Clinical Significance of Intra-nodal Naevi in Sentinel Node Biopsies for Malignant Melanoma

BACKGROUND: Intra-nodal naevi (INN) identified during assessment of a sentinel lymph node for melanoma are not an uncommon finding. Little is known about their clinical significance. Patients with INN are treated as sentinel node biopsy (SNB) negative currently. Our aim was to assess the significance of INN in patients who undergo SNB for melanoma. METHODS: 353 melanoma patients who underwent a SNB between November 1999 and June 2012 were retrospectively analysed from a prospectively collected database. The patients were divided into SNB negative, INN, isolated tumour cells (ITC) and SNB positive groups. Outcome measures of nodal recurrence, distal recurrence and survival were used to assess the differences between the groups. RESULTS: 203 patients were SNB negative, 103 were positive of which 13 had ITC, 47 had INN (13%). Overall median follow up was 2.3 years (range 0.1–14.1 years). Our data demonstrated a statistically significant survival benefit for patients who had an INN compared to the SNB positive and ITC group. INN patients also had significantly better nodal and regional recurrence compared to SNB positive patients. There was no difference between INN and SNB negative patients. CONCLUSION: We have clinically demonstrated that patients with INN on SNB can be adequately treated as SNB negative patients