Follicular Becker Nevus: an Unusual Clinical and Dermoscopic Manifestation.

Introduction

Becker nevus (BN) is characterized by a unilateral, hairy, pigmented macule usually involving the chest or scapular region. We hereby reported a specific case of follicular BN presenting follicular macules and maculopapules, and described its dermoscopic manifestation.

Case Presentation

A 20-year-old female presented with a 12-year history of multiple clustered asymptomatic brown macules and maculopapules affecting the inside of the left upper arm (Figure 1A). The pigmented lesions gradually increased in the initial phase and then stabilized. No other accompanied systemic abnormality was found. Familiar and medical histories were unremarkable. The dermoscopy revealed multiple brown round perifollicular macules with thicker hairs in the follicles (Figure 1B). The histopathological examination showed hyperkeratosis, acanthosis, and darkly pigmented basal cell layer (Figure 1C). A diagnosis of follicular BN was made.

Figure 1

(A) Multiple clustered brown follicular macules and maculopapules affecting the inside of the left upper arm. (B) The dermoscopy revealed multiple brown round perifollicular macules with thicker hairs in the follicles. (C) The histopathology showed hyperkeratosis, acanthosis, and darkly pigmented basal cell layer (H&E staining; ×200 magnification).

Discussion

BN, also called pigmented hairy epidermal nevus, is characterized by a unilateral, hairy, pigmented macule usually involving the upper chest or the scapular region, a few cases present multiple or bilateral. The pathogenesis is still unclear. The plausible explanations for BN include mosaicism and an androgen-dependent lesion [1]. BN has male predilection, with a 2:1 to 5:1 predominance of men over women [1]. BN commonly appears during adolescence and some cases are congenital. The lesions usually present as an asymptomatic well-demarcated, irregular, brown macule with a geographic or block-like configuration. However, Manchanda et al first reported an unusual clinical manifestation of BN in 2020, which presented follicular lesions [2]. They speculated that some BN might begin from perifollicular lesions and follicular epithelium might hold a significant role in the etiopathogenesis. The mechanism of follicular BN and the pathogenesis of BN remain to be further studied.

BN usually do not require treatment, and some potential therapeutic options were taken due to cosmetic requirement, including electrolysis, waxing, makeup, laser treatment, and topical therapy. Currently, no consensus has yet been reached in the literature regarding which treatment is preferred and success with each treatment varies widely.

Conclusions

Follicular BN is an unusual clinical variant. The dermatologist should be aware of the unusual clinical manifestation of BN, which could permit to quickly solve the clinical doubts and reassure the patient.