Abstract

Background  Extra-facial melasma is a prevalent dermatosis in some populations with special characteristics in relation to its clinical aspects and probable etiopathogenic factors. Few studies have attempted to address this alteration of pigmentation, which has become a challenge in clinical Dermatology. Objective  To assess the clinical histopathological and immunohistochemical characteristics of extra-facial melasma, comparing affected, and unaffected sites. Methods  Case-control study with 45 patients in each group (melasma and disease-free volunteers), assessing their clinical characteristics. In 36 patients, biopsies were performed on the lesion and the normal perilesional skin. Specimens were stained with HE and Fontana-Masson, and melanocytes analysed by immunohistochemistry. Objective measurements were accomplished by a specifically designed image analysis software. Results  The melasma group had a mean age ± SD of 56.67 ± 8 years, the majority of them were women (86.7%) and 82.1% of the female cases had reached menopause. There were no significant differences between groups in terms of presence of comorbidities, use of medications or hormone therapies. For extra-facial melasma patients, family history of this dermatose and of previous facial melasma was significantly higher than in the control group (P < 0.05). The HE staining showed increased rectification and basal hyperpigmentation, solar elastosis, and collagen degeneration in the pigmented area (P < 0.05). There was a significant increase in melanin density in melasma biopsies, but the immunohistochemical tests did not detect a difference between the groups in terms of number of melanocytes. Conclusion  Extra-facial melasma appears to be related to menopause, family history, and personal history of facial melasma, in the studied population. Histopathology revealed a pattern similar to what has been described for facial melasma, with signs of solar degeneration, and a similar number of melanocytes, when comparing patients, and controls, suggesting that the hyperpigmentation is most likely the result of abnormal melanin production or distribution.

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Publisher Full Text

Authors

Ritter CG, Fiss DV, Borges da Costa JA, de Carvalho RR, Bauermann G, Cestari TF

Institution

Department of Dermatology, Hospital de Clínicas de Porto Alegre, School of Medicine, Federal University of Rio Grande do Sul, Brazil Experimental Pathology Laboratory, Hospital de Clínicas de Porto Alegre, Brazil Department of Physics of Federal University of Santa Maria, Santa Maria, Brazil ANIMATI - Computação Aplicada, Santa Maria, Brazil.

Source

Journal of the European Academy of Dermatology and Venereology : JEADV : 2012 Jul 24 pg

Pub Type(s)

JOURNAL ARTICLE

Language

ENG

PubMed ID

22827850