Intraoperative lymphatic mapping and sentinel lymph node biopsy for Merkelcell carcinoma

Background: Merkel cell carcinoma is a rare cutaneous neoplasm which common ly spreads to the regional lymph nodes. The feasibility of identifying the sentinel node in patients with clinically node-negative Merkel cell carcino ma was evaluated. Methods: Sentinel lymphatic mapping was performed in 18 patients with stage 1 Merkel cell carcinoma using the combination of isosulphan blue dye and T c-99m-radiolabelled sulphur colloid. Patients with tumour metastasis in the sentinel node underwent complete dissection of the remainder of the lymph node basin. Results: Eighteen patients underwent removal of 35 sentinel nodes. Two pati ents demonstrated metastatic disease in the sentinel lymph nodes; complete dissection of the involved nodal basin revealed no additional positive node s suggesting that the sentinel lymph node had been identified. The node-neg ative patients received no further surgical therapy, with no evidence of re current disease in the sentinel nodal basin at a median of 7 months' follow -up. Conclusion: Sentinel node biopsy is feasible in patients with Merkel cell c arcinoma. It call be used to stage patients and provides important prognost ic information. In those with subclinical nodal disease, it may direct earl y regional lymphadenectomy but the effect of such surgery on survival remai ns unclear.