Neoadjuvant Checkpoint Inhibitor Therapy for Merkel Cell Carcinoma

A 78-year-old man presented with rapidly enlarging lymph nodes in the right preauricular region and neck. Needle biopsy revealed a cytokeratin 20-positive, high-grade neuroendocrine neoplasm consistent with Merkel cell carcinoma (MCC). Cross-sectional imaging disclosed a 5.2-cm intraparotid mass and extensive adenopathy in the ipsilateral cervical and submental chains (Figs 1A and 1C), without distant metastatic disease. A skin examination did not reveal a primary lesion (hence, stage IIIA, T0N1bM0). The patient's history was notable for hypertension, diet-controlled diabetes type II, high cholesterol, and a past history of numerous cutaneous basal and squamous cell carcinomas. He was quite active but reported discomfort from the bulk of the tumors. The patient was evaluated by the surgical oncology team, who believed that the parotid mass and cervical adenopathy were technically resectable but that resection carried a substantial risk of morbidity because of the potential need to sacrifice the facial and/or spinal accessory nerves and because of a likely margin-positive (R1 or R2) result. He was referred to the medical oncology team to discuss management options for regionally advanced, "borderline-resectable" MCC.