A 65-year-old woman has noticed a slowly enlarging nodule on her face for the past 3 years. On physical examination, a 3-cm, nontender, mobile, discrete mass is palpable on the left side of the face, anterior to the ear and just superior to the mandible. The mass is completely excised, and histologic examination shows ductal epithelial cells in a myxoid stroma containing islands of chondroid like tissue and bone. This patient is most likely to have which of the following neoplasms?

Pleomorphic adenoma is the most common tumor of the parotid gland. These tumors are rarely malignant, although they can be locally invasive. An acinic cell tumor is composed of cells resembling the serous cells of the salivary gland; they are generally small, but about one sixth metastasize to regional lymph nodes. Mucoepidermoid tumors are less common than pleomorphic adenomas in major salivary glands. They may be high-grade and aggressive. Primitive neuroectodermal tumor, also known as an olfactory neuroblastoma, is a small, round, blue cell tumor that occurs in childhood. It is likely to arise in the nasopharyngeal region. Squamous cell carcinomas arise in the buccal mucosa and are invasive. Warthin tumors are uncommon and indolent, although they may be bilateral or multicentric.