Examination of the clinical and dermoscopic features of mixed-type basal cell carcinoma cases

Basal cell carcinoma (BCC) is a malignant skin tumor thought to develop from epidermal basal cells or the outer root sheath of hair follicles. Identifying the histopathological subtype can guide treatment selection and patient follow-up. While histopathological examination is the gold standard for subtype determination, dermoscopic examination can also be helpful. Dermoscopic findings related to histopathological subtypes in BCC have been identified, but the changes in these dermoscopic features in mixed-type BCC combinations remain unclear. This study aims to examine the demographic characteristics of patients diagnosed with single and mixed-type BCC histopathologically in our clinic and investigate the correlation between clinical and dermoscopic findings and histopathological subtypes. For this purpose, adult patients in our center who were diagnosed with BCC through histopathological analysis following total excision, with dermoscopic findings systematically recorded through photographic documentation, were included in the study. A total of 186 BCC lesions from 157 patients, with a mean age of 68.8±12.7 years (range: 30–94), were evaluated. The most frequent lesion location was the head and neck region (74.7%), and the histopathological subtypes were nodular (42.5%), mixed (37.6%), superficial (12.4%), basosquamous (3.2%), infiltrative (2.7%), micronodular (1.1%), and fibroepithelial (0.5%). Among mixed-type BCCs, the most common histopathological subtype combinations were nodular-infiltrative (32.9%) and nodular-superficial (31.4%). In dermoscopy, short fine telangiectasia (p<0.001), yellow-white structureless areas (p=0.023), scales (p=0.020), and rosette structures (p=0.003) were observed more frequently in mixed-type lesions than in single-type lesions. In contrast, corkscrew vessel patterns were more prevalent in single-type lesions (p=0.048). The presence of a superficial histopathological component in mixed-type lesions was associated with an increased wheel-like structure in dermoscopy, while the presence of an infiltrative component was associated with dotted and glomerular vessel patterns, and basosquamous components were linked to arborizing vessel patterns. Additionally, in mixed-type BCCs, the dermoscopic findings of arborizing vessel patterns (p=0.019) and dotted vessel patterns (p=0.025) were associated with high-risk subtypes. In conclusion, our study suggests that dermoscopic findings may serve as a guide in recognizing mixed-type BCC lesions, distinguishing subtype components, and assisting in treatment decision-making based on these observations. Keywords: Basal cell carcinoma (BCC), dermoscopy, mixed-type BCC.