Objectives: Basal cell carcinoma (BCC) is the most common dermatologic malignant skin cancer. Infiltrative histologic variants are more aggressive and require wider surgical margins or Mohs surgery, in contrast with noninfiltrative variants, which are commonly treated with standard surgical excision. Elastography has not been used to date to differentiate between the histologic variants of BCC. The purpose of this study was to differentiate infiltrative from noninfiltrative BCCs on elastography.
Methods: A total of 31 facial BCCs were studied. Preoperatively, color Doppler ultrasound and strain elastographic examinations of the lesions were performed. The size, intralesional vascularization, and presence of hyperechoic dots were considered relevant B-mode and color Doppler variables. Strain ratios of the tumors were obtained with respect to adjacent healthy tissue. Increased marginal stiffness, which was considered hardness in greater than 50% of the tumor margin, was also blindly evaluated. Histologic confirmation and subtyping (infiltrative or noninfiltrative) were performed in all cases.
Results: Infiltrative BCCs did not differ in the size, presence or absence of hyperechoic dots, or vascularization from noninfiltrative BCCs. Strain ratios were similar in both infiltrative and noninfiltrative BCCs (mean ± SD, 1.82 ± 0.879 versus 2.2 ± 1.11). However, infiltrative BCCs had statistically increased marginal stiffness in comparison with noninfiltrative BCCs (88.0% versus 18.8%). Increased marginal stiffness had sensitivity and specificity of 0.89 and 0.82 respectively, with a positive predictive value of 0.67 for infiltrative BCCs and a negative predictive value of 0.95 for noninfiltrative BCCs.
Conclusions: Histologic variants of BCC have different elastographic patterns. These differences may be of help in preoperative assessments of the BCC subtype and specific surgical planning, avoiding unnecessary skin biopsies.
Keywords: basal cell carcinoma; dermatologic elastography; dermatologic ultrasound; elastography.
© 2018 by the American Institute of Ultrasound in Medicine.