Background: Since the advent of sentinel lymph node (SLN) biopsy, patients with cutaneous melanoma have been referred to surgeons for consideration for SLN biopsy, sometimes even after the wide local excision (WLE) of the primary melanoma has been performed. This has raised the question of the reliability and validity of a lymphoscintigram performed for lymphatic mapping of the SLN after there has been anatomic rearrangement of the skin following the WLE of this primary melanoma.
Methods: We conducted a prospective study of 20 consecutive patients with cutaneous melanomas with thickness less than 1.00 mm, who volunteered to undergo preoperative and postoperative lymphatic mapping to determine if there were any changes in the lymph nodes that were identified following the WLE of the primary melanoma. Each of the patients had a resection with a minimum of 1.0 cm margin, and closure of their wounds with either transposition flap or double advancement flaps.
Results: Lymphatic mapping was clearly identified in all 20 patients. One patient declined to undergo postoperative lymphatic mapping. Postoperative lymphatic mapping performed in the remaining 19 patients 2-4 weeks following WLE was identical to the preoperative mapping in 13 patients (68%), showed additional lymph nodes in 4-5 patients (21-26%), and showed fewer lymph nodes in 1-2 patients (5-10%).
Conclusions: Lymphatic mapping performed after a WLE of a primary cutaneous melanoma should be as reliable in identifying the SLN as a preoperative lymphatic mapping in 90% of the patients.