Polymorphous low-grade adenocarcinoma (PLGA) is a malignant neoplasm of low aggressiveness that occurs almost exclusively in the minor salivary glands, primarily those in the palate. We report a case of PLGA that arose in the base of the tongue and subsequently metastasized to the neck. The tumor was resected through the oral cavity with wide margins and dissection. The neck metastasis was treated with radical neck dissection and radiotherapy. The patient recovered and remained disease-free at follow-up 30 months later. This case shows that PLGA, which has a variable morphologic appearance, can occur at sites other than the salivary glands.