Purpose Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine cutaneous malignancy. Current recommendations include offering regional lymph node evaluation by either sentinel lymph node biopsy (SLNB) or complete lymph node dissection (CLND) to all patients with MCC; however, we hypothesized a cohort of low-risk patients may exist for whom regional nodal metastasis would be unlikely. Methods A retrospective review of the Department of Veterans Affairs national health care database was performed. Patients undergoing resection of primary MCC were identified; and demographic, medical, and social history; tumor characteristics; nodal status; and recurrence events were recorded. Results Between 1995 and 2006, 346 patients were diagnosed with MCC. Of these, 213 underwent resection of the primary lesion and evaluation of the draining lymph node basin. Fifty-four patients (25%) had tumors ≤ 1.0 cm in diameter. Average tumor diameter was 0.7 cm, and 63% were located on the head or neck. Only two patients (4%) with tumors ≤ 1.0 cm had regional lymph node metastasis, compared with 51 (24%) of 213 patients with tumors more than 1.0 cm (P < .0001). Both patients had clinically evident nodal disease at presentation and underwent CLND. Both have remained recurrence-free for 40 months. Thirteen (25%) of 51 patients with nodal metastasis and tumors more than 1 cm had occult nodal metastasis. Conclusion In this series, patients with MCC ≤ 1.0 cm were unlikely to have regional lymph node metastasis, suggesting that regional nodal evaluation may reasonably be avoided in these patients. However, these data support SLNB for MCC more than 1 cm in diameter.
Merkel cell carcinoma with lymph node metastasis in the absence of a primary site: Case report and literature review
