Two Cases of Vitiligo Developed on the Persisting Dermal Melanocytosis: Is There a Difference between Epidermal Melanocytes and Dermal Melanocytes?

[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.

Blue vitiligo following intralesional injection of psoralen combined with ultraviolet B radiation therapy

A 23-year-old Chinese man presented with a 16-month history of white patches on his abdomen and neck. He had previously received an intralesional injection of psoralen along with narrowband psoralen ultraviolet B radiation (PUVB) therapy. Blue macules had appeared in and around the injection sites 1 week later. Dermoscopy revealed blue spots and reticular telangiectasia within the white patches. Histological examination revealed an absence of epidermal melanocytes and pigment in the basal layer, as well as deposition of melanophages between collagen bundles or surrounding blood vessels and appendages in the middle and lower parts of the dermis. A diagnosis of blue vitiligo was made. The blue colour faded gradually over time. Our case provides direct evidence to support the previous surmise that PUVB can contribute to blue vitiligo. To our knowledge, this is only the fourth reported case of blue vitiligo in the English literature.