Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine cutaneous malignancy that comprises less than 1% of skin cancers [1,2]. MCC most commonly presents as a skin lesion on sun-exposed areas of the body, affecting head and neck subsites in 53% of cases [1]. The average age at diagnosis is 69 years old, and white males are most frequently affected due to fair complexion [1].

MCC is twice as deadly as cutaneous melanoma, with a three-year mortality rate of 33% [3,4]. The incidence of MCC is growing worldwide, with the highest rates found in Queensland, Australia [5]. In the United States between 2000‐2013, the incidence nearly doubled, and the rate is expected to reach 3,284 cases per year by 2025 [6,7].

Thirty percent of patients with MCC present with both regional and distant metastases at the time of diagnosis. MCC metastases to the thyroid gland in general are uncommon—it is hypothesized the organ’s high oxygen saturation and iodine content foster unfavorable growth conditions for malignant cells which have relatively anaerobic metabolism [1,8]. There have been only five reported cases in the literature, with the earliest case reported in 2010. We present a sixth case from our institution, as well as a review of those cases previously published.