A teratoma (or dermoid cyst in the USA) is an uncommon and unusual form of cancer that occurs in the ovaries or testes. As the ovaries are the source of eggs and the testes are the source of sperm, both of which are used for fertilisation and growth into new humans, the cells (stem cells) in the ovary and testes when cancerous may develop into many different types of tissue. All types of strange tissue may develop in the tumour, including gland tissue, muscle tissue, skin and even teeth.
In women, symptoms are often minimal until the cancer is quite large, or bleeding occurs into it to cause an abdominal lump or pain. Men feel a hard tender lump in a testicle.
The tumour is diagnosed by x-rays, CT scans and biopsy of the tumour. Surgical removal of the cancer and surrounding tissue is usually all that is necessary, but rarely an aggressive cancer may be present that spreads to other parts of the body. The overall cure rate is close to 90%.