Reflectance confocal microscopy as a tool for screening surgical margins of basal cell carcinoma

Surgical excision of basal cell carcinoma with minimum margins requires serial assessment of layers by frozen histopathology in the case of Mohs micrographic surgery. Evaluation of presurgical tumor margins by in vivo reflectance confocal microscopy is a potential alternative. We selected 12 basal cell carcinoma lesions that were analyzed by confocal microscopy to define margins. The lesions were excised by Mohs surgery. Six tumors showed negative margins in the first phase of Mohs micrographic surgery. We concluded that reflectance confocal microscopy can be useful in the preoperative definition of basal cell carcinoma margins.     

Detection of basal cell carcinomas in Mohs excisions with fluorescence confocal mosaicing microscopy

Background High‐resolution real‐time imaging of human skin is possible with a confocal microscope either in vivo or in freshly excised tissue ex vivo. Nuclear and cellular morphology is observed in thin optical sections, similar to that in conventional histology. Contrast agents such as acridine orange in fluorescence and acetic acid in reflectance have been used in ex vivo imaging to enhance nuclear contrast. Objectives To evaluate the sensitivity and specificity of ex vivo real‐time imaging with fluorescence confocal mosaicing microscopy, using acridine orange, for the detection of residual basal cell carcinoma (BCC) in Mohs fresh tissue excisions. Methods Forty‐eight discarded skin excisions were collected following completion of Mohs surgery, consisting of excisions with and without residual BCC of all major subtypes. The tissue was stained with acridine orange and imaged with a fluorescent confocal mosaicing microscope. Confocal mosaics were matched to the corresponding haematoxylin and eosin‐stained Mohs frozen sections. Each mosaic was divided into subsections, resulting in 149 submosaics for study. Two Mohs surgeons, who were blinded to the cases, independently assessed confocal submosaics and recorded the presence or absence of BCC, location, and histological subtype(s). Assessment of confocal mosaics was by comparison with corresponding Mohs surgery maps. Results The overall sensitivity and specificity of detecting residual BCC was 96·6% and 89·2%, respectively. The positive predictive value was 92·3% and the negative predictive value 94·7%. Very good correlation was observed between confocal mosaics and matched Mohs frozen sections for benign and malignant skin structures, overall tumour burden and location, and identification of all major histological subtypes of BCC. Conclusions Fluorescent confocal mosaicing microscopy using acridine orange enables detection of residual BCC of all subtypes in Mohs fresh tissue excisions with high accuracy. This observation is an important step towards the long‐term clinical goal of using a noninvasive imaging modality for potential real‐time surgical pathology‐at‐the‐bedside for skin and other tissues.     

Reflectance confocal microscopy: Melanocytic and nonmelanocytic

Reflectance confocal microscopy (RCM) is a noninvasive imaging tool that has the potential to revolutionize dermatology. Extensive research in this area in conjunction with the recent assignment of reimbursement codes has made the clinical use of this technology a practical reality. Though there is awareness and use of this technology at large academic centers, a knowledge gap still remains in interpreting RCM images among the dermatology community. We review the key RCM features of melanocytic and nonmelanocytic lesions to provide guidance in distinguishing benign entities from malignant dermatologic neoplasms.     

Effectiveness and limitations of reflectance confocal microscopy in detecting persistence of basal cell carcinomas: a preliminary study

Background/Objectives: Reflectance confocal microscopy (RCM) can accurately and non‐invasively diagnose basal cell carcinoma (BCC). The use of RCM in assessing responses to saucerization or curettage and cautery of BCC has not been established. The aim of the present study was to expound the usefulness of RCM in assessing treatment responses of BCC to saucerization or curettage and cautery 8–12 weeks after treatment. Methods: Eight sequential patients, with 11 superficial BCCs, were recruited. Lesions were evaluated clinically and dermoscopically. Three operators performed RCM imaging for each BCC at baseline and 8–12 weeks after treatment. Diagnostic criteria for RCM diagnosis included streaming of basal cells and the presence of cord‐like structures and horizontal vessels. Results were compared against histopathology. Difficulties in establishing tumour clearance were identified and the effectiveness of RCM in assessing the response to treatment was explored. Results: At baseline, all lesions were consistent with superficial BCC. At 8–12 weeks after treatment, RCM correctly diagnosed 10 of 11 lesions as tumour free. Furthermore, RCM was reliable across operators of variable experience and the findings were confirmed histopathologically. Limitations were identified, but appeared to be related to operator experience. Conclusion: The diagnosis of BCC was straightforward and reliable in the present study. Thus, RCM appears useful in assessing the early treatment response of superficial BCC treated with saucerization or curettage and cautery despite operator‐dependant limitations.     

Long‐term therapy of multiple basal cell carcinomas: Clinicodermoscopic score for monitoring of intermittent vismodegib treatment

Vismodegib treatment of multiple basal cell carcinomas (BCCs) is limited by adverse effects and high relapse rates: intermittent regimens are therefore preferred for long‐term administration. The objective of this study was to investigate clinical and dermoscopic changes in BCCs during long‐term intermittent treatment and to identify those most indicative of tumor persistence/clearing. Clinical and dermoscopic images (n = 380 each) of 38 BCCs were acquired at 10 observation times (t0–t9). Biopsies were performed at baseline (t0) and after 72 weeks of treatment (t9). All images were evaluated retrospectively by experts who assessed the presence/absence of 12 clinical and 14 dermoscopic features: clinical scores (CScs) and dermoscopic scores (DScs) were then calculated.     

Reflectance confocal microscopy for cutaneous infections and infestations

Reflectance confocal microscopy (RCM) is a high‐resolution emerging imaging technique that allows non‐invasive diagnosis of several cutaneous disorders. A systematic review of the literature on the use of RCM for the study of infections and infestations has been performed to evaluate the current use of this technique and its possible future applications in this field. RCM is particularly suitable for the identification of Sarcoptes scabies, Demodex folliculorum, Ixodes, Dermatophytes and Candida species in the clinical practice and for the follow‐up after treatment. The cytopathic effect of herpes simplex virus, varicella zoster virus and molluscipoxvirus is also detectable by this imaging technique even in a pre‐vesicular stage. In addition, thanks to its non‐invasiveness, RCM allows pathophysiological studies.