A thyroid cyst is a fluid-filled sac sitting inside the thyroid gland. Most are harmless water balloons, so symptoms are usually mild and show up only when the cyst gets big.

Neck lump is the star. You notice a smooth, round bump at the base of your throat that bobs up when you swallow.

Size can change. The lump may swell after a cold or shrink on its own, making it seem to “come and go.”

Pressure or fullness is common. You feel like something is stuck in your throat, especially when looking up or wearing a tight collar.

Hoarseness creeps in if the cyst presses on the nerve to the voice box. Your voice sounds raspy or deeper.

Pain is rare but can shoot into the ear or jaw if the cyst bleeds or grows fast.

Late signs include a hard, fixed mass, rapid heartbeat, or weight loss—an alarm that the cyst may be cancerous.