Abstract: Objective: To investigate the image features of multiple basal cell carcinoma (BCC) under reflectance confocal microscopy (RCM), and further assess the application value of RCM in the diagnosis and follow-up of multiple BCC. Methods: Among 6 patients (64 lesions) clinically diagnosed as BCC, 62 lesions were diagnosed as BCC by RCM. Of 62 lesions, 39 were taken surgical treatment and histopathologic examination, 23 were treated with 5% imiquimod cream. 62 lesions were re-assessed by RCM during follow-up. The RCM image characteristics of BCC were summarized. Results: The histological features of 39 lesions treated with excision were in accordance with BCC and the coincidence rate of diagnosis was 100％. No RCM evidence of BCC was identified at 3-month and 6-month follow-up. Of 23 lesions treated with 5% imiquimod cream,  there were RCM evidence of BCC in 12 lesions, 8 lesions and 4 lesions respectively at 3-month, 6-month and 12-month follow-up. The RCM characteristics of 62 lesions were keratinocyte atypia (96.8%), tumor islands (96.8%), cords connected to the epidermis (90.3%), bright particles inside and around tumor island (77.4%), peripheral palisading (51.6%), peri-tumoral clefting (54.8%), increased vascularization (95.2%), dendritic cells inside tumor islands (77.4%). Conclusion: There are characteristic RCM features of BCC, and RCM play an important role in follow-up diagnosis.

Key words: basal cell carcinoma, reflectance confocal microscopy, imiquimod