Dermoscopy Combined with Reflectance Confocal Microscopy As a Noninvasive Involvement for Monitoring Cutaneous Rosai-Dorfman: A Case Report.

Cutaneous Rosai-Dorfman disease(CRDD) is an extremely rare entity and features histiocytic proliferation in the skin. Dermoscopy and reflectance confocal microscopy(RCM) reports on CRDD are rare. We reported a case of CRDD and summarized the dermoscopy(FotoFinder Medicare 800HD, FotoFinder-Systems GmbH, Birbach Germany) and RCM(VivaScope® 1500, V Caliber Imaging and Diagnostics) features of CRDD. The dermoscopic features of CRDD showed red-orange background with pale yellowish roundish areas similar to millet, surrounded by branched blood vessels. Sometimes the white structureless materials of CRDD could be observed by dermoscopy, which may be a hint of spontaneous regression. The RCM features of CRDD revealed dense highly refractile roundish or ovoid structures(inflammatory cells), and multiple larger structures with central low refraction and moderately refractive peripheral semicircle or circle(engulfed inflammatory cells), together with low refractive branched structures(blood vessels). Dermoscopic and RCM features of CRDD can help the dermatologists recognize and follow-up the disease in real time.