A positive SLN in thin melanomas is uncommon with a prevalence of 4.1% in our study population. We could not identify reliable clinicopathological risk factors which could predict results of SLNB in thin melanomas. Based on our results, SLNB may be considered in patients with a melanoma of thickness in the range 0.90-0.99 mm, because all SLN-positive patients belonged to this subgroup.

On the basis of our follow-up data, SLNB has to be recommended in patients with a tumour thickness >4.00 mm after exclusion of lymph node macrometastases or distant metastases. SLN status is the most significant prognostic factor in this group of patients.