NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,800 terms related to cancer and medicine.
Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.
- listen (SEH-mih-NOH-muh)
- A type of cancer that begins in cells that make sperm or eggs. Seminomas occur most often in the testicles or the ovaries. They may also occur in other organs, such as the brain, chest, or abdomen. This happens when cells that have the ability to form sperm or eggs are found in other parts of the body. Seminomas grow and spread slowly.