Background  Sentinel lymph node excision (SLNE) for the detection of regional nodal metastases and staging of malignant melanoma has resulted in some controversies in international discussions as it is a surgical intervention with potential morbidity.

Objective  The present retrospective study seeks to clarify the reliability of preoperative ultrasonography (US) in direct comparison to the result of SLNE and seeks to identify potential advantages of preoperative ultrasound if performed in conjunction with lymphoscintigraphy in detecting malignant melanoma metastases in sentinel lymph node (SLN).

Patients  We retrospectively analysed data from 221 patients with primary malignant melanoma with a Breslow index of ≥1.0 mm.

Results  Of the 221 patients, 77.4% (= 171) had a negative SLN. In 50 patients (22.6%), the histopathological investigation of 71 excised lymph nodes resulted in a positive SLN. The US examination demonstrated a sensitivity of 13.6%, a specificity of 96.9%, a positive predictive value of 97.2% and a negative predictive value of 12.6%. SLNE alone shows a sensitivity of 94%, a specificity of 98.6%, a positive predictive value of 100% and a negative predictive value of 98.3%. Preoperative US in conjunction with dynamic lymphoscintigraphy, followed by SLNE, demonstrated a detecting ratio of 100% (= 28) for micrometastases and 98.6% (= 42/43) for macrometastases.

Conclusion  In conclusion, this study confirms that preoperative US alone cannot replace the vital information obtained during dynamic lymphoscintigraphy. But preoperative US is an important component of the staging procedure in melanoma patients and has clear advantages when performed in conjunction with dynamic lymphoscintigraphy. Therefore, we recommend preoperative US before every SLNE.