatologist evaluation and possible biopsy.

severe

Mole with rapid change in size, shape, color, bleeding, or ulceration — must be evaluated urgently to rule out melanoma transformation.

Red Flags

A mole that grows rapidly over weeks or months
Uneven or multiple colors within a single mole (brown, black, pink, red, white)
Irregular, jagged, or blurry borders
Mole larger than 6mm (about the size of a pencil eraser)
A mole that itches, bleeds, or crusts without injury
A new dark mole appearing after age 40

Clinical Presentation

Common benign melanocytic nevus (mole) on the back

Source: Wikimedia Commons (CC BY-SA 3.0 )

Melanocytic nevus / mole image gallery — DermNet NZ

View gallery on DermNet NZ (image gallery reference)

When to See a Doctor

See a dermatologist if any mole changes in size, shape, or color, starts to itch, bleed, or crust, or if a new dark spot appears on your skin — especially if you're over 40. Annual full-body skin checks are recommended for people with many moles, fair skin, or a personal or family history of melanoma.

Differential Diagnosis

Melanoma (most important — must be ruled out for changing nevi)
Seborrheic keratosis (stuck-on waxy appearance)
Dermatofibroma (firm, slightly indented lesion)
Blue nevus (blue-gray pigmentation)
Spitz nevus (pink or reddish, often in children)
Pigmented basal cell carcinoma
Café-au-lait macule (flat light brown patch)

Comorbidities

Dysplastic nevus syndrome (familial atypical mole syndrome)
Personal or family history of melanoma
Xeroderma pigmentosum (rare genetic UV repair disorder)
Immunosuppression (higher risk of malignant transformation)

Prognosis

The vast majority of moles are benign and never become cancerous. Dysplastic (atypical) nevi have a slightly elevated risk of transformation, but even these are usually removed preventively with excellent outcomes. The overall risk of any single mole turning into melanoma is very low. However, people with more than 50 moles, dysplastic nevi, or a family history of melanoma have a meaningfully elevated lifetime melanoma risk and should have regular dermatological surveillance.

Detailed Overview

Causes, Symptoms, and When to Take Action A melanocytic nevus (often called a mole or papilloma nevus when it is raised or papillomatous) is a benign skin lesion composed of melanocytes. They vary widely in size, color, shape, and clinical significance. How It Looks Texture: Can be flat (macules), slightly raised, or papillomatous (raised with little bumps) Color: Tan, brown, dark brown; may be lighter or more pigmented depending on location and skin tone Shape: Usually round or oval, with well-defined edges; asymmetry or irregular borders are warning signs Location: Can appear anywhere on the skin; often on trunk, limbs, face; multiple nevi often present Why Does It Appear? Melanocytic nevi develop due to proliferation of melanocytes, cells that produce pigment in the skin Genetic background plays a role in number, appearance, and behavior of nevi Environmental factors like sun exposure influence their appearance, pigmentation, and risk of changes over time Should You Be Concerned? Most nevi are harmless and pose no health risk Concern arises if a nevus changes rapidly in size, color, shape, or becomes symptomatic (itchy, bleeding) Using criteria such as asymmetry, border irregularity, color variation, diameter, evolution helps in assessing risk Can You Prevent It? Sun protection helps reduce formation of new nevi and limits pigment changes in existing ones Monitoring skin for new or changing lesions is important Avoiding excessive UV exposure and protecting skin after sun damage may help 👉 How Piel AI Can Help Piel AI allows you to document and track nevi over time using photos. While not diagnostic, it helps you notice changes in appearance or number and decide when professional evaluation might be needed. Summary Melanocytic nevi (papilloma-nevus) are benign pigmented or slightly raised skin lesions. They vary in texture, color, and shape, and are influenced by genetics and sun exposure. Most are harmless, but changes warrant attention. Monitoring and skin protection are key to early detection.

Explore more conditions

Learn about other skin and hair conditions.

View all conditions →