immature ovarian teratoma
Immature ovarian teratomas are uncommon ovarian germ cell tumors. They differ from mature ovarian teratomas (dermoid cysts) both histologically by the presence of immature tissue, and clinically by their more malignant behavior.
They are considerably less common than mature ovarian teratomas, representing less than 1% of ovarian teratomas . They also affect a younger age group, occurring most often in the first two decades of life (accounting for 10-20% malignant ovarian tumors in this age group).
Presentation may be with a palpable pelvic mass or less commonly with abdominal pain .
An immature cystic teratoma is characterized by the presence of immature or embryonic tissue, as well as the mature tissue elements seen in a mature teratoma. The proportion of immature neuroepithelium present correlates with the tumor grade (and hence prognosis) .
Macroscopically, immature teratomas are large, encapsulated masses which have a prominent solid component. As well as this, they may feature many of the components seen in a mature teratoma, such as hair, cartilage, bone and calcification.
- ipsilateral mature cystic teratoma: ~25%
- contralateral immature teratoma: ~10%
The imaging appearance is typical of a large, heterogeneous mass with a prominent solid component. However, the spectrum of appearances ranges from a predominantly cystic to a mostly solid mass. Immature teratomas tend to be larger than mature cystic teratomas at initial presentation.
Extension through the tumor capsule may be present.
Immature teratoma may metastasize to the peritoneum, liver or lung. Metastasis to the brain has also been reported .
Ultrasound appearance can be as a complex adnexal mass although is non-specific. Calcifications may be present.
The presence of a prominent solid component containing calcifications and small foci of fat is suggestive. Cystic components may contain serous, mucinous, or fatty sebaceous material. Hemorrhage may be present.
Treatment and prognosis
Treatment is generally with oophorectomy, and if distant metastases are present postoperative chemotherapy. Chemotherapeutic retro conversion is a phenomenon where the teratoma or its metastasis post radiotherapy become more histologically mature than the primary lesion.
Prognosis depends on the stage.
- peritoneal rupture
On imaging consider:
- mature ovarian teratoma
- tend to be smaller with more cystic change
- no evidence of metastases