Version July 2025
| I. Benign teratomas |
| Mature teratoma |
| Grade 0 - All component tissues appear well differentiated |
| Grade 1 - Occasional microscopic foci contain incompletely differentiated tissues, not exceeding 10 percent of the sampled surface |
| Immature teratoma, benign |
| Grade 2 - Immature tissues make up between 10 and 50 percent of the sampled tumor surface |
| Grade 3 - Over half of the surface examined is composed of undifferentiated tissues of uncertain metastatic potential; a benign course is still possible |
| II. Malignant teratomas |
| With areas of germ cell tumor |
| Germinoma (seminoma, dysgerminoma) |
| Embryonal carcinoma |
| Choriocarcinoma |
| Yolk sac tumor |
| Mixed (any combination of the above) |
| With nongerminal malignant tumor pattern |
| Carcinoma |
| Sarcoma |
| Malignant embryonal tumor |
| Mixed |
| Immature teratoma, malignant |
| A teratoma that would otherwise be classified as benign immature teratoma, but which subsequently became metastatic |
