Clinical features and prognosis of Asian patients with acral lentiginous melanoma who have nodal nevi in their sentinel lymph node biopsy specimen

Background: Nodal melanocytic nevi (NNs) encountered during sentinel lymph node biopsy (SLB) for malignant melanoma are usually difficult to distinguish from metastatic melanoma. However, NNs have not been well studied in acral lentiginous melanoma (ALM) in Asian populations. Objective: To investigate the clinical characteristics and significance of NNs in SLB specimens from patients with ALM. Methods: We retrospectively analyzed 84 patients with ALM who underwent SLB between June 2010 and July 2017. Results: Of the 84 patients with ALM, 9 (10.7%) had NNs in their SLB specimens. NNs were significantly more common in SLB specimens than in specimens not obtained by SLB. The presence of pre-existing melanocytic lesions was found to be associated with NNs (P<.001). The 5-year overall survival was significantly higher in patients with ALM with NNs than in patients with a positive SLB result (P=.047). Distant recurrence in patients with ALM with NNs was significantly lower than in patients a positive SLB result (P=.03). Limitations: The small sample size, single-center study design, and retrospective nature of the study were the limitations. Conclusion: In Asian populations, the prevalence of NNs in ALM is similar to that reported in Europe and the United States. The rates of distant recurrence and overall survival in patients with ALM who have NNs are similar to those of patients who do not have metastatic melanoma.