Nevus of Ota

Nevus of Ota
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Nevus of Ota is a dermal melanocytic hamartoma, which presents as a blue or grayish patch on the face, particularly around the eye area. It is a type of dermal melanocytosis and is more commonly observed in individuals of Asian descent, particularly Japanese and Chinese populations. The condition is named after the Japanese dermatologist Masao Ota, who first described it in 1939.

Presentation

Nevus of Ota typically appears as a unilateral, bluish or grayish discoloration on the face. The pigmentation is due to the presence of melanocytes in the dermis. It most commonly affects the areas innervated by the first and second branches of the trigeminal nerve, including the forehead, temple, periorbital region, and cheek. In some cases, the sclera and other parts of the eye may also be involved, leading to ocular complications.

Pathophysiology

The exact cause of Nevus of Ota is not well understood, but it is believed to result from the failure of neural crest cells to migrate properly during embryonic development. These cells remain in the dermis and produce melanin, leading to the characteristic pigmentation. The condition is usually congenital, but it can also appear during adolescence.

Diagnosis

Diagnosis of Nevus of Ota is primarily clinical, based on the characteristic appearance of the lesion. Dermatoscopy can be used to examine the lesion more closely. In some cases, a biopsy may be performed to rule out other conditions, such as melanoma.

Treatment

While Nevus of Ota is a benign condition, treatment may be sought for cosmetic reasons. The most effective treatment is laser therapy, particularly with Q-switched lasers, which target the melanin in the dermis and help to lighten the pigmentation. Multiple sessions are often required for optimal results.

Prognosis

Nevus of Ota is a benign condition and does not typically pose any health risks. However, there is a small risk of malignant transformation into melanoma, particularly in the ocular region. Regular monitoring by a dermatologist or ophthalmologist is recommended.

Also see

• Nevus of Ito
• Mongolian spot
• Melanoma
• Dermal melanocytosis

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