16.9.4Ovarian Mixed-Cell Malignant Germ Cell Tumor

•Frequency 11%

•Occurrence often in precocious puberty

•AFP/b-HCG levels often high

•Therapy: after resection, chemotherapy

•Rare disorder

•Occurrence in dysgenic gonads

•Polyembryoma, choriocarcinoma with early metastases

16.10Extragonadal Germ Cell Tumors Subtypes

•Midline tumor

•Aberrant location of embryonal germ cells (see Pathogenesis)

•Main sites of involvement: sacrococcygeal, mediastinal, intracranial, retroperitoneal

•Majority of malignant teratomas have favorable prognosis after total resection alone in stage I and after combined radioand chemotherapy in stage II or III disease

In the following sections, the particular tumors are described.

16.10.1 Sacrococcygeal Teratoma

•Sixty-eight percent of all extragonadal tumors

•Newborns: 1:40,000

•Ratio of male to female is 1:3

•Occasionally detectable by ultrasound during pregnancy

•Sometimes connected with other congenital anomalies

•In about 17%, malignant components (high levels of AFP and b-HCG, mostly as embryonal carcinoma) can be present

•Early complete resection important, including removal of coccyx

•Cure rate 95%

•Malignant form: after resection, chemotherapy used

16.10.2 Intracranial Teratoma

•In the area of the pineal gland or suprasellar region, or combined

•Symptoms: visual disturbances, diabetes insipidus, hypopituitarism, anorexia, precocious puberty

•AFP and b-HCG levels often high

•Histology: predominantly germinoma, otherwise mixed form, choriocarcinoma or teratocarcinoma

•Sometimes intracranial spread, drop metastases

•Management: biopsy, chemotherapy, eventually radiotherapy (see above)

16.10.3 Mediastinal Teratoma

•Anterior mediastinum involved

•Mean age 3 years

•Symptoms: dyspnea, wheezing, thoracic pain, superior vena cava syndrome

•Majority are benign dermoid cysts; sometimes with calcium deposits visible on X-ray

•Differential diagnosis: thymoma, lymphoma, bronchogenic cyst, lipoma, intrathoracic thyroid tissue

•Management: surgery, chemotherapy

•Prognosis: 4 years overall survival 71%, four event-free survival 69% (POG data). If a malignant component is present, unfavorable prognosis despite combined chemoand radiotherapy (30–50% of patients have initial metastases of lung, bone, and/or bone marrow)