The EORTC protocol for sentinel lymph node biopsy (SLNB) reveals a high number of nodal nevi and a strong association with nevus-associated melanoma

Abstract

BackgroundThe diagnosis of nodal nevi (NN) is challenging as they mimic melanoma metastases (MM), with a detection rate mostly ranging between 1% and 11% in sentinel lymph node biopsy (SLNB). Herein, we assessed the incidence of NN and the association with the clinical-pathological features of primary melanoma, adopting the updated European Organisation for Research and Treatment of Cancer (EORTC) protocol for SLNB. MethodsAll cases of paired melanoma and SLNB were retrospectively evaluated (April 2019-May 2020). Appropriate statistical tests were adopted, with significant variables included in the logistic regression model. Results81 patients and a total of 186 lymph nodes (LNs) were included. Eleven patients had only NN and 4 had both NN and MM (18.5%); 29 LNs (15.6%) showed at least one NN and 12 (6.5%) showed more than one NN (a total amount of 43 NN was detected). All NN and none MM stained for p16. NN were associated with age < 60 years (p: 0.042), no ulceration (p: 0.025) and nevus-associated melanoma (NAM) (p: 0.018), with this latter being the only predictor at the logistic regression model (p: 0.022). ConclusionsThe updated EORTC protocol shows a high number of NN and highlights a strong association with NAM.