You could try and argue that the TSA website allows "...items used to augment the body for medical or cosmetic reasons such as mastectomy products, prosthetic breasts, bras or shells containing gels, saline solution, or other liquids...", but I think you would be taking a risk. The screeners could argue that the allowance for those items falls in under the heading " Travelers with Disabilities and Medical Conditions" and the traveler, in this case, doesn't have the disability or medical condition that requires the otherwise prohibited item.