Nevus unius lateris

Nevus unius lateris

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Nevus unius lateris on the right side of the body

Nevus unius lateris is a type of epidermal nevus that is characterized by a unilateral distribution of skin lesions. These lesions are typically present at birth or develop in early childhood and are confined to one side of the body, following the lines of Blaschko.

Clinical Presentation

Nevus unius lateris presents as a linear or whorled pattern of hyperpigmented or verrucous plaques. These lesions are often asymptomatic, but they can sometimes be associated with itching or irritation. The distribution of the nevus is typically limited to one side of the body, which is a hallmark of this condition.

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Close-up of nevus unius lateris showing verrucous texture

Pathophysiology

The condition is thought to arise from a post-zygotic somatic mutation in the embryo, leading to a mosaic pattern of affected and unaffected skin. The lesions follow the lines of Blaschko, which are believed to represent pathways of embryonic cell migration.

Diagnosis

Diagnosis of nevus unius lateris is primarily clinical, based on the characteristic appearance and distribution of the lesions. A skin biopsy may be performed to confirm the diagnosis and rule out other conditions. Histologically, the lesions show hyperkeratosis, acanthosis, and papillomatosis.

Treatment

Treatment is not always necessary unless the lesions cause symptoms or cosmetic concerns. Options include topical keratolytics, cryotherapy, laser therapy, and surgical excision. The choice of treatment depends on the size, location, and severity of the lesions.

Prognosis

The prognosis for individuals with nevus unius lateris is generally good. The lesions are benign and do not typically undergo malignant transformation. However, they may persist throughout life and can sometimes become more pronounced with age.

Related pages

• Epidermal nevus
• Lines of Blaschko
• Somatic mutation