5a Trichoepithelioma
March 2008
TLDR Trichoepithelioma and desmoplastic trichoepithelioma have distinct features that can be identified using reflectance confocal microscopy.
Reflectance confocal microscopy (RCM) was used to identify features of trichoepithelioma (TE) and desmoplastic trichoepithelioma (DTE) that were similar to those seen in histology. TE showed tumor islands with knobby extensions and peripheral palisading of basaloid cells, resembling basal cell carcinoma. These tumor islands were wrapped in a brightly refractile stroma, creating an 'onion skin' appearance. DTE displayed smaller tumor cell nests and cords within a sclerotic stroma. Both TE and DTE contained tricholemmal horn cysts. A clinical case involved a 60-year-old woman with a 3 mm papule on her forehead, showing a milk-white hue and telangiectatic vessels under dermoscopy.
