Merkel cell carcinoma (MCC) is a malignant neuroendocrine tumor of the skin that demonstrates a remarkable tendency to metastasize. However, only a few cases of MCC brain metastases have been reported in the literature. We here present a unique case of a pituitary metastasis of MCC in a 65-year-old patient with a history of pituitary adenoma. This case is particularly novel due to the fact that the primary site of the MCC is unknown.