Reflectance Confocal Microscopy Features of Focal Dermal Mucinosis Differ from Those Described for Basal Cell Carcinoma: Report of Two Cases

Abstract

The purpose of this study was to describe the reflectance confocal microscopy (RCM) features of focal dermal mucinosis (FDM). The entity clinically and dermatoscopically mimics other diagnostic entities, most notably nonpigmented basal cell carcinoma. We describe two cases that highlight the dermatoscopic, RCM and histopathological attributes of FDM. RCM features such as dermal foci of dense collagen bundles oriented in the same direction, foci of haphazardly oriented thin collagen fibers separated by dark structureless areas and the absence of dark silhouettes and tumor islands are clues for FDM diagnosis. The FDM cases described here present consistent and particular RCM findings that appear to correlate well with the histopathological features of FDM. Therefore, RCM is a promising technology in diagnosing skin lesions and it use can avoid invasive procedures.

Lichen myxedematosus: a rare group of cutaneous mucinosis

“…Although the number of patients in this study was small, and more studies are needed to standardize patterns on RCM in dermal mucinoses, RCM may be a promising method for diagnosis. 43…”

Reflectance confocal microscopy of mammary Paget disease

“…Paget cells contain intracytoplasmic mucin [ 9 – 12 ], a mixture of acid mucopolysaccharides. Fraga-Braghiroli et al have shown that mucin located areas in dermal mucinosis were seen as darker areas on RCM [ 13 ]. Likewise, Ulrich et al have shown that the peritumoral cleft-like spaces seen in BCC on histopathology exist in vivo, and correspond to the peritumoral mucin deposition which also demonstrates that mucin appear dark on RCM [ 14 ].…”