Germ cell tumors can show up in the testicles, ovaries, or along the midline of the body. The first thing people usually notice is a painless lump or swelling. In the testicle it feels like a firm, heavy ball that does not go away. In the ovary it can cause bloating or a tight waistband even when weight has not changed.

If the tumor makes hormones, the body may shift quickly. Boys can grow breast tissue or feel tender nipples. Girls may skip periods or start unexpected vaginal bleeding. Some people notice deeper voice or facial hair that was not there before.

When the tumor grows near the brain—especially in the pineal or pituitary region—morning headaches and vomiting that gets better after breakfast are common. Eyes may look upward without trying, or focus may blur. Kids can wet the bed again or drink water non-stop.

Chest tumors can press on breathing tubes and cause a dry cough that no cold explains. Sometimes face and arm swelling appears because blood flow is blocked.

Back pain that wakes a teenager at night, or leg weakness that makes stairs hard, can mean the tumor is sitting near the spine.