[Vitiligo occurring on dermal melanocytosis (nevus of Ota) in a dark-skinned patient].

BACKGROUND: Nevus of Ota is a rare disease most frequently found in Asians. It presents clinically as a bluish gray hyperpigmentation of one side of the face. Transformation into melanoma and glaucoma are the main risks. The appearance of vitiligo lesions with poliosis within a nevus of Ota is exceptional.

PATIENTS AND METHODS: A 22-year-old female patient with a nevus of Ota consulted for depigmentation of the eyelashes. Physical examination revealed hyperpigmentation in the right orbitofrontal part of her face, achromic macules and eyelash poliosis. A diagnosis was made of vitiligo developing on a nevus of Ota. Ophthalmologic examination showed hyperpigmentation of the sclera. Regular dermatologic and ophthalmologic follow-up was instituted.

DISCUSSION: Vitiligo is a condition characterized by the development of depigmented lesions secondary to chronic degradation of the melanocytes of the epidermis and the follicles. Its occurrence on congenital nevus and melanoma has already been reported. However, its appearance in dermal melanocytosis is very rare. Since the first observation of this association in 1979, only 4 other cases have been reported. The pathogenic mechanisms of this association are still poorly understood. Histopathological examination generally shows a loss of epidermal melanocytes, especially in the basal layer, while dermal melanocytes remain unaffected. In this context, vitiligo developed on dermal melanosis appears to result from the difference between the properties of normal (epidermal) melanocytes and ectopic (dermal) melanocytes.

CONCLUSION: Association of vitiligo with nevus of Ota is rare. Herein, we report a new case in a dark-skinned subject.