A tumor was a type of abnormal growth of tissue, often found in one's brain. Clone trooper CT-5385, also known as Tup, had a tumor on his brain as the result of the malfunction of the inhibitor chip. The medical droid that discovered the tumor in Tup's brain, AZ-3, saw the tumor as rare in the clone's kind.
- Star Wars: The Clone Wars – "Conspiracy" (First appearance)
- Star Wars: The Clone Wars – "Fugitive"
- Alphabet Squadron (Mentioned only)
- Aftermath: Empire's End (Mentioned only)