About 50% of pure immature teratomas of the ovary occur between the ages of 10 and 20 years, and they rarely are seen in postmenopausal women. Immature teratomas are classified according to a
grading system (grades 1 to 3) that is based on the degree of differentiation and the quantity of immature tissue.Treatment for immature teratoma includes both surgery and chemotherapy, in most cases.
Grade 1 tumours have an excellent prognosis, and no adjuvant therapy is required.