Clinical and Dermoscopic Patterns of Basal Cell Carcinoma and Its Mimickers in Skin of Color: A Practical Summary

Abstract

The diagnosis of basal cell carcinoma (BCC) in dark phototypes can be a challenging task due to the lack of relevant clues and its variable presentation. In this regard, there is growing evidence that dermoscopy may benefit the recognition of BCC even for skin of color (SoC). The objective of this review is to provide an up-to-date overview on clinical and dermoscopic patterns of BCC in SoC, also comparing such findings with those of the main clinical mimickers reported in the literature. A comprehensive search of the literature through the PubMed electronic database was carried out in order to identify papers describing the clinical and dermoscopic features of BCC in dark phototypes (IV-VI). By finding macroscopic clinical presentations of BCCs in SoC patients and any possible clinical mimickers considered in the retrieved papers, we built a differential diagnosis list and analyzed the dermoscopic findings of such conditions to facilitate the diagnosis of BCC. BCC in darker skin may present as pigmented nodular lesions, pigmented patches or plaques, ulcers, erythematous nodular lesions, erythematous plaques or patches, or scar-like lesions, depending on its subtype and body site. The differential diagnosis for BCC in patients with SoC includes squamous cell carcinoma, melanoma, nevi, adnexal tumors and sebaceous keratosis. Additionally, it differs from that of Caucasians, as it also includes lesions less common in fair skin, such as dermatosis papulosa nigra, melanotrichoblastoma, and pigmented dermatofibrosarcoma protuberans, and excludes conditions like actinic keratosis and keratoacanthoma, which rarely appear in darker skin. The resulting differences also include infectious diseases such as deep cutaneous mycosis and inflammatory dermatoses. The most prevalent differentiating dermoscopic feature for BCC includes blue, black and gray dots, though arborizing vessels still remain the predominant BCC feature, even in dark phototypes. Diagnostic approach to BCC in dark-skinned patients varies due to the prevalence of dermoscopy findings associated with hyperpigmented structures. Clinicians should be aware of such points of differentiation for a proper management of this tumor in SoC.

Keywords: basal cell carcinoma; cutaneous dermatoses; cutaneous neoplasms; dermoscopy; skin cancer; skin infections; skin of color.

Figure 1

Presenting macroscopic and dermoscopic presentation of BCC in Indian patient. Image (A) showing a pigmented patch and image (B) indicating the respective dermoscopy image with the presence of structureless black or leaf-like areas in a pink stroma.

Figure 2

Presenting a sebaceous keratosis on the skin of the ring finger of a dark-skinned individual as a pigmented patch (similar presentation as BCC or acral melanoma) (Image (A)). Image (B) shows the differently tanned finger-like structures, which is dermoscopy characteristic of sebaceous keratosis.

Figure 3

Presenting dermoscopy images of a nodular lesion-BCC in an Indian patient. Image (A) shows the pigmented structures on the periphery of the lesions with blue-white veil a centrally while in image (B) the arborising vessels are present on a pink-brownish stroma with co-existing white chrysalis structures.