Fast Evaluation of 69 Basal Cell Carcinomas With Ex Vivo Fluorescence Confocal Microscopy

Abstract

IMPORTANCE Fluorescence confocal microscopy (FCM) represents a first step toward a rapid "bedside pathology" in the Mohs surgery setting and in other fields of general pathology.OBJECTIVE To describe and validate FCM criteria for the main basal cell carcinoma (BCC) subtypes and to demonstrate the overall agreement with classic pathologic analysis of hematoxylin-eosin-stained samples. MAIN OUTCOMES AND MEASURESPresence or absence of BCC and histological subtype (superficial, nodular, and infiltrating) in the confocal mosaics. Eight criteria for BCC were described, evaluated, and validated.RESULTS Although there were minor differences among BCC subtypes, the most BCC-defining criteria were peripheral palisading, clefting, nuclear pleomorphism, and presence of stroma. These criteria were validated with independent observers (κ values >0.7 for most criteria).CONCLUSIONS AND RELEVANCE We herein propose, describe, and validate FCM criteria for BCC diagnosis. Fluorescence confocal microscopy is an attractive alternative to histopathologic analysis of frozen sections during Mohs surgery because large areas of freshly excised tissue can be assessed in real time without the need for tissue processing while minimizing labor and costs.

In Vivo and Ex Vivo Confocal Microscopy for Dermatologic and Mohs Surgeons

“…11–28 FCM criteria include the presence of the following: Fluorescence. Presence of fluorescence was determined when bright images were seen on the screen.…”

Advances in the use of Reflectance Confocal Microscopy in Melanoma

“…Ex vivo confocal microscopy is being introduced for assessment of surgical margins on freshly excised tissues, mostly of BCCs [102–104] but also for breast cancer core biopsies [105] and intraoperative assessment of conjunctival [106], breast [107] and brain tumors [108]. For this purpose, a fluorescence mode confocal microscope is used.…”

Implementation of fluorescence confocal mosaicking microscopy by “early adopter” Mohs surgeons and dermatologists: recent progress

“…mosaicking rapidly and reliably in an actual clinical setting for the evaluation of fresh ex vivo tissues. Later, Bennàssar et al 29 advanced the implementation and testing of FCM imaging in clinics by defining FCM criteria for all subtypes of BCC. This was a quintessential step to improve the reproducibility of BCC diagnosis and its differentiation from surrounding dermis and adnexal structures (especially small hair follicles) that often pose diagnostic dilemma.…”

“…The comparisons were independently evaluated by a dermatopathologist and demonstrated high overall concordance (κ ¼ 0.9) in classifying BCC subtypes. 29 In order to further validate the aforementioned FCM criteria, the same FCM images were also independently evaluated by two dermatologists. These criteria were validated with κ values greater than 0.7 for most criteria in both independent observers.…”

“…25,26 Confocal mosaicking microscopy (CMM) is currently the furthest advanced, being implemented and validated in Mohs surgical settings in real time. [27][28][29][30][31] In these settings, CMM is being integrated into the clinical workflow and has shown high sensitivity and specificity for detecting residual BCC tumors in fresh Mohs surgical excisions. In this article, we assess the progress of CMM-guided Mohs surgery from bench-top development in a laboratory to actual bedside implementation in Mohs surgical settings.…”