High-frequency ultrasound features of basal cell carcinoma and its association with histological recurrence risk

BACKGROUND: Due to advances in high-frequency ultrasound technology, it is easier to detect fine structures of skin lesions. The aim of this study was to examine the ultrasonographic features and use recurrence risk stratification to assess the diagnostic performance of pre-operative ultrasound examination of basal cell carcinoma (BCC). METHODS: This was a retrospective study. Forty-six BCC lesions underwent pre-operative ultrasound examination using 50- and 20-MHz probes. Ultrasonographic shape, margin, internal echoes, hyper-echoic spots, posterior echoes, and depth of the lesion were evaluated and correlated with the risk of recurrence based on histological features. RESULTS: Forty-two patients had 46 skin lesions in total. The high-risk (n = 6) and low-risk (n = 40) groups exhibited considerable overlap in the ultrasonographic manifestations and no significant difference in margin (χ(2) = 3.231, P = 0.072), internal echo (χ(2) = 1.592, P = 0.207), or posterior echo (P = 0.169). However, high-risk BCCs tended to be irregular in shape than low-risk lesions (χ(2) = 4.313, P = 0.038). Both types presented hyper-echoic spots (χ(2) = 1.850, P = 0.174). Additionally, 78% of low-risk lesions were confined to the dermis (31/40), and 100% of high-risk lesions infiltrated into the sub-cutaneous tissue, resulting in a significant difference between the two groups (χ(2) = 10.951, P = 0.001). Ultrasound detected sub-clinical lesions in five patients. CONCLUSIONS: High-frequency ultrasound can provide important information for pre-operative evaluation of risk in BCC foci and reveal hidden lesions. The technique may play a crucial role in guiding therapeutic options for BCC.