An 8 cm teratoma is not considered large. Teratoma is a common type of germ cell tumor and is associated with abnormal differentiation of germ cells during the embryonic period. Teratomas can occur in several organs of the body, such as the stomach and intestines, testes, ovaries, and brain. Teratomas include mature teratomas and immature teratomas. Mature teratomas contain a variety of components, including teeth, bones, hair, skin, and nerve tissue, while malignant teratomas are poorly differentiated and have no or little formed tissue. Teratomas are mostly asymptomatic in early stages and clinically difficult to detect early, therefore teratomas can grow very large, and teratomas of more than 10 cm are relatively common in clinical practice.