Reflectance confocal microscopy for Kaposi's sarcoma treatment monitoring after intralesional vincristine chemotherapy

Kaposi's sarcoma (KS) is a multifocal systemic disease, originating from endothelial cells mainly affecting elderly men. Intralesional chemotherapy with vinblastine or vincristine is an effective and well‐tolerated treatment in patients presenting single nodules on the skin. Despite reflectance confocal microscopy represents a useful diagnostic method for many dermatological diseases, to date, there are few data regarding the use of RCM in mucocutaneous KS. Objective of this study was to evaluate the use of RCM for therapeutic follow‐up in KS patients treated with intralesional vincristine. An observational retrospective study involving patients with a histological diagnosis of classic KS was conducted. All patients were treated with intralesional vincristine; reflectance confocal microscopy images were taken for each patient at baseline (T0) and 1 month after vincristine injection. Four male patients with a median age of 76.8 years were included in the study and four nodules (one for each patient) were evaluated with RCM examination before and after vincristine injections. At 1 month from intralesional vincristine treatment, therapeutic response was confirmed at RCM examination; a reduction of inflammatory cell at the stratum spinosum level in all evaluated lesions was observed; at papillary dermis levels, black luminal structures were decreased in diameter and superficial linear canalicular structures were not represented. Aggregates of inflammatory cells and of hemosiderin deposition, at the dermal level, were reduced in number. Reflectance confocal microscopy showed to be a promising method to evaluate vincristine therapeutic response in patients with KS; further studies evaluating RCM use in KS patients in order to monitor treatment efficacy are still required.