Is there a sickness where your insides are growing but your outside stop growing?

Yes, a condition known as "acromegaly" can cause the body to grow abnormally due to excess growth hormone, primarily affecting bones and soft tissues. However, it typically doesn't lead to a situation where the inside grows while the outside does not, as both are generally affected. There are also other conditions, such as certain tumors or hormonal imbalances, that can lead to unusual growth patterns, but they don't precisely match your description. If you are referring to a specific syndrome, please provide more details for clarification.