In Vivo Multiphoton Microscopy of Basal Cell Carcinoma.

IMPORTANCE Basal cell carcinomas (BCCs) are diagnosed by clinical evaluation, which can include dermoscopic evaluation, biopsy, and histopathologic examination. Recent translation of multiphoton microscopy (MPM) to clinical practice raises the possibility of noninvasive, label-free in vivo imaging of BCCs that could reduce the time from consultation to treatment. OBJECTIVES To demonstrate the capability of MPM to image in vivo BCC lesions in human skin, and to evaluate if histopathologic criteria can be identified in MPM images. DESIGN, SETTING, AND PARTICIPANTS Imaging in patients with BCC was performed at the University of California-Irvine Health Beckman Laser Institute & Medical Clinic, Irvine, between September 2012 and April 2014, with a clinical MPM-based tomograph. Ten BCC lesions were imaged in vivo in 9 patients prior to biopsy. The MPM images were compared with histopathologic findings. MAIN OUTCOMES AND MEASURES MPM imaging identified in vivo and noninvasively the main histopathologic feature of BCC lesions: nests of basaloid cells showing palisading in the peripheral cell layer at the dermoepidermal junction and/or in the dermis. RESULTS The main MPM feature associated with the BCC lesions involved nests of basaloid cells present in the papillary and reticular dermis. This feature correlated well with histopathologic examination. Other MPM features included elongated tumor cells in the epidermis aligned in 1 direction and parallel collagen and elastin bundles surrounding the tumors. CONCLUSIONS AND RELEVANCE This study demonstrates, in a limited patient population, that noninvasive in vivo MPM imaging can provide label-free contrast that reveals several characteristic features of BCC lesions. Future studies are needed to validate the technique and correlate MPM performance with histopathologic examination.