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?