PEDT-3

Background: Germ cell tumors (GCTs) containing a teratoma component is a group of diseases consisting of various pathological conditions such as mature teratoma, immature teratoma, teratoma with malignant transformation, and mixed tumor with other GCTs. There is controversy about the efficacy and safety of radiation and chemotherapy for GCTs with teratoma component other than mature teratomas. Methods: Of 212 cases of GCTs treated at Tohoku University Hospital Neurosurgery from January 1990 to March 2021. In this study, 23 histologically verified GCTs containing teratoma components were included. Pathological findings, recurrence, survival, and late complications were examined. Results: The age of onset was 2 months-21 years (median 10.5 years). Histological diagnosis was mature teratoma alone in 5 cases, mixed GCTs with mature teratoma in 11 cases, immature teratoma in 5 cases, and mixed tumor with mature teratoma and germinoma in 2 cases. Patients except mature teratoma were treated by chemotherapy alone or radiochemotherapy. During follow-up for 7–362 months (median 135 months), 3 patients relapsed. One of these patients was diagnosed with mature teratoma at the time of treatment and did not receive post-treatment, but relapsed as germinoma 21 years later. A review of pathological specimens at the time of initial onset revealed immature teratomas in addition to mature teratomas. Recurrent lesions in 3 cases were controlled by additional treatment, and no deaths due to tumor progression were observed. On the other hand, of the 18 patients who underwent radiochemotherapy, 1 developed primary hypothyroidism and 2 developed thyroid cancer and leukemia. Conclusion: GCTs with teratoma component often contain malignant histological types and require caution when making a pathological diagnosis. In these cases, tumor control can be expected by radiation or chemotherapy, but there is a risk of developing endocrine disorders and secondary tumors, and further studies are needed to optimize treatment.