An unusual lump on your testicles, abdomen, or tailbone may be a sign of extracranial germ cell tumors. In girls (usually 15 years or older), no lump may present itself, but you may feel a range of other symptoms, including abdominal pain, constipation, or fever. You may also stop menstruating regularly or bleed at unusual times. Other diseases and conditions may cause lumps and other symptoms. It is important to visit your doctor immediately if you see a lump; other symptoms require a visit only if they persist or worsen.