A germinoma is a cancerous growth that can present as a brain tumor, an ovarian dysgerminoma, or a testicular seminoma. In Medical Subject Headings (MeSH) parlance used by doctors and researchers, however, it actually refers to any malignancy of the brain, ovaries, testes, and mediastinum that arises from germ cells. As a group, these tumors are classified as germinomatous or seminomatous tumors.
The germ cell origin of a germinoma is the reason why it is classified as a germ cell tumor (GCT). Germ cells, or primordial cells, are capable of dividing and differentiating or specializing into other cells. Primordial cells can become differentiated into muscle cells, cardiac cells, skin cells, and brain cells. Normally, primordial germ cells allow an embryo to increase in size and become a fully developed human being. Primordial cells migrate to different organs and become fully differentiated.
Primordial cells, however, may remain due to an error in migration or a mutation that causes non-differentiation. The body cannot control the unlimited capacity of these primordial cells to multiply, thus resulting in the development of a malignant tumor. Immediate treatment is necessary upon the diagnosis of a germinoma because of the potential for it to spread or metastasize.
The location of a germinoma determines what symptoms an affected person will present to the doctor. If the tumor is located within the patient’s skull, such as in the pineal gland, hypothalamus, or thalamus of the brain, the patient usually complains of a frequent urge to vomit, blurring of vision, and headaches. Other symptoms that this patient might experience include excessive sweating, loss of appetite, irritability, restlessness, and walking or gait problems. Brain germinoma is a common case in pediatrics.
This type of tumor can also be found in the ovary of female adolescents and young adults — in fact, it is the most common type of germ cell gynecological cancer. In one-tenth of patients, both ovaries are involved, while in another tenth, one ovary has a grossly visible tumor and the other ovary has a microscopic tumor. Among men, the seminoma is considered the second most common type of testicular cancer.
A germinoma in the brain can be easily treated by radiation therapy of the brain and spine, with optional chemotherapy. This is the reason why it is sometimes likened to a benign tumor. Data show that children with brain germinoma have a 90% survival rate when they undergo proper treatment. Dysgerminoma and seminoma are treated by surgical removal, radiation therapy, and chemotherapy, and have a good prognosis when diagnosed early.
