The preoperative diagnostics of malignant melanoma - Comparison of 7.5-MHz- and 20-MHz-sonography

Aim: High-frequency sonography has become extremely helpful for the preoper ative assessment of malignant melanoma. The purpose of this study was to co mpare the preoperative vertical tumour thickness as assessed by 7.5 MHz as well as 20 MHz ultrasound probes to the postoperative tumour thickness as d etermined histomorphometrically. Methods: 249 patients with malignant melan oma were studied using a conventional 7.5 MHz ultrasound machine (since 198 7) or a high-frequency 20 MHz ultrasound imaging system (since 1991). Resul ts: The correspondence of the sonographically assessed tumour thickness wit h the thickness assessed by histomorphometry was significantly better for h igh-frequency sonography (r=0.94) as compared to conventional sonography(r= 0.76). For stages pT(3) and pT(4), however, this difference was not signifi cant. Conclusion: Based on these data, high-frequency sonography should be given preference in the preoperative assessment of malignant melanoma over conventional 7.5 MHz ultrasound. However, for stages pT(3) and pT(4) both m ethods offer similarly reliable results.