Pigmented nodular Basal cell carcinomas in differential diagnosis with nodular melanomas: confocal microscopy as a reliable tool for in vivo histologic diagnosis.

Nodular basal cell carcinoma, especially when pigmented, can be in differential diagnosis with nodular melanomas, clinically and dermoscopically. Reflectance confocal microscopy is a relatively new imaging technique that permits to evaluate in vivo skin tumors with a nearly histological resolution. Here, we present four cases of challenging nodular lesions where confocal microscopy was able to clarify the diagnosis.