An 18-year-old woman went to her physician because she had noticed a swelling in the midline of her neck. She said she had first noticed this swelling 3 years previously, and it had gradually increased in size. On physical examination, a small swelling was found in the midline of the neck; it measured about 0.5 inch (1.25 cm) in diameter. It was situated just below the body of the hyoid bone, was soft and fluctuant, and moved upward on swallowing. Nothing else abnormal was discovered. The physician made the diagnosis of thyroglossal cyst based on the following symptoms and signs except which?