In Vivo Characterization of Mucin and Amyloid Deposits in Primary Basal Cell Carcinoma through Reflectance Confocal Microscopy: A Correlation with Histopathology.

Basal cell carcinoma (BCC) is the most common keratinocyte carcinoma and the most prevalent skin cancer in humans, worldwide. BCC is histologically characterized by the proliferation of basaloid cells, arranged in globular masses of varying size, often separated from the surrounding stroma by optically empty spaces. Although attributed to tumor retraction during tissue processing for the preparation of pathology slides, these spaces are also seen on cryostat sections. The aim of this study is to in vivo characterize amyloid and mucin deposits in primary BCC lesions through RCM, followed by histopathological correlation. We included twenty-two consecutive subjects totaling thirty-one primary BCCs. Each lesion underwent the same evaluation protocol which included: clinical and dermoscopic images, RCM imaging, excisional biopsy under local anesthesia, and histopathological examination (colloidal iron and cytokeratin 34betaE12 stains). Hypo-reflective peritumoral clefts and hyper-reflective globules were measured on RCM images and compared to mucin and amyloid deposits seen on histology slides. The mean differences between RCM and histology measurements in both mucin and amyloid were not statistically significant. There were medium and strong correlations between RCM and histology regarding mucin and amyloid deposits, respectively.