As a charity, we rely on voluntary contributions to provide this information. Germ cell tumours can appear at any age. Germ cell tumours come from egg or sperm producing cells. Sometimes instead of developing properly these cells remain in the wrong parts of the baby's body and can produce tumours. The tumours are sometimes given different names depending on where they develop e.g. yolk sac tumours, dysgerminomas and teratomas.
Malignant tumours have the ability to grow and spread to other parts of the body.
Benign tumours do not spread, but may cause problems by pressing on nearby tissue and body structures. The cause is unknown. The symptoms depend on where the tumour develops, but usually a lump appears that can either be felt or leads to other problems. Tests are likely to include a biopsy. A chest x-ray will be taken to see if there is a tumour in the lungs.