A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone. Teratomata typically form in the ovary, testicle, or coccyx. Symptoms
Symptoms may be minimal if the tumor is small. A testicular teratoma may present as a painless lump. Complications may include ovarian torsion, testicular torsion, or hydrops fetalis.They are a type of germ cell tumor (a tumor that begins in the cells that give rise to sperm or eggs). They are divided into two types: mature and immature. Mature teratomas include dermoid cysts and are generally benign. Immature teratomas may be cancerous. Most ovarian teratomas are mature. In adults, testicular teratomas are generally cancerous. Definitive diagnosis is based on a tissue biopsy.Treatment of coccyx, testicular, and ovarian teratomas is generally by surgery. Testicular and immature ovarian teratomas are also frequently treated with chemotherapy.Teratomas occur in the coccyx in about one in 30,000 newborns, making them one of the most common tumors in this age group. Females are affected more often than males. Ovarian teratomas represent about a quarter of ovarian tumors and are typically noticed during middle age. Testicular teratomas represent almost half of testicular cancers. They can occur in both children and adults. The term comes from the Greek word for "monster" plus the "-oma" suffix used for tumors. Types
Mature teratoma
A mature teratoma is a grade 0 teratoma. They are highly variable in form and histology, and may be solid, cystic, or a combination of the two.
This indicates whether chemotherapy or radiation therapy may be needed in addition to surgery. Teratomas commonly are classified using the Gonzalez-Crussi grading system: 0 or mature (benign); 1 or immature, probably benign; 2 or immature, possibly malignant (cancerous); and 3 or frankly malignant. If frankly malignant, the tumor is a cancer for which additional cancer staging applies.Teratomas are also classified by their content; a solid teratoma contains only tissues (perhaps including more complex structures); a cystic teratoma contains only pockets of fluid or semifluid such as cerebrospinal fluid, sebum, or fat; a mixed teratoma contains both solid and cystic parts. Cystic teratomas usually are grade 0 and, conversely, grade 0 teratomas usually are cystic. Grades 0, 1, and 2 pure teratomas have the potential to become malignant (grade 3), and malignant pure teratomas have the potential to metastasize. These rare forms of teratoma with malignant transformation may contain elements of somatic (not germ cell) malignancy such as leukemia, carcinoma, or sarcoma. A teratoma may contain elements of other germ cell tumors, in which case it is not a pure teratoma, but rather is a mixed germ cell tumor and is malignant. In infants and young children, these elements usually are endodermal sinus tumor, followed by choriocarcinoma. Finally, a teratoma can be pure and not malignant yet highly aggressive;  this is exemplified by growing teratoma syndrome, in which chemotherapy eliminates the malignant elements of a mixed tumor, leaving pure teratoma, which paradoxically begins to grow very rapidly.