Learn all about Germinoma (germ cell tumors). A germinoma is a type of germ cell tumor that is most often found in the brain. Typically, germ cells migrate to the reproductive organs (female ovaries or male testes) during fetal development. However, if these germ cells don’t migrate to the correct location, they can become trapped in the brain and multiply in areas where they shouldn’t.
The term Germinoma 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 germinoma 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 germinomatous tumors.
Germ cell tumors, especially germinomas, can disseminate the neuroaxis at the time of diagnosis or early in the course of illness. There is no specific staging system which has been uniformly accepted for germ cell tumors, and most investigators utilize the TM system employed for medulloblastomas.
The cause of germ cell tumors isn’t completely understood. A number of inherited defects have also been associated with an increased risk for developing germ cell tumors including the central nervous system and genitourinary tract malformations and major malformations of the lower spine. Specifically, males with cryptorchidism (failure of the testes to descend into the scrotal sac) have an increased risk to develop testicular germ cell tumors. Cryptorchidism can occur alone, however, and is also present in some genetic syndromes.
Germinoma carry a relatively excellent prognosis. It’s very unlikely that the tumor will spread outside the central nervous system. Overall, germinomas are cured in more than 90 percent of cases. Most patients with germ cell cancer will need to be treated with combination chemotherapy for at least 3 cycles. The chemotherapy regimen most commonly used in germ cell tumors is called PEB (or BEP), and consists of bleomycin, etoposide, a platinum-based antineoplastic (cisplatin).
Germinoma (Germ Cell Tumors)
A germinoma is a type of germ cell tumor, which is not differentiated upon examination. It may be benign or malignant. Germ cell tumors arise in the ovaries (in girls), the testes (in boys), and in several other locations, including the lower back (common in infancy), the abdomen, the chest, and within the brain. Germ cell tumors starting within the brain are discussed further under Brain Tumors. Germ cell tumors in the testes of an adolescent male commonly present as an enlarging, solid mass, which may be painful. Within the ovaries, germ cell tumors can usually be distinguished from ovarian cysts, which are much more common, using ultrasound. Germ cell tumors can spread to lymph nodes, lung, liver, and brain. Some germ cell tumors secrete hormones that can lead to changes resembling puberty. Germ cell tumors are more common, but still rare, in undescended testes that were not corrected. Abnormal ovaries or testes due to genetic syndromes (such as Turner’s or Klinefelter’s) are also at higher risk.
Symptoms of germ cell brain tumors typically depend on where they have developed in the brain. For tumors in the pineal gland region following symptoms can occur:
- Hydrocephalus (swelling of the brain)
- Behavioral or cognitive changes
- Uncoordinated body movement (ataxia)
- Vision changes, including double vision and difficulty looking up
- Diabetes insipidus (an uncommon disorder characterized by intense thirst and the passing of large amounts of urine)
- Delayed puberty
- Early (precocious) puberty
- Stunted growth
- Vision changes including loss of peripheral vision or decrease in vision.
- Elevated levels of alpha-fetoprotein (AFP)
- Elevated levels of beta-human chorionic gonadotropin (ß-HCG)
- Constipation, incontinence, and leg weakness can occur if the tumor is in the sacrum (a segment of the vertebral column that forms the top part of the pelvis) compressing structures
- Abdominal pain
- Shortness of breath or wheezing if tumors in the chest are pressing on the lungs
Germinoma treatment may include:
- Chemotherapy; Chemo may be injected into the bloodstream, so that it can travel throughout the body. Some chemo may be given by mouth. Combination therapy uses more than one type of chemo at a time.
- Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or stop them from growing (dividing) and making more cancer cells. External radiation uses machines outside the body to deliver the X-ray dose.
- Bone marrow transplantation
- Supportive care (for the effects of treatment)
- Hormonal replacement (if necessary)
- Antibiotics (to prevent or treat infections)
- Continuous follow-up care (to determine response to treatment, detect recurrent disease, and manage the late effects of treatment)
- Surgery: While biopsies can be done to diagnose germinomas, resection (surgical removal) is generally not needed since most germinomas respond well to chemotherapy and radiation.
The prognosis for germ cell tumors, independent of their location in the CNS, is highly dependent on the histological subtype of the tumor present. In reported series of patients treated for germ cell tumors, it is often difficult to determine the relative prognosis of a specific type of tumor, given the variability of treatment, even at one institution. In general, germinomas carry an excellent prognosis, with most series suggesting five-year progression-free survival rates and cure in well over 90% of patients.