A carotid body tumor is a rare, slow-growing mass that sits at the fork of the carotid artery in the neck. It starts silent, but as it enlarges it pushes on nearby nerves and vessels, sending clear signals. Neck lump is the star. You feel a painless, rubbery mass just below the jaw that moves up when you swallow but not side to side. Pulsing sensation follows. The lump throbs in rhythm with your heartbeat, especially when you lie flat. Hoarseness or voice change appears if the tumor presses on the nerve to the voice box. Swallowing can catch. Food... Learn more