Sentinel node biopsy and ultrasound scanning in cutaneous melanoma: clinical and technical considerations

The aim of this study was to discuss the role of preoperative ultrasound (US) scanning and sentinel node biopsy (SNB) in melanoma patients. 100 patients underwent SNB following preoperative US scan and lymphoscintigraphy; patent blue dye (PBD) was injected before biopsy. Intra-operative lymphoscintigraphy (IL) was performed in 51 basins. All nodes were examined with histology and immunohistochemistry. Sensitivity and specificity of US scanning was 33% and 100%, respectively; 7% were true positives. The low sensitivity was mainly due to the resolution power of the US scanner (2 mm) which was unable to identify all the patients with microdeposits. PBD associated with IL identified SNs in all cases. In all patients with Breslow >1.5 mm and in all cases with two metastatic SNs, further positive additional nodes were found. The mean counts per 10 s (CP10S) ratio for SN and non-SN values was 5.62 (1.29-23.51) and 3.09 (1.03-10.99) in the intra-operative and extra-operative phases, respectively. US scanning and preoperative lymphoscintigraphy associated with PBD allows preoperative patient selection and accurate SN(s) identification. Breslow thickness and the number of metastatic SN(s), but not their type, are correlated with disease spread; CP10S contributed to the differentiation amongst the nodes and the determining of procedure's completion.