Clinical characteristics and survival data of melanoma patients with nevus cell aggregates within sentinel lymph nodes.

Histopathologic differentiation of nevus cell aggregates and metastatic melanoma in lymph nodes is challenging. Patients with melanoma who had undergone sentinel lymph node (SLN) biopsy were evaluated using univariate and multivariate analyses as well as Kaplan-Meier statistics. Of the 651 patients, 50 (7.7%) had a nodal nevus in the SLN. In the logistic regression model, primary melanoma on the lower extremities proved to be the strongest independent negative predictor of nodal nevi with an odds ratio of 0.11 (95% confidence interval, 0.034-0.36; P = .0002). Overall 5-year survival (P = .17) and 5-year disease-free survival (P = .45) of patients with nodal nevi did not significantly differ from that of patients with negative SLNs. The frequency and anatomic localization of nodal nevi observed in the present study are in line with previous studies. Our 5-year survival data clearly demonstrate that nevus cell aggregates in lymph nodes have to be considered a benign condition even though it occurs in patients with melanoma. This study provides an indirect proof of validity and accuracy of current histopathologic methods for differentiation between nodal nevi and melanoma metastasis.