Germ cell tumors are cancerous or non-cancerous tumors comprised mostly of the cells that develop in the embryo. These are the cells that will make up the reproductive system in males and females. After development they follow a midline path through the body and descend into the pelvis of the female as ovarian cells or into the scrotum of the male as testicular cells.Germ cell tumors make up about 3% of all childhood cancers. Ninety percent of germ cell tumors are gonadal which are found in the ovaries or testicles and are more common in children and adolescents.
Most of the remaining germ cell tumors such as extragonadal tumors are more common in infants, and occur when the germ cells fail to migrate to their correct destination. These germ cell tumors tend to occur in the lower back, chest and head.
Germinomas contain only immature germ cells:
Dysgerminomas, malignant germ cell tumors that are found in the ovaries, are the most common malignant ovarian germ cell tumors occurring in children and adolescents.
Seminomas are germ cell tumors that are found in the testes.
Embryonic tumors contain some cells that have already begun to develop into other tissues:
Teratomas can be either malignant or benign. Teratomas of the tail bone are the most common germ cell tumor found in children, and are about four times more common in girls than in boys.
Endodermal sinus tumors (yolk sac tumor) occur most commonly in ovaries and testicles, where they are aggressive and can spread quickly. They are the most common malignant ovarian and testicular tumors in childhood.
Choriocarcinoma is very rare, often malignant and originates in the cells of the placental chorion layer, the structure through which the fetus takes in oxygen and nourishment during pregnancy.
Embryonal carcinoma cells are malignant and most commonly found in the testicles, but can spread to other parts of the body.
Gonadoblastoma is a rare, almost always benign tumor associated with abnormal development of the reproductive organs.
Polyembryoma is a very rare, aggressive type of germ cell tumor that is usually found in the ovaries.
Most germ cell tumors are identified as a lump in the testicles or elsewhere along the midline of the body. Upon discovery of the lump, often the physician will arrange for a biopsy of the tumor.
Since germ cell tumors are unique among solid tumors in that they secrete serum tumor markers, blood tests for elevated levels of alpha feto-protein, human chorionic gonadotropin and lactate dehydrogenase are useful in diagnosis as well as in monitoring the tumor’s response to therapy.
Imaging studies, such as CT scan, MRI, X-ray, ultrasound and bone scans are also performed, depending upon the tumor’s location.
Treatment for germ cell tumors depends upon the child’s age and overall health, the types of tissues present in the tumor and its location, the child’s tolerance for specific types of procedures and the prognosis.
Treatment almost always includes surgery, but some types of germ cell tumors are also treated with chemotherapy, radiation and/or bone marrow transplantation. The introduction of platinum-based chemotherapy has improved the survival rate dramatically.