Ex Vivo High-Frequency Ultrasound of the Skin in the Morphologic Assessment of Basal Cell Carcinoma: A Comparative Study

Background/Objectives: Noninvasive imaging of the skin in the assessment of basal cell carcinoma (BCC) is a promising field of research. Ultrasound stands out because of its ease of use, low price point and versatility. Ex vivo ultrasound can be used to obtain detailed measurements of tumor size, depth and margin assessment. These measurements can be compared with histopathological measurements. Methods: We performed a prospective study on formaldehyde-fixed tissue samples at the Pathology Department of Timisoara County Hospital. A total of 19 consecutive basal cell carcinomas from 17 patients were included in the study. Results: The study cohort was predominantly male (76.5% versus 23.5%), with a median age of 73 years (interquartile range: 62–77 years). Most lesions were excised from the head and neck region (84.2%) and were primarily classified as nodular (42.1%) and infiltrative (36.8%) subtypes by histopathological assessment. Bland–Altman analysis comparing ultrasound measurements to histopathology revealed no statistically significant systematic or proportional bias for tumor depth and deep margin measurements; however, the limits of agreement were wide for all three parameters: tumor depth (−3.35 to +3.77 mm), deep margin (−3.36 to +2.65 mm), and maximum diameter (−17.32 to 14.55 mm). Statistically significant proportional bias was observed in ultrasound-based assessments of tumor size. An additional exploratory analysis evaluated the diagnostic accuracy of ex vivo ultrasound in identifying tumors with invasion depths exceeding 2 mm relative to histological analysis. Conclusions: Our results suggest that ex vivo HFUS at 22 MHz is not interchangeable with histopathology. Nevertheless, the results reported in this pilot study will be useful to inform future research and will serve as a framework for reporting HFUS results in dermato-oncology.