Confocal microscopy – Working principle and applications in dermatology

Abstract

Confocal microscopy (CFM) is a novel, non-invasive tool with diagnostic and prognostic value. It has utility in a wide array of dermatological conditions, tele-dermatopathology, and dermatological research. The image contrast is imparted by the differential refractive properties of subcellular structures. Certain stains are also used to accentuate the image contrast. CFM enables the visualization of tissues both in vivo and ex vivo (after excision). Both reflectance (in vivo and ex vivo) and fluorescence modes (ex vivo) of CFM are utilized for imaging. One can view 3D images with a near histological resolution, but with a limited depth of penetration. CFM has reduced the number of biopsies required in the evaluation of skin cancers. However, conventional histopathology remains the gold standard in tumor diagnosis. The in vivo reflectance mode CFM has found applications in dermato-oncology, inflammatory dermatoses, cutaneous infections and infestations, skin aging, and pigmentary disorders. The ex vivo CFM facilitates the immediate perioperative examination of excised tissues. The limited depth of view, photobleaching (in fluorescence mode CFM), high cost, and steep learning curve are the disadvantages. The future of CFM appears promising with the introduction of modified microscopes, the use of specific stains, and the incorporation of artificial intelligence.