Usefulness of real-time tissue elastography for detecting the border of basal cell carcinomas

Preoperative evaluation of tumor thickness and silhouette in basal cell carcinoma (BCC) is one of the important assessments to be done. However, evaluation is not always sufficient even utilizing sonography and magnetic resonance imaging. Recently, a new technique called real-time tissue elastography (RTE) was developed that can display the hardness of tissue as a color overlay of a sonographic image. Therefore, RTE could be used as a tool for detecting the tumor border according to differences in tissue rigidity. In the present study, the correlation between histopathological and RTE tumor thickness measurements was evaluated for BCC. Eleven BCC (six nodular, three superficial, and two adenoid or cystic) from individual patients were evaluated. Tumor silhouette and thickness were detected using conventional B-mode sonography and RTE. All lesions were surgically excised and tumor thickness was also examined histologically. In the six nodular BCC, the tumor silhouette determined by RTE showed a close correlation with the results of histopathology. Particularly, for four out of the six cases, the correlation was excellent. In addition, the mean difference in tumor thickness measurements between histology and RTE (-0.368 mm) was lower than that between histology and B-mode sonography (-0.835 mm). As for the superficial BCC, tumor thickness was too thin to evaluate. Tumor thickness measured by B-mode sonography and RTE was identical for two cases of adenoid or cystic BCC. In conclusion, RTE is useful in the preoperative assessment of tumor thickness, especially with the nodular type of BCC, and allows us to determine adequate surgical margins.