How Are Germ Cell Tumors Diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for germ cell tumors may include:
A sample of tissue is removed from the tumor and examined under a microscope.
Complete blood count (CBC)
A measurement of size, number, and maturity of different blood cells in a specific volume of blood.
Additional blood tests
May include blood chemistries, evaluation of liver and kidney functions, genetic studies and measurement of AFP and B-HCG.
Computed tomography scan (also called a CT or CAT scan)
A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
Magnetic resonance imaging (MRI)
A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
A diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones and organs onto film.
Ultrasound (also called sonography)
A diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
Pictures or X-rays taken of the bone after a dye has been injected that is absorbed by bone tissue. These are used to detect tumors and bone abnormalities.
Diagnosis of germ cell tumors depends on the types of cells involved. The most common types of germ cell tumors include:
Teratomas contain cells from the three germ layers: ectoderm, mesoderm and endoderm. Teratomas can be malignant or benign, depending on the maturity and other types of cells that may be involved. Teratomas are the most common germ cell tumor found in the ovaries. Sacrococcygeal (tail bone, or distal end of spinal column) teratomas are the most common germ cell tumors found in childhood. Because these sacrococcygeal tumors are often visible from the outside of the body, diagnosis is made early and treatment and/or surgery are initiated early, making the prognosis for this type of germ cell tumor very favorable.
Germinomas are malignant germ cell tumors. Germinomas are also termed dysgerminoma when located in the ovaries and seminoma when located in the testes. Among children, germinoma, or dysgerminoma, occurs most frequently in the ovary of a pre-pubescent or adolescent female. Dysgerminoma is the most common malignant ovarian germ cell tumor seen in children and adolescents.
Endodermal Sinus Tumor or Yolk Sac Tumors
Endodermal sinus tumor or yolk sac tumors are germ cell tumors that are most often malignant, but may also be benign. These tumors are most commonly found in the ovary, testes and sacrococcygeal areas (tail bone, or distal end of spinal column). When found in the ovaries and testes, they are often very aggressive, malignant and can spread rapidly through the lymphatic system and other organs in the body. Yolk sac tumors are the most common malignant testicular and ovarian tumors in children. Most yolk sac tumors will require surgery and chemotherapy, regardless of stage or presence of metastasis, because of the aggressive nature and recurrence of the disease.
Choriocarcinoma is a very rare, but often malignant germ cell tumor that arises from the cells in the chorion layer of the placenta (during pregnancy, a blood-rich structure through which the fetus takes in oxygen, food and other substances while getting rid of waste products). These cells may form a tumor in the placental cells during pregnancy and spread (metastasize) to the infant and mother. When the tumor develops during pregnancy, it is called gestational choriocarcinoma. Gestational choriocarcinoma most often occurs in pregnant females that are between 15- and 19-years-old. If a nonpregnant young child develops choriocarcinoma from the chorion cells that originated from the placenta that are still in the body, the term used is nongestational choriocarcinoma.
Embryonal carcinoma cells are malignant cells that are usually mixed with other types of germ cell tumors. They occur most often in the testes. These types of cells have the ability to spread to other parts of the body. When these cells are mixed with an otherwise benign type of tumor (mature teratoma), the presence of embryonal carcinoma cells will cause it to become malignant (cancerous).
Many germ cell tumors have multiple types of cells involved. The diagnosis, treatment and prognosis are based on the most malignant of the cells present and the majority type of cells that are present.