A spleen was a biological component found within various lifeforms, such as Humans and also dianogas.
Spleen-rot was a condition that could affect spleens, and they were also susceptible to rupture. The spleens of dianogas were used in the creation of Dianogan tea.
In the time of the Yuuzhan Vong War, the Jedi named Anakin Solo sustained a severe injury when his spleen burst. The resulting internal bleeding from this organ's damage ultimately resulted in his death.