In Vivo Multiphoton Microscopy of Basal Cell Carcinoma

Abstract

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.

Figure 1. The Imaging Procedure of a Skin Lesion on the Face

Using the multiphoton microscopy (MPM)-based clinical tomograph (MPTflex).

Figure 2. Basal Cell Carcinoma (BCC) (Superficial and Nodular Components)

A, Clinical image (DermLite FOTO, DermLite Inc). B, Multiphoton microscopy (MPM) en-face images (x-y scans) of the stratum corneum at z = 0 μm, of keratinocytes in the stratum spinosum at z = 15 μm, of a nest of basaloid cells (green) surrounded by collagen (blue) and elastin fibers (green) imaged at different depths: z = 30 μm, 45 μm, and 60 μm. C, Cross-sectional view (x-z scan) corresponding to a vertical plane through the same interrogating volume shown on the left. DEJ indicates dermo-epidermal junction. D, Hematoxylin-eosin– stained histologic section of the lesion; original magnification ×40. Both the MPM and the histologic images show a mucinous stroma adjacent to the tumor mass (case 2). B-D, Arrowheads indicate mucinous stroma.

Figure 3. Superficial Basal Cell Carcinoma (BCC)

A, Clinical image (DermLite FOTO, DermLite Inc). Scale bar is 2 mm. B, Multiphoton microscopy (MPM) image of the stratum spinosum (dashed circle) (z = 40 μm) showing tumor elongated cells aligned in 1 direction (arrow) in the epidermis. C, MPM image of the lower epidermis (z = 50 μm) showing the tip of a tumor BCC nest (arrowheads) attached to the undersurface of the epidermis. D, MPM image of the same nest (arrowheads) showing palisading in the peripheral cell layer. This image represents a z-projection of 3 consecutive images (3-μm step) for an increase in the depth of field and better visualization. E, MPM image of the same nest in a deeper layer (arrowheads) (z = 130 μm). F, Hematoxylin-eosin–stained histologic section of the lesion; original magnification ×40. B-F, Scale bar is 40 μm (case 1).

Figure 4. Nodular and Superficial Basal Cell Carcinoma (BCC)

A, Clinical image (DermLite FOTO, DermLite Inc). Scale bar is 2 mm. B, Multiphoton microscopy (MPM) image of the stratum granulosum (z = 20 μm) showing elongated tumor cells aligned in 1 direction (arrow). C, MPM image of the lower epidermis (z = 50 μm) showing tumor cells aligned in 1 direction (arrow). D, MPM image showing parallel collagen fibers (blue) on top of tumor. E, MPM image showing parallel collagen fibers surrounding a BCC tumor nest. Arrowheads indicate palisading in the peripheral cell layer. F, Histologic section of the lesion (hematoxylin-eosin, original magnification ×40). B-F, Scale bar is 40 μm (case 9).