Metastasis has been noted in about 22% of cases at time of diagnosis. Males are roughly twice as commonly affected in developing<unk> s. They are most commonly diagnosed between the ages of 10 and 21. Often, serum and spinal fluid tumor markers of alpha-fetoprotein and beta-HCG are tested. Pure<unk> s are not associated with these markers. Nongerminomatous germ-cell tumors may be associated with increased markers such as alpha-fetoprotein with yolk sac tumors, as well as embryonic cell carcinomas and immature teratomas and beta-HCG, which occur in choriocarcinomas. In one to 15% of<unk> s, a low level of beta-HCG may be produced. Although controversial, HCG-secreting<unk> s may be more aggressive than nonsecreting ones. Classification The term<unk> " most often refers to a tumor in the brain that has a histology identical to two other tumors, dysgerminoma in the ovary and seminoma in the testis. Since 1994, MeSH has defined<unk>  as "a malignant neoplasm of the germinal tissue of the gonads, mediastinum, or pineal region" and within its scope included both dysgerminoma and seminoma. Collectively, these are the seminomatous or<unk> tous tumors. Locations Ovary (dysgerminoma) and testis (seminoma) Dysgerminoma is the most common type of malignant germ-cell ovarian cancer. Dysgerminoma usually occurs in adolescence and early adult life; about 5% occur in prepubertal children. Dysgerminoma is extremely rare after age 50. It occurs in both ovaries in 10% of patients and, in a further 10%, a microscopic tumor is in the other ovary. A 7.4 x 5.5-cm seminoma in a radical orchiectomy specimen from a 27-year-old man Seminoma is the second-most common testicular cancer; the most common is mixed, which may contain seminoma. Abnormal gonads (due to gonadal dysgenesis and androgen insensitivity syndrome) have a high risk of developing a dysgerminoma. Most dysgerminomas are associated with elevated serum lactic dehydrogenase, which is sometimes used as a tumor marker. Metastases are most often present in the lymph nodes. Intracranial<unk>  Intracranial<unk>  occurs in 0.7 per million children. As with other germ-cell tumors (GCTs) occurring outside the gonads, the most common location of intracranial<unk>  is on or near the midline, often in the pineal or suprasellar areas; in 5-10% of patients with<unk>  in either area, the tumor is in both areas. Like other GCTs,<unk> s can occur in other parts of the brain. Within the brain, this tumor is most common in the hypothalamic or hypophyseal regions. In the thalamus and basal ganglia,<unk>  is the most common GCT. The diagnosis of an intracranial<unk>  usually is based on biopsy, as the features on neuroimaging appear similar to other tumors. Cytology of the cerebrospinal fluid often is studied to detect metastasis into the spine. This is important for staging and radiotherapy planning. Intracranial<unk> s have a reported 90% survival to five years after diagnosis. Near total resection does not seem to influence the cure rate, so gross total resection is not necessary and can increase the risk of complications from surgery. The best results have been reported from craniospinal radiation with local tumor boost of greater than 4,000 centigray (cGy).
Germinoma
Mantleoma
Central neurocytoma
Neurothekeoma
Sialoblastoma
Medulloblastoma
Pinealoma
Chordoma