Melanocytic nevus

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Melanocytic nevus
Synonyms	Mole, nevocytic nevus
Pronounce	N/A
Specialty	N/A
Symptoms	Pigmented skin lesion, usually brown, black, or skin-colored
Complications	Malignant melanoma
Onset	Childhood or early adulthood
Duration	Lifelong
Types	N/A
Causes	Genetic factors, UV radiation
Risks	Sun exposure, family history of melanoma
Diagnosis	Dermatoscopy, biopsy
Differential diagnosis	Seborrheic keratosis, lentigo, melanoma
Prevention	Sun protection, regular skin checks
Treatment	Surgical excision, laser therapy
Medication	N/A
Prognosis	N/A
Frequency	Common
Deaths	N/A

A modern polarized dermatoscope.

A dermatoscope.

Abraham Lincoln famously had a mole on his right cheek

Micrograph of an intradermal melanocytic nevus

A melanocytic nevus is a type of skin lesion that is commonly referred to as a mole. These lesions are typically benign and are composed of nevus cells, which are a type of melanocyte. Melanocytic nevi can appear anywhere on the body and vary in color, size, and shape.

Classification

Melanocytic nevi are classified based on their location within the layers of the skin and their appearance. The main types include:

• Junctional nevi: These are located at the junction of the epidermis and dermis. They are usually flat and uniformly pigmented.
• Compound nevi: These have both junctional and dermal components, often appearing as slightly raised lesions.
• Intradermal nevi: These are located entirely within the dermis and are typically raised and flesh-colored.

Appearance

Melanocytic nevi can vary widely in appearance. They may be:

• Flat or raised
• Round or oval
• Uniformly colored or variegated

The color of a melanocytic nevus can range from pink to dark brown, depending on the amount of melanin present.

Development

Melanocytic nevi often develop during childhood and adolescence, with the number of nevi typically peaking in the third decade of life. They may change in appearance over time, sometimes becoming more raised or changing in color.

Pathophysiology

The development of melanocytic nevi is influenced by genetic factors and sun exposure. Nevus cells are derived from neural crest cells and are similar to melanocytes, the cells responsible for producing melanin.

Potential for Malignancy

While most melanocytic nevi are benign, some may develop into melanoma, a type of skin cancer. Features that may suggest malignancy include:

• Asymmetry
• Border irregularity
• Color variation
• Diameter greater than 6 mm
• Evolving shape or color

Management

Most melanocytic nevi do not require treatment unless they are symptomatic or show signs of malignancy. In such cases, a biopsy or excision may be performed to rule out melanoma.

See also

• Melanoma
• Skin cancer
• Dermatology
• Nevus