Objective: Lymphoscintigraphy for head and neck melanomas demonstrates a wide variation in lymphatic drainage pathways, and sentinel nodes (SNs) are reported in sites that are not clinically predicted (discordant). To assess the clinical relevance of these discordant node fields, the lymphoscintigrams of patients with head and neck melanomas were analyzed and correlated with the sites of metastatic nodal disease.
Methods: In 362 patients with head and neck melanomas who underwent lymphoscintigraphy, the locations of the SNs were compared with the locations of the primary tumors. The SNs were removed and examined in 136 patients and an elective or therapeutic regional lymph node dissection was performed in 40 patients.
Results: Lymphoscintigraphy identified a total of 918 SNs (mean 2.5 per patient). One or more SNs was located in a discordant site in 114 patients (31.5%). Lymph node metastases developed in 16 patients with nonoperated SNs, all underneath the tattoo spots on the skin used to mark the position of the SNs. In 14 patients SN biopsy revealed metastatic melanoma. After a negative SN biopsy procedure 11 patients developed regional lymph node metastases during follow-up. Elective and therapeutic neck dissections demonstrated 10 patients with nodal metastases, all located in predicted node fields. Of the 51 patients with involved lymph nodes, 7 had positive nodes in discordant sites (13.7%).
Conclusions: Metastases from head and neck melanomas can occur in any SN demonstrated by lymphoscintigraphy. SNs in discordant as well as predicted node fields should be removed and examined to optimize the accuracy of staging.