Giant congenital nevi

Giant Congenital Nevi
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Synonyms	Giant congenital melanocytic nevus
Pronounce	N/A
Specialty	N/A
Symptoms	Large pigmented skin lesions present at birth
Complications	Melanoma, psychosocial impact
Onset	Congenital
Duration	Lifelong
Types	N/A
Causes	Genetic mutations
Risks
Diagnosis	Clinical examination, biopsy
Differential diagnosis	N/A
Prevention	N/A
Treatment	Surgical excision, laser therapy, monitoring
Medication	N/A
Prognosis	Variable, risk of malignancy
Frequency	Rare
Deaths	N/A

Giant congenital nevi (GCN), also known as giant congenital melanocytic nevi, are large pigmented skin lesions that are present at birth. These nevi are characterized by their size, typically defined as being greater than 20 cm in diameter when fully grown. They are a type of congenital melanocytic nevus, which are benign proliferations of melanocytes, the cells responsible for producing melanin, the pigment that gives skin its color.

Etiology

Giant congenital nevi are thought to arise from genetic mutations that occur during fetal development. These mutations lead to the proliferation of melanocytes in a localized area of the skin. The exact genetic mechanisms are not fully understood, but they are believed to involve mutations in genes that regulate cell growth and differentiation.

Clinical Presentation

Giant congenital nevi are usually present at birth or become apparent shortly thereafter. They can vary in color from light brown to black and may have a smooth, rough, or nodular surface. The nevi can occur anywhere on the body but are most commonly found on the trunk and extremities. In some cases, they may cover large areas of the body, leading to significant cosmetic and psychological concerns.

Complications

One of the most serious complications associated with giant congenital nevi is the increased risk of developing melanoma, a type of skin cancer. The risk of melanoma in individuals with giant congenital nevi is estimated to be between 5% and 10% over a lifetime. Other potential complications include neurocutaneous melanosis, a condition where melanocytes proliferate in the central nervous system, leading to neurological symptoms.

Diagnosis

The diagnosis of giant congenital nevi is primarily clinical, based on the appearance and size of the lesion. A biopsy may be performed to rule out malignancy or to confirm the diagnosis. Imaging studies, such as MRI, may be used to assess for neurocutaneous melanosis if neurological symptoms are present.

Management

Management of giant congenital nevi involves regular monitoring for changes that may indicate malignancy. Surgical excision is often considered, especially if the nevus is located in an area that is easily accessible and if there is a high risk of melanoma. Other treatment options include laser therapy to reduce pigmentation and improve cosmetic appearance. Psychological support may also be beneficial for individuals dealing with the social and emotional impact of having a large visible nevus.

Prognosis

The prognosis for individuals with giant congenital nevi varies depending on the size and location of the nevus and the presence of any complications. Regular follow-up with a dermatologist is essential to monitor for changes that may indicate malignancy.

Also see

• Congenital melanocytic nevus
• Melanoma
• Neurocutaneous melanosis
• Dermatology

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