Mucoepidermoid Carcinoma—Unknown Primary and Late Distant Metastasis: An Unusual Course of the Disease

The authors report the case to understand this unusual presentation and prognosis of mucoepidermoid carcinoma following treatment. We present a case of mucoepidermoid carcinoma in a 67-year-old man. The cancer was diagnosed in the right side of his neck but the primary tumor remained unknown despite attempts at staging. The neck was treated successfully and followed up for 2 years. Metastasis of the primary lesion to the left triceps was diagnosed following a swelling noticed by the patient during the 2-year follow up period. Mucoepidermoid carcinoma can be a low, intermediate or high-grade malignancy and can metastasize to different parts of the body. However, this is the first case report of a metastasis to the triceps muscle.