Nevus

A nevus (plural: nevi) refers to a broad classification of various skin growths that are typically characterized by distinct pigmentation. Commonly known as a mole, a nevus can be present at birth (congenital) or appear later in life (acquired).

Nevus

Introduction

The term "nevus" is derived from the Latin word for "birthmark". Nevi are generally benign but in rare cases, can transform into malignant melanoma, a type of skin cancer. They can be found anywhere on the body and may vary in size, shape, and color.

Types of Nevi

• There are several types of nevi, including:
• Melanocytic Nevus: The most common type of nevus, often appearing as small brown spots or bumps. This type includes congenital melanocytic nevi, junctional nevi, and compound nevi.
• Dysplastic Nevus (Atypical Mole): These are larger than typical moles and have irregular shapes and coloration. They may carry a higher risk of developing into melanoma.
• Blue Nevus: Characterized by a blue or blue-black color, these are caused by pigment deep within the dermis.
• Spitz Nevus: Often seen in children, these are typically dome-shaped and may be confused with melanoma.

Causes and Risk Factors

Nevi are primarily caused by the proliferation of melanocytes, the skin's pigment-producing cells. Factors that may contribute to the development of nevi include genetics, sun exposure, and hormonal changes, such as those experienced during pregnancy.

Clinical Presentation

A typical nevus presents as a uniformly colored brown spot or small bump. Nevi can vary significantly in color, ranging from skin-colored to black. They may be flat or raised, smooth or rough, and some may have hair growing from them.

Diagnosis

Nevi are usually diagnosed through a visual skin examination. Dermoscopy, a technique that uses a special magnifying lens to examine the skin, can help differentiate a benign nevus from a malignant lesion. In uncertain cases, a skin biopsy may be performed for histopathological analysis.

Treatment and Management

Most nevi require no treatment. However, if a nevus changes in size, shape, or color, or becomes symptomatic, it may be removed and examined to rule out melanoma. Nevus removal can be done through surgical excision, laser treatment, or cryotherapy.

Prognosis

The vast majority of nevi are benign and carry an excellent prognosis. However, the transformation of a nevus into melanoma, while rare, is a serious complication. Regular self-examination of the skin for new or changing nevi is crucial for early detection of potential skin cancers.

See Also

• Melanoma
• Dermatology
• Skin Cancer
• Melanocyte
• Dysplastic Nevus

References

Nevus Resources
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