This paper reports a case of immature ovarian teratoma which is thought to be consistent with malignant neuroectodermal tumor of Aguiree, In addition, clinico-pathological findings of five other cases of immnauire ovarian teratoma were reviewed and compared with those of the present case. A 7-year and 8-month-old girl complained of lower abdominal pain and an ovarian tumor was suspected. She had high serum α-fetoprotein level (280ng/ml) and lactic dehydrogenase level (774 units). Laparotomy disclosed right ovarian tumor, measuring 11×9.5×6cm in size and weighing 380 g. It was well encapsulated except for small perforation. Cut surface revealed heterogenous, solid and cystic appearance with foci of hemorrhage and calcification. On detailed microscopical examination, majority of the tumor consisted of primitive neuroectodermal tissue. Undifferentiated cells showed slight to marked nuclear pleomorphism. Some foci showed marked resembrance to various types of neoplasm of nervous system, such as neuroblastoma, medulloblastoma, ependymoma, astrocytoma and oligodendroglioma. As poor prognosis was anticipated, she was treated with combination chemotherapy of cis-platin, vinblastine, bleomycin, endoxan and actinomycin-D. The patient demonstrated no clinical evidence of recurrence so far seven months after surgery. Five other cases of immature ovarian teratoma were studied histologically with particular reference to the amount of immature nervous tissue and their tumorous growth pattern. Although all the cases contained nervous tissue, the amount of immature element was much less than that of the present case. Only one case possessed few limited neuroblastomatous foci. All of them have been well without postoperative chemotherapy. Immature teratoma of the ovary in adult is generally believed to be malignant, while immature tissue elements in children are not considered to be malignant. The authors, however, believe that the case such as the present one has strong possibility of malignancy and should be treated with special care.
