Lymphatic drainage patterns of head and neck cutaneous melanoma observed on lymphoscintigraphy and sentinel lymph node biopsy

BACKGROUND: The purpose of this study was to evaluate lymphatic drainage patterns of head and neck cutaneous melanoma observed on preoperative lymphoscintigraphy and sentinel lymph node biopsy (SLNB) and determine discordancy from clinically predicted lymphatic drainage patterns. METHODS: We conducted a retrospective chart review of 114 patients with head and neck cutaneous melanomas evaluated with preoperative lymphoscintigraphy and SLNB from January 2001 through July 2004. RESULTS: At least one sentinel lymph node (SLN) was identified in 97% of cases. On preoperative lymphoscintigraphy, an SLN was identified in an area not clinically predicted in 49 cases (43%). The most common sites of discordancy were in areas not typically dissected in standard neck dissections, such as the postauricular region, or in areas of more distant drainage than described previously, such as the inferior or posterior neck. Their percentages of discordant cases were 51%, 27%, and 22%, respectively. The sites of regional recurrence occurred in two cases not predicted on preoperative lymphoscintigraphy and in two cases of failed SLNB. CONCLUSIONS: On the basis of preoperative lymphoscintigraphy and the results of SLNB, head and neck cutaneous melanomas do have expected lymphatic drainage patterns despite perceived discordancy with previously clinically predicted drainage patterns that are based on standard neck dissection specimens. These "discordant" sites can still harbor melanoma, and all sites predicted on preoperative lymphoscintigraphy still need to be explored. The four cases of recurrences underscore the importance of close follow-up for all patients regardless of the SLNB result.