Accuracy of in vivo confocal microscopy for diagnosis of basal cell carcinoma: a comparative study between handheld and wide-probe confocal imaging.

BACKGROUND: Reflectance confocal microscopy (RCM) increases specificity of identification of basal cell carcinoma (BCC). A smaller-diameter handheld RCM (HH-RCM) allows better access to limited anatomic locations. OBJECTIVE: To compare accuracy of HH-RCM in identification of BCC to that of traditional wide-probe RCM (TWP-RCM). METHODS: Patients presenting at least one lesion clinically and dermoscopically suspicious for BCC, were recruited from two dermatology skin cancer clinics. Prior to excision, we attempted to image all lesions with HH-RCM and TWP-RCM using a standardized protocol. RCM images were retrospectively evaluated, jointly by two blinded readers. For purposes of comparative RCM, sensitivity and specificity analysis, we used a threshold of ≥3 RCM criteria to identify BCC, whereby at least one criterion had to be presence of 'dark silhouettes' or 'bright tumor islands'. RESULTS: Among 54 lesions imaged with both RCM devices, 45 were biopsy-proven BCCs. Comparison between TWP-RCM vs. HH-RCM was as follows: sensitivity (100% vs. 93%), specificity (78% for both probes), positive predictive value (96% vs. 95%), and negative predictive value (100% vs. 70%) respectively. Notably, both TWP-RCM and HH-RCM demonstrated the presence of 'dark silhouettes' or 'bright tumor islands' in all 45 BCCs. CONCLUSION: Both RCM probes demonstrate high PPV. TWP-RCM shows higher NPV, since its broader field-of-view probably allows more exhaustive search for BCC criteria. The RCM criteria threshold for BCC identification should be further tested.

Use of handheld reflectance confocal microscopy for in vivo diagnosis of solitary facial papules: a case series.

BACKGROUND: Reflectance Confocal Microscopy (RCM) can be useful for evaluation of solitary pink papules that are suspicious for skin cancer. RCM has been challenging to apply to curvy facial areas because of the need for attaining full contact between the skin and RCM probe. A smaller diameter handheld RCM probe has been recently introduced to clinical practice. OBJECTIVE: To describe the utility of RCM handheld probe as a bedside adjunct for clinical diagnosis of solitary facial papules. METHODS: This is a retrospective descriptive case series of six patients presented with a diagnostically equivocal solitary facial papule. All lesions reported were evaluated and imaged clinically, dermoscopically and with handheld RCM, followed by biopsy for histopathological analysis. RESULTS: The series included biopsy-proven basal cell carcinomas (BCCs) (n = 2), squamous cell carcinoma (n = 1), sebaceous hyperplasia (n = 1), desmoplastic trichoepithelioma (n = 1) and compound nevus (n = 1). Handheld RCM was easy to apply to the curved facial surfaces and allowed for reaching a correct bedside diagnosis. CONCLUSION: For clinically and dermoscopically equivocal small papules on curved facial surfaces, handheld RCM may be particularly helpful in differentiating benign lesions from skin cancer.