It turns out our pediatrician's best guess of a birth defect was right on the money.
Grace visited the ENT today, and he feels that the lump in her neck is something called a thyroglossal duct cyst. A thyroglossal duct cyst is a neck mass or lump that develops from cells and tissues remaining after the formation of the thyroid gland during embryonic development. This type of cyst is a congenital (present from birth) defect. When the thyroid gland forms during embryonic development, it begins at the base of the tongue and moves down the neck through a canal called the thyroglossal duct. This duct normally disappears once the thyroid reaches its final position in the neck. Sometimes, portions of the duct remain leaving cavities or pockets called cysts. This is the ENT's first guess.
Outside of that there is another possibility, which is that of a dermoid cyst. A dermoid cyst is a pocket or cavity under the skin that contains tissues normally present in the outer layers of the skin. The pocket forms a mass that is sometimes visible at birth or in early infancy but often is not seen until later years. Dermoid cysts are usually found on the head or neck, and sometimes on the face. (My close friends and family may remember that I had a cyst like this except it was on my ovary and had to be removed when I was in my mid-twenties.) A dermoid is also congenital.
Either of these two cysts require surgery since it is likely the cyst will keep growing and growing. If it turns out to be a thyroglossal duct cyst, the surgery performed will be the Sistrunk procedure, which removes part of the hyoid bone (which holds the base of the tongue up inside your throat) along with the entire duct and cyst. According to Dr. M, she won't "miss" the bone. If it turns out to be a dermoid cyst, he said the surgery is actually much less involved and simpler.
Dr. M informed us that he really won't know exactly what the cyst is until he removes it, and it is sent to pathology. Grace will have an ultrasound on her neck tomorrow after school, and then depending on the result of that ultrasound, her surgery will be scheduled.
So now that I've gotten to the medical definition of all of this, how does this make Gracie feel?
During the appointment, Dr. M immediately noticed that Grace appeared afraid as he was describing what would need to happen. Her lip was quivering, and she had two of her fingers in her mouth. This immediately made me tear up a bit, and I put Grace on my lap to cuddle her a bit. I quickly suppressed that feeling. Charlie and I exchanged a quick look at each other to communicate our unified feeling of "oh crap." We were hoping this wouldn't come to surgery as Gracie has never been put under before. It was a relief to see the ENT pay close attention to Grace, though. To me that was a sign of his compassion for children. God bless children's doctors.
Grace is already asking us questions, and isn't too pleased with needing to sleep overnight in a hospital. We, of course, told her that she wouldn't be alone. She liked the idea of bringing her favorite blanket, pillow, and her cuddly Danni kitty.
Tomorrow's ultrasound will determine the size and scope of the issue in Grace's neck. It will also determine if Grace' thyroid is in the correct location in her neck.
Surgery will be scheduled after the results of the ultrasound and when Dr. M can fit his schedule together with one of his partners for the surgery. We are still in a watch and wait situation, but we know more now. The good news is that she is safe for now, and these cysts are almost always benign. Thank goodness for that. :)
I'll update here as we find out more. Thanks in advance for your good thoughts and prayers.