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.