Merkel cell carcinoma of the eyelid: management and prognosis.

IMPORTANCE The literature on Merkel cell carcinoma (MCC) of the eyelid remains scarce, and there has yet to be a study using the most up-to-date TNM staging system for this rare but aggressive tumor. OBJECTIVE To analyze the TNM stage, management, and outcomes of patients with MCC of the eyelid. DESIGN, SETTING, AND PARTICIPANTS Retrospective case series of 21 patients from 5 tertiary referral centers in the United Kingdom and Australia with primary MCC of the eyelid presenting at a median age of 77 years, with median follow-up of 54 months. Tumors were staged according to the American Joint Committee on Cancer, 7th edition, TNM criteria for eyelid carcinoma and MCC. MAIN OUTCOMES AND MEASURES TNM stage, treatment modalities, and clinical outcome. RESULTS The eyelid carcinoma TNM stages were T2aN0M0 for 5 patients, T2bN0M0 for 7 patients, T3aN0M0 for 4 patients, T3bN0M0 for 3 patients, T2bN1M0 for 1 patient, and T3aN1M0 for 1 patient. The MCC TNM stages were T1N0M0 for 12 patients, T2N0M0 for 7 patients, T1N1M0 for 1 patient, and T2N1M0 for 1 patient. One patient had a sentinel lymph node biopsy, and 8 patients underwent head/neck imaging. Eighteen patients underwent a wide local excision, 12 with a paraffin section and 6 with a frozen section. Two patients underwent Mohs surgery, 1 of whom required an orbital exenteration. Twelve patients (57%) received adjuvant radiotherapy, and 2 patients received chemotherapy. The local recurrence rate was 10%, the regional nodal recurrence rate was 10%, and the distant metastatic recurrence rate was 19%. The lowest T category tumor metastasizing to both regional nodes and distant locations was a T2a (eyelid TNM)/T1 (Merkel TNM) tumor measuring 8 mm. Two patients with T3a (eyelid TNM)/T2 (Merkel TNM) tumors died of metastatic MCC. CONCLUSIONS AND RELEVANCE The majority of patients with MCC of the eyelid present with localized eyelid disease of T category T2 (eyelid TNM)/T1 (Merkel TNM). A wide local excision with margin control remains the mainstay of treatment, whereas the use of radiotherapy is institution specific. Tumors with a low T category are associated with regional nodal and distant metastatic disease. It may therefore be reasonable to consider a sentinel lymph node biopsy or strict regional lymph node surveillance for all MCCs of the eyelid, regardless of T category or size.