CT showing a<unk>  of the ovary: fatty formation with a smooth boundary, with a dense part, possibly a tooth. Micrograph of a<unk>  showing tissue from all three germ layers: mesoderm (immature cartilage - left-upper), endoderm (gastrointestinal glands - center-bottom) and ectoderm (epidermis - right)<unk> s are thought to originate in utero, so can be considered congenital tumors. Many<unk> s are not diagnosed until much later in childhood or in adulthood. Large tumors are more likely to be diagnosed early on. Sacrococcygeal and cervical<unk> s are often detected by prenatal ultrasound. Additional diagnostic methods may include prenatal magnetic resonance imaging. In rare circumstances, the tumor is so large that the fetus may be damaged or die. In the case of large sacrococcygeal<unk> s, a significant portion of the fetus' blood flow is redirected toward the<unk>  (a phenomenon called steal syndrome), causing heart failure, or hydrops, of the fetus. In certain cases, fetal surgery may be indicated. Beyond the newborn period, symptoms of a<unk>  depend on its location and organ of origin. Ovarian<unk> s often present with abdominal or pelvic pain, caused by torsion of the ovary or irritation of its ligaments. A recently discovered condition where ovarian<unk> s cause encephalitis associated with antibodies against the N-methyl-D-aspartate receptor antibody (NMDAR) - often referred to as "anti-NMDA receptor encephalitis", was identified as a serious complication. Patients develop a multistage illness that progresses from psychosis, memory deficits, seizures, and language disintegration into a state of unresponsiveness with catatonic features often associated with abnormal movements, and autonomic and breathing instability. Testicular<unk> s present as a palpable mass in the testis; mediastinal<unk> s often cause compression of the lungs or the airways and may present with chest pain and/or respiratory symptoms. Some<unk> s contain yolk sac elements, which secrete alpha-fetoprotein. Its detection may help to confirm the diagnosis and is often used as a marker for recurrence or treatment efficacy, but is rarely the method of initial diagnosis. (Maternal serum alpha-fetoprotein is a useful screening test for other fetal conditions, including Down syndrome, spina bifida, and abdominal wall defects such as gastroschisis.) Classification Regardless of location in the body, a<unk>  is classified according to a cancer staging system. This indicates whether chemotherapy or radiation therapy may be needed in addition to surgery.<unk> s 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.<unk> s are also classified by their content; a solid<unk>  contains only tissues (perhaps including more complex structures); a cystic<unk>  contains only pockets of fluid or semifluid such as cerebrospinal fluid, sebum, or fat; a mixed<unk>  contains both solid and cystic parts. Cystic<unk> s usually are grade 0 and, conversely, grade 0<unk> s usually are cystic. Grades 0, 1, and 2 pure<unk> s have the potential to become malignant (grade 3), and malignant pure<unk> s have the potential to metastasize. These rare forms of<unk>  with malignant transformation may contain elements of somatic (not germ cell) malignancy such as leukemia, carcinoma, or sarcoma. A<unk>  may contain elements of other germ cell tumors, in which case it is not a pure<unk> , 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<unk>  can be pure and not malignant yet highly aggressive; this is exemplified by growing<unk>  syndrome, in which chemotherapy eliminates the malignant elements of a mixed tumor, leaving pure<unk> , which paradoxically begins to grow very rapidly. Malignant transformation A "benign" grade 0 (mature)<unk>  nonetheless has a risk of malignancy. Recurrence with malignant endodermal sinus tumor has been reported in cases of formerly benign mature<unk> , even in fetiform<unk>  and fetus in fetu. Squamous cell carcinoma has been found in a mature cystic<unk>  at the time of initial surgery. A grade 1 immature<unk>  that appears to be benign (e.g., because AFP is not elevated) has a much higher risk of malignancy, and requires adequate follow-up. This grade of<unk>  also may be difficult to diagnose correctly. It can be confused with other small round cell neoplasms such as neuroblastoma, small cell carcinoma of hypercalcemic type, primitive neuroectodermal tumor, Wilm's tumor, desmoplastic small round cell tumor, and non-Hodgkin lymphoma. A<unk>  with malignant transformation is a very rare form of<unk>  that may contain elements of somatic malignant tumors such as leukemia, carcinoma, or sarcoma. Of 641 children with pure<unk> , nine developed TMT: five carcinoma, two glioma, and two embryonal carcinoma (here, these last are classified among germ cell tumors). Extraspinal ependymoma Extraspinal ependymoma, usually considered to be a glioma (a type of nongerm cell tumor), may be an unusual form of mature<unk> .
Teratoma
Lipoma
Embryoma
Dermoid cyst
Gonadoblastoma
Spina bifida
Immature teratoma
Blastoma