Diagnostic value of reflectance confocal microscopy combined with dermoscopy for melanocytic nevus / 中华皮肤科杂志

ABSTRACT

Objective To evaluate the diagnostic value of dermoscopy and reflectance confocal microscopy (RCM) alone or in combination for melanocytic nevus.Methods A total of 37 patients with clinically diagnosed melanocytic nevus were collected.Skin lesions were firstly examined by dermoscopy and RCM,then were resected to be subjected to histopathological examination for final diagnosis.The imaging features of melanocytic nevus were summarized.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of different skin imaging techniques were calculated,and the consistency was analyzed between skin imaging techniques and histopathological examination.Results Based on the dermoscopic and RCM findings,2 kinds of nevus cells with different morphological features were observed in the dermis of intradermal nevus.One kind of nevus cells was characterized by a nonfusional,highly-refractive round structure in the papillary dermis under RCM,and by a brown or light brown homogenous pattern under dermoscopy,which was observed in 5 skin lesions.The other kind of nevus cells appeared as irregular,highly-refractive cell clumps in the papillary dermis under RCM,and by a cobblestone or globular pattern under dermoscopy,which was observed in 31 skin lesions.For the diagnosis of melanocytic nevus,the sensitivity,specificity,accuracy,positive predictive value and negative predictive value of RCM combined with dermoscopy were 91.7％,87.5％,90.9％,97.1％ and 70％ respectively,those of RCM were 86.1％,75％,84％,93.9％ and 54.5％ respectively,and those of dermoscopy were 77.8％,87.5％,75％,96.3％ and 41.2％ respectively.All the diagnostic indices of RCM combined with dermoscopy were higher than those of RCM or dermoscopy alone,except that the specificity was equal to that of dermoscopy alone.RCM showed higher sensitivity,accuracy and negative predictive value,but lower specificity and positive predictive value compared with dermoscopy.There were no significant differences in the diagnostic yield in melanocytic nevus between RCM combined with dermoscopy or RCM alone and histopathological examination (x2 =0.25,0.57,P =0.63,0.45,Kappa value =0.72,0.53,respectively).However,a significant difference in the diagnostic yield in melanocytic nevus was observed between dermoscopy and histopathological examination (x2 =5.81,P =0.012).Conclusion RCM combined with dermoscopy shows higher diagnostic accuracy for melanocytic nevus compared with RCM or dermoscopy alone.