High Frequency Ultrasound of Basal Cell Carcinomas: Ultrasonographic Features and Histological Subtypes, a Retrospective Study of 100 Tumors

(1) Background: 22 MHz high frequency ultrasound (HFUS) is a non-invasive imaging technique that gives information on depth, length, volume and shape of skin tumors. (2) Methods: We reviewed the clinical, ultrasound, and histological records of 54 patients with 100 histologically confirmed basal cell carcinoma (BCC) tumors with the use of HFUS. (3) Results: Most infiltrative tumors (n = 16/21, 76.2%) were irregular shaped, followed by five (23.8%) being round shaped; most superficial tumors (n = 25/29, 86.2%) were ribbon shaped, followed by four (13.8%) being round shaped; most nodular tumors (n = 26/33, 78.8%) were round shaped, followed by seven (21.2%) that were irregular shaped; and, lastly, all microdular tumors (n = 2/2, 100%) were round shaped. Strong evidence of association (p = 0.000) was observed between the histological subtype and tumor shape as seen using the HFUS. No evidence of association was found between the histological subtype and tumor margin (p > 0.005). Cohen's Kappa statistic to assess the agreement between BCC subtypes evaluated by histological examination and U/S appearance was calculated equal to 0.8251 (almost perfect agreement). (4) Conclusions: HFUS appears to be a reliable technique for the pre-operative evaluation of BCCs, assisting physicians to decide on the optimal therapeutic approach.