Follicular Melanocytes in Frontal Fibrosing Alopecia: An Immunohistochemical Study With Trichoscopic Correlation

Abstract

Background:Frontal fibrosing alopecia (FFA) is a scarring alopecia that affects the frontotemporal hairline. Clinically, it may develop with cutaneous hypopigmentation of the affected areas, which has been associated with a reduction in the epidermal melanocyte count. In trichoscopy, peripilar white halos can be observed, which have been associated with fibrosis in other scarring alopecias.Objective:To evaluate the trichoscopic, histopathological and immunohistochemical characteristics of the peripilar white halos in FFA patients.Materials and methods:We conducted a descriptive cross-sectional study that included 12 patients with FFA presenting peripilar white halos. Two 2-mm punch trichoscopy-guided biopsies were performed in all patients, one fragment for vertical section and another for horizontal section. The vertical sections were stained with Fontana-Mason and Melan-A.Results:On trichoscopic examination, peripilar white halos ≤ 1 mm in size were observed on the affected scalp. In vertical sections, a reduction in basal melanin pigmentation and a decrease in the melanocyte count in the upper segment of the hair follicle were observed with Fontana-Masson staining and Melan-A immunostaining, respectively.Limitations:The small sample size and absence of a control group.Conclusion:This study shows follicular melanocyte involvement in FFA, and this finding may be associated with the peripilar white halos observed in trichoscopy.

Choose your biopsy site wisely — the utility of dermoscopy in the diagnosis of Bowen’s disease of the face

“…Dermoscopy has already been reported as a useful tool for the selection of a biopsy site and therefore facilitation of the diagnosis of melanocytic lesions [7,8], cicatricial alopecia [9][10][11][12][13], extramammary Paget's disease [14], melanonychia [15] and penile sclerosing granuloma [16]. Dermoscopy may not only aid selection of the biopsy site but also guide nail abrasion for mycological samples in case of onychomycosis [17].…”

Frontal fibrosing alopecia sparing a dermal melanocytic nevus: a report of two cases of Renbök phenomenon

“…It is also unclear how nevus-associated melanocytes could be protected in this process. 8,9 Previously, Pirmez et al 10 reported the pseudo 'fringe sign' in FFA, defined as sparing of the hairline in the course of the disease. The presented cases do not however represent pseudo 'fringe sign', as hairs were preserved only within and around DNs.…”