Should reflectance confocal microscopy be the gold standard for basal cell carcinoma diagnosis?

Abstract

Reflectance confocal microscopy (RCM) is a novel application of scanning confocal microscopy that generates high spatiotemporal resolution images of the superficial layers of the skin in real time, performed by directly applying a confocal scanning head to the skin. Illumination is provided by infrared laser sources that generate low energy, high penetrance photons. Different structures provide high contrast in the skin, most notably melanin-containing cells and structures, for example, melanocytes and melanosomes, among others [1]. Although penetration should still be improved (current setups enable depths of less than 0.3 mm) RCM is a powerful diagnostic tool owing to its high reproducibility and high resolution, which is comparable to that of conventional histology [2]. Arguably, its most important feature is that it is a bona fide noninvasive technique that permits iterative analytical sampling over time without affecting the area under evaluation. In recent years, RCM has experienced a manifold increase in the number of studies and publications [2,3]. These efforts have yielded a relatively clear and complete picture of the skin under physio logical conditions. They have also described the most important RCM features of a number of skin diseases, most notably epidermoid (squamous) carcinoma, basal cell carcinoma (BCC) and melanoma [3]. In this article, I will focus on the most recent findings regarding the imaging and diagnosis of BCC using RCM, provide a brief state-of-the-art regarding BCC microscopic-level diagnosis using RCM and provide insight into current research to improve the use of RCM for diagnosis and evaluation of its therapeutic response.