Dermoscopic patterns of early-stage mycosis fungoides in a Chinese population

Early‐stage mycosis fungoides (eMF) is a clinical diagnostic challenge because it can mimic inflammatory diseases. Dermoscopy has been reported to be useful in evaluation of eMF in Caucasian patients; however, dermoscopic features of eMF in the Chinese population are lacking. To determine the validity of dermoscopy in the diagnosis and differential diagnosis of eMF in a Chinese population. This was a retrospective study that included a total of 101 patients with eMF (n = 31), chronic dermatitis (CD; n = 36) or plaque psoriasis (PP; n = 34) who were examined dermoscopically, histopathologically and immunohistochemically. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for predefined dermoscopic criteria in relation to the diagnosis of eMF. In addition, CD34 immunohistochemistry was used to visualize dermal vessels to correlate dermoscopic features with histological changes. Linear vessels (sensitivity 90.3%, specificity 92.9%), characteristic vascular structures resembling spermatozoa (sensitivity 74.2%, specificity 100%) and orange‐yellowish patchy areas (sensitivity 90.3%, specificity 91.4%) were highly predictive for the diagnosis of eMF compared with CD and PP. Dermoscopy shows great value in the diagnosis and differential diagnosis of eMF in a Chinese population.