E32: Diseases of thymus

E32.9: Disease of thymus, unspecified

The thymus gland is a small organ which forms part of the immune system. The thymus gland lies below the neck and is partly surrounded by the lungs. Immune cells mature in the thymus gland. The thymus gland is at its largest in children and adolescents. Later in life, the thymus gland gradually shrinks since it is no longer required.