[Preoperative sonographic diagnosis of melanoma--comparison of 7.5- and 20-MHz sonography]. / Präoperative sonographische Melanomdiagnostik--Vergleich von 7,5- und 20-MHz-Sonographie.

AIM: High-frequency sonography has become extremely helpful for the preoperative assessment of malignant melanoma. The purpose of this study was to compare the preoperative vertical tumour thickness as assessed by 7.5 MHz as well as 20 MHz ultrasound probes to the postoperative tumour thickness as determined histomorphometrically. METHODS: 249 patients with malignant melanoma were studied using a conventional 7.5 MHz ultrasound machine (since 1987) or a high-frequency 20 MHz ultrasound imaging system (since 1991). RESULTS: The correspondence of the sonographically assessed tumour thickness with the thickness assessed by histomorphometry was significantly better for high-frequency sonography (r = 0.94) as compared to conventional sonography (r = 0.76). For stages pT3 and pT4, however, this difference was not significant. 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 pT3 and pT4 both methods offer similarly reliable results.

[Ranking of 20 MHz sonography of malignant melanoma and pigmented lesions in routine diagnosis]. / Stellenwert der 20-MHz-Sonographie des malignen Melanoms und pigmentierter Läsionen in der Routinediagnostik.

PURPOSE: Eleven dermatology clinics from all over Germany took part in our multicenter prospective study with the aim of evaluating 20 MHz sonography in the preoperative diagnosis of malignant melanomas and other pigmented skin tumours. It was to be assessed how effective sonographic measurement of thickness would compare to histology and the clinical palpation of tumour thickness and also the significance of differential diagnosis in sonography of malignant melanomas. METHOD: The prospective multicenter study proceed as follows. To the end of August 1997 264 patients with a primary malignant melanoma and 417 patients with benign skin tumours were examined via 20 MHz sonography. Two different examiners estimated the clinical thickness of the tumour by palpation. The tumour was then excised and examined for postoperative correlation with the histology sections. RESULTS: The final results showed good correlation between the histological and sonographic estimation of tumour thickness (r = 0.97). Estimation of tumour thickness by palpation showed no correlation with the histology (r = 0.59). Most of the benign (44%) and malignant tumours (38.7%) were spindle shaped. There was no significant difference between the benign and malignant tumour groups in relation to the sonographic presented shapes or echo signs. No different diagnosis could be made. CONCLUSION: The technique of high frequency sonography in relation to preoperative diagnosis of malignant melanomas has high priority. In contrast to clinical estimation of tumour thickness, sonography provided a good correlation to histology. The effectiveness of sonography with regard to the valence of the skin tumours is limited and there is no possibility of differentiating between malignant and benign tumours from the morphological face value. Hence, there is a demand for developing a 150 MHz apparatus which will be able to supply evidence regarding the valence of skin tumours.