[What's new in clinical dermatology?]

In this article, we performed a review of all new data of clinical relevance for the dermatologists that were published in the medical literature between September, 2017 and September, 2018. Besides advances that will be useful in day-to-day dermatological practice, we intended to give a more general perspective to this review by taking into account certain international health issues that might in final concern each of us in a globalized world. Focus were more particularly done on the following topics: infectious diseases (including sexually transmitted infections), neglected tropical diseases, adverse effects of drugs, bullous diseases, allergology, wound healing, dermatology on black skin, and public health dermatology.

Skin cancers in patients of skin phototype V or VI with xeroderma pigmentosum type C (XP-C): A retrospective study

BACKGROUND

Xeroderma pigmentosum (XP) is a rare genetic disease comprising 7 subgroups, A to G, all of which are associated with early onset of several forms of skin cancer. Our main objective was to determine the prevalence of skin cancers in a cohort of dark-skinned XP-C patients in Mayotte.

PATIENTS AND METHODS

A single-centre cohort consisting of all XP patients was followed in the island of Mayotte from December 2015 to May 2017 by dermatologists from the University Hospital of Saint-Denis (Reunion) during the course of dermatological missions.

RESULTS

Eighteen patients of median age 12.9 years (7 female/11 male) belonging to 14 families were included. All had XP-C and carried the same mutation. Median age at clinical diagnosis of XP was 1.8 years. A total of 144 skin cancers (94 squamous cell carcinomas [SCC], 30 basal cell carcinomas [BCC], 14 melanomas, 5 sarcomas and 1 sarcomatoid carcinoma) were observed in 11 of the 18 patients (61%). Eleven patients (61%) had at least 1 SCC, 6 (33%) had at least 1 BCC, 6 (33%) had at least 1 melanoma, and 4 (22%) had at least 1 sarcoma. In all, 95.5% of the cancers occurred in light-exposed skin areas. Median age was 5.4 years for the initial cancer and 6.4 years for the second. SCCs and sarcomas occurred earlier than CBCs and melanomas (P<0.0001). All patients had mild to severe poikiloderma and presented photophobia, and 50% had pigmented palmoplantar lesions. One-third had oral mucosal involvement while 78% had ocular or palpebral lesions. Nail and hair involvement was recorded in 17% of patients. The median sun protection score (evaluated on a 7-item scale) was 6/7. The median score on the quality-of-life questionnaire (DLQI) was 4/30. Severity of poikiloderma was significantly correlated with the occurrence of skin cancers.

DISCUSSION AND CONCLUSION

Our cohort showed a high prevalence of skin cancer in XP-C patients of phototype V and VI exposed to UV radiation in a tropical region. SCCs were the most common tumours. The prevalence of melanoma was high, with major risk compared to controls of the same skin phototype. In addition, we found a high prevalence of sarcomas (5 patients). Initial cancers occurred early (5.4 years) compared to data from the literature, and SCCs and sarcomas occurred significantly sooner than melanomas and BCCs.

[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.