Noninvasive Screening of Basal Cell Carcinomas: A Comparison of the Structure and Physical Properties of Large and Small Nodular Lesions Using Vibrational OCT and Histopathology

Approximately 5.4 million nonmelanoma skin cancers are treated each year in the US. Of this number 80 to 90% are basal cell carcinomas. In this study, we compare optical coherence tomography (OCT) images and vibrational optical coherence tomography (VOCT) measurements made on small and large nodular basal cell carcinomas (BCCs) using histopathology, OCT images, and VOCT physical measurements. OCT images were broken into green, blue, and red subchannel images and compared to histopathology conducted on the excised tissue. While our results suggest that both small and large BCCs have similar morphologies that include circular nodules with palisading cells surrounding the lesions, no part of the excised lesions appeared like normal skin. In the small lesion, the nodule is surrounded by tissue that may be considered to have “clear” margins even though the rete ridges are missing, and the ECM does not resemble normal skin. The edges of the lesion are free of palisading cells with only some inflammatory cells being present. In contrast, the mechanovibrational spectrum of the large lesion appeared to have an increased amount of large fibrotic peaks with decreased vibrations for normal cells and cancer-associated fibroblasts compared to the smaller nodule. These results indicate that it is possible to identify the location of the BCC nodules noninvasively using VOCT. The ability to noninvasively identify nodular BCCs using this technique makes it a useful adjunct to visual inspection and dermoscopy to identify cancerous lesions seen in the clinic. Since VOCT can be operated remotely, it can serve as a noninvasive screening tool to be used by general practitioners in areas where dermatologists are in short supply.