BACKGROUND: Biopsy specimens from patients with basal cell carcinoma (BCC) can present to surgery with no clinically residual tumor, complicating treatment decisions.

OBJECTIVE: To evaluate reflectance confocal microscopy (RCM) for the assessment of residual BCC following biopsy.

METHODS: Consecutive patients with biopsy-proven BCC and no clinical evidence of residual tumor who had been referred for Mohs micrographic surgery were included. Biopsy sites were imaged with a handheld RCM device. On the basis of RCM evaluation, cases were labeled RCM positive or RCM negative. Mohs micrographic surgery was performed in all cases; margins and 15-μm serial vertical sectioning were evaluated.RESULTS: A total of 61 patients were included (mean age, 61.7 years [standard deviation, 12.2 years]; range, 37-87 years); 60.7% were women. The mean lesion size was 5.1 mm (range, 3-12 mm); 73.8% of patients were positive on RCM, and 68.9% had residual BCC on histopathologic examination. The rates of RCM sensitivity, specificity, positive predictive value, and negative predictive value were 92.8%, 68.4%, 86.6%, and 81.2%, respectively. Three cases of BCC (high-risk, infiltrative, and basosquamous) were missed with use of RCM. When high-risk subtypes were excluded (n = 5), sensitivity and negative predictive value were both 100%.

LIMITATIONS: RCM can miss deep-seated residual tumor.

CONCLUSION: RCM is a valuable tool for the evaluation of residual BCC following biopsy, with the potential to reduce unnecessary surgical procedures.

Copyright © 2019 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

KEYWORDS: Mohs micrographic surgery; basal cell carcinoma; biopsy; dermoscopy; reflectance confocal microscopy; residual; surgery

PMID:31227277 PMCID:PMC6635070 [Available on 2020-08-01] DOI:10.1016/j.jaad.2019.02.049