A 60-year-old woman noticed an enlarging "bump" beneath her tongue for the past year. She does not smoke or use alcohol. On physical examination, there is a 2.5-cm, movable, submucosal mass arising in the minor salivary glands on the buccal mucosa beneath the tongue on the right. Histologic examination of the excised mass shows that it is malignant and locally invasive. The tumor recurs within 1 year. Which of the following is the most likely diagnosis?

Mucoepidermoid carcinomas can arise in major and minor salivary glands. They account for most neoplasms that arise within minor salivary glands, particularly malignant neoplasms. Low-grade mucoepidermoid carcinomas may be invasive, but the prognosis is usually good, with a 5-year survival of 90%. High-grade mucoepidermoid carcinomas can metastasize and have a 5-year survival of only 50%. Non- Hodgkin lymphomas are found in adjacent cervical lymph nodes or in the Waldeyer ring of lymphoid tissue. A primitive neuroectodermal tumor, also known as an olfactory neuroblastoma, is a small, round, blue cell tumor of childhood; it is likely to arise in the nasopharyngeal region. Pleomorphic adenomas are more common in the major salivary glands than are mucoepidermoid tumors, and they are more likely to be indolent. Squamous cell carcinomas are invasive and arise in the buccal mucosa. Warthin tumors are uncommon and indolent.