Dermoscopic Features of Superficial Non Pigmented Basal Cell Carcinoma Following Cryotherapy as a New Diagnostic Criteria

Abstract

Non-pigmented superficial basal cell carcinoma (BCC) appear as thin, pink, scaly macule which differential diagnosis can be very broad. Cryotherapy is a valid therapeutic option; however studies of dermoscopic features of BCC after cryotherapy are scant. Objectives The current study aims to evaluate early dermoscopic signs of non-pigmented superficial BCC modification after cryosurgery. Methods. Prospective investigation was conducted from 2019 to 2020 with 33 participants with clinical features of superficial non pigmented BCC in the initial stage (erythematous macule or patch). The dermoscopic photos of all neoplasms firstly was made, then all patients underwent liquid nitrogen irrigation. The cryo-tip was placed at the distance of 5-10 mm from the skin surface, liquid nitrogen was directed to the center of the neoplasm to be treated 10 times (exposures). In 12-24 hours after the procedure the second dermoscopy was conducted for fixing the dynamic of the lesions. Formation of the translucent/pearl papules in the periphery of the lesions considered as a positive test result. The last step of research was a diagnostic biopsy performed for all participants. Results. There were 33 patients (19 males and 14 females, middle age was 61,7 years) with clinical features of BCC. The diagnostic biopsy allowed verify the diagnosis of BCC in 18 patients, 9 patients had a squamous cell carcinoma (SCC) and 6 patients had actinic keratosis (AK). Assessment of the dermoscopic features in 12–24 hours after irrigation of the lesion with liquid nitrogen allowed to detect the formation of translucent/pearl papules in the periphery of the lesion in 16/18 patients with BCC. 7/9 patients with SCC had negative result; other 2 patients had a nonspecific result. All patients with AK showed negative result. Thus, the specificity of the test was 88.24%, sensitivity - 88.89%, positive predictive value - 88.89%, negative predictive value - 78.94%.

Conclusions. The appearance of pearlescent and translucent papules at the periphery of the lesions characterize the dermoscopic picture of non-pigmented superficial BCC 12 hours after cryotherapy. Based on these data, the test can be considered as valid and practically applicable.