A 25-year-old woman is concerned about a lump on the left side of her neck that has remained the same size for the past year. Physical examination shows a painless, movable, 3-cm nodule beneath the skin of the left lateral neck just above the level of the thyroid cartilage. There are no other remarkable findings. Fine-needle aspiration of the mass is performed. Her physician is less than impressed by the pathology report, which notes, "Granular and keratinaceous cellular debris". Fortunately, she has saved her Robbins pathology textbook from medical school. She consults the head and neck chapter to arrive at a diagnosis, using the data from the report. Which of the following terms best describes this nodule?

Branchial cysts, also known as lymphoepithelial cysts, may be remnants of an embryonic branchial arch or a salivary gland inclusion in a cervical lymph node. They are distinguished from thyroglossal duct cysts by their lateral location, the absence of thyroid tissue, and their abundant lymphoid tissue. Occult thyroid carcinoma, often a papillary carcinoma, may manifest as a metastasis to a node in the neck, but the microscopic pattern is that of a carcinoma. About 5% of squamous cell carcinomas of the head and neck initially manifest as a nodal metastasis, without an obvious primary site. This patient is quite young for such an event, however. Mucoceles form in minor salivary glands; mucoepidermoid tumors form in salivary glands. The nodule in this patient is in the neck. Paragangliomas are solid tumors that may arise deep in the region of the carotid body near the common carotid bifurcation.