Germ cells are primitive cells within the body that normally mature into ova (egg) or sperm cells. More than 90% of all germ cell tumors are gonadal; that is, they develop in the ovaries or the testes (the gonads). The remaining 5–10% of germ cell tumors arise outside of the gonads: these are the extragonadal germ cell tumors. These tumors occur mostly in the chest, lower back, and head.
The symptoms of an extragonadal germ cell tumor depend on the type and location of the tumor. Mediastinum Germ cell tumors of the mediastinum are primarily diagnosed in men between the ages of 20 and 30. Symptoms include: * chest pain * breathing problems * cough * fever Presacral Area Presacral germ cell tumors are primarily diagnosed in children under the age of six. These are generally seen as a mass in the lower abdomen or buttocks. Because of the size and location of the tumor, the patient may have difficulty passing urine or having a bowel movement. Tumors detected in children under the age of six months are benign in 98% of cases. Tumors detected in children over the age of six months are malignant in approximately 65% of cases. Pineal Area Almost all pineal germ cell tumors occur in people under the age of 40. Symptoms include: * headache * nausea * vomiting * lethargy * difficulty walking * memory loss * an inability to look upward * uncontrolled eye movement * double vision In some cases, a pineal germ cell tumor can begin to produce hormones that can cause a child to enter puberty at an abnormally young age (precocious puberty).
The cause, or causes, of extragonadal germ cell tumors are not known.
The diagnosis of an extragonadal germ cell tumor usually begins with a thorough physical examination. In cases where a presacral tumor is suspected, this will include a rectal examination and a pelvic examination in women. In cases where a germ cell tumor of the pineal area is suspected, a complete neurological examination will be performed. Mediastinum The first test for a tumor of the mediastinum is a standard chest x ray. This will detect the tumor and show its location in 95% of cases. This will be followed by a computed tomography (CT) scan of the chest to determine the size of the tumor and by a CT scan of the abdomen to see if there has been a spread (metastasis) to the liver or other abdominal sites. Diagnosis is generally confirmed by taking a needle biopsy of the tumor. In this procedure, a needle is injected directly into the tumor and a sample is removed. Certain types of nonseminomas can be detected via blood tests for levels of alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (beta-hCG). Presacral Area Germ cell tumors of the presacral area are diagnosed by either magnetic resonance imaging (MRI) or ultra-sound imaging techniques. These techniques allow for the determination of both the location and the precise size of the tumor. To check for metastases, a bone scan, chest x rays, and a CT scan of the lungs should be performed. Sometimes a bone marrow biopsy is also ordered. Diagnosis of a presacral germ cell tumor is confirmed by a direct biopsy of the tumor. This may be either an excisional biopsy, in which the tumor is first removed, then examined; or, a needle biopsy, in which only a sample of the tumor is removed for examination. Pineal Area A CT scan of the head will usually show a pineal tumor. An MRI scan, using gadolinium as a tracer chemical, may also be ordered. Blood tests for AFP and beta-hCG may help to diagnose pineal area germ cell tumors. Tests for these chemicals on the cerebrospinal fluid (spinal tap or lumbar puncture) may also be ordered. The diagnosis of a pineal area germ cell tumor is usually confirmed upon biopsy of the tumor after it has been removed from the patient.
The prognosis for nonseminomas is based primarily on AFP and hCG concentrations found in the blood. The lower the levels of these two chemicals in the blood, the better the prognosis.