Evaluation of a Combined Reflectance Confocal Microscopy-Optical Coherence Tomography Device for Detection and Depth Assessment of Basal Cell Carcinoma

Abstract

Importance: The limited tissue sampling of a biopsy can lead to an incomplete assessment of basal cell carcinoma (BCC) subtypes and depth. Reflectance confocal microscopy (RCM) combined with optical coherence tomography (OCT) imaging may enable real-time, noninvasive, comprehensive three-dimensional sampling in vivo, which may improve the diagnostic accuracy and margin assessment of BCCs.

Objective: To determine the accuracy of a combined RCM-OCT device for BCC detection and deep margin assessment.

Design, setting, and participants: This pilot study was carried out on 85 lesions from 55 patients referred for physician consultation or Mohs surgery at Memorial Sloan Kettering Skin Cancer Center in Hauppauge, New York. These patients were prospectively and consecutively enrolled in the study between January 1, 2017, and December 31, 2017. Patients underwent imaging, with the combined RCM-OCT probe, for previously biopsied, histopathologically confirmed BCCs and lesions clinically or dermoscopically suggestive of BCC. Only patients with available histopathologic examination after imaging were included.

Main outcomes and measures: Improvements in sensitivity, specificity, and diagnostic accuracy for BCC using the combined RCM-OCT probe as well as the correlation between OCT-estimated depth and histopathologically measured depth were investigated.

Results: In total, 85 lesions from 55 patients (27 [49%] were female and 28 [51%] were male with a median [range] age of 59 [21-90] years) were imaged. Imaging was performed on 25 previously biopsied and histopathologically confirmed BCCs and 60 previously nonbiopsied but clinically or dermoscopically suspicious lesions. Normal skin and BCC features were correlated and validated with histopathologic examination. In previously biopsied lesions, residual tumors were detected in 12 of 25 (48%) lesions with 100% sensitivity (95% CI, 73.5%-100%) and 23.1% specificity (95% CI, 5.0%-53.8%) for combined RCM-OCT probe. In previously nonbiopsied and suspicious lesions, BCCs were diagnosed in 48 of 60 (80%) lesions with 100% sensitivity (95% CI, 92.6%-100%) and 75% specificity (95% CI, 42.8%-94.5%). Correlation was observed between depth estimated with OCT and depth measured with histopathologic examination: the coefficient of determination (R2) was 0.75 (R = 0.86; P < .001) for all lesions, 0.73 (R = 0.85; P < .001) for lesions less than 500 μm deep, and 0.65 (R = 0.43; P < .001) for lesions greater than 500 μm deep.

Conclusions and relevance: Combined RCM-OCT imaging may be prospectively used to comprehensively diagnose lesions suggestive of BCC and triage for treatment. Further validation of this device must be performed on a larger cohort.

Figure 1.. Correlation of Basal Cell Carcinoma (BCC) Features on Reflectance Confocal Microscopy (RCM) With BCC Features on Optical Coherence Tomography (OCT)

A, The RCM en face image shows tumor nests at the dermal-epidermal junction (black asterisks). B, OCT image shows a roundish, hyporeflective structure (black asterisk) arising from the underside of the epidermis with clefting (yellow arrowheads) along with some dilated vessels in the dermis (white arrowheads). C, RCM en face image shows a central hair follicle surrounded by large tumor nests (black asterisks) with peripheral palisading and clefting on both sides. D, OCT image shows 2 large, gray tumor nests (black asterisks) encompassing the entire dermis.

Figure 2.. Combined Reflectance Confocal Microscopy (RCM)–Optical Coherence Tomography (OCT) for Detection of Residual Basal Cell Carcinoma (BCC) in a Previously Biopsied Lesion

A, A woman in her 80s had a slightly hyperpigmented papule with fine branching vessels on nasal ala. B, The RCM imaging at the level of the dermis showed branching horizontal vessels with leukocyte trafficking (white arrowheads) above an area with numerous small blood vessels between bright interweaving collagen bundles, which are distinct from background dermal collagen. Numerous adnexal structures (black asterisks) along with structures suggestive of tumor were observed. C, The OCT imaging showed a gray, branching tumor lobule with dark peritumoral rim in the dermis (red asterisk) along with structures suggestive of vellus hair follicles and some prominent vessels. D, Histopathologic examination (hematoxylin-eosin stain) confirmed the presence of tumor lobules in the dermis around the scar tissue (original magnification ×10).

Figure 3.. Combined Reflectance Confocal Microscopy (RCM)–Optical Coherence Tomography (OCT) for Basal Cell Carcinoma (BCC) Diagnosis in a Nonbiopsied Lesion

A, A woman in her 70s had a crusted, small, milky white to pink–colored papule on the nasal ala. B, The RCM imaging at the level of dermis showed a branching tumor nodule with subtle peripheral palisading and a dark peritumoral rim (black asterisk), prominent canalicular vessels with leukocyte trafficking (white arrowheads), and patchy mild inflammation (small round bright cells). C, The optical coherence tomography (OCT) imaging showed disruption in the normal epidermal and dermal patterns by ill-defined hyporeflective structures (red asterisk) throughout the entire field of view. D, Histopathologic examination (toluidine blue–stained) showed an intradermal tumor composed of branching lobules and cords of atypical basaloid cells with peripheral palisading and within the reticular dermis (original magnification ×10).

Figure 4.. Correlation Between Optical Coherence Tomography (OCT)–Estimated Depth and Histopathologically Measured Depth

A, High correlation was observed for combined lesions: R value was 0.86 and R² value was 0.75 (P < .001). B, High correlation was observed for lesions less than 500 μm deep: R value was 0.85 and R² value was 0.73 (P < .001). C, Moderate correlation was observed for lesions greater than 500 μm deep: R value was 0.65 and R² value was 0.43 (P < .001).