[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Female genital tract](https://durgical.com/en/general-pathology/areas/female-genital/) › Ovarian teratomas # Ovarian teratomas - Lesion A teratoma grows hair, skin, teeth and even brain. The mature cyst is benign; the immature one, of young girls, is a cancer graded by its brain tissue. Updated Nov 12, 2026 ## Key points - Mature cystic teratoma: unilocular cyst with hair and greasy sebum, a nodule (Rokitansky protuberance) holding teeth, bone, cartilage, neural or thyroid tissue; bilateral in a minority. - It arises from a germ cell after the first meiotic division: typically 46,XX. - Complications: torsion, rupture with chemical peritonitis, malignant transformation (usually squamous carcinoma in older women), and anti-NMDA receptor encephalitis from neural tissue. - Immature teratoma: mainly solid; immature neuroepithelium forming rosettes and tubules; graded by its amount. - Struma ovarii: mostly thyroid tissue, can cause hyperthyroidism; ovarian carcinoid can cause carcinoid syndrome without liver metastases. ## What it is Teratomas are germ cell tumours that differentiate into tissues of more than one germ layer. The mature cystic teratoma (dermoid cyst) is the most common ovarian tumour of young women: a benign cyst lined by skin with hair, sebum, teeth and other mature tissues. Immature teratoma, of children and young women, contains embryonal-type tissue, mostly primitive neuroepithelium, and is malignant. Monodermal teratomas are made of a single tissue, such as thyroid (struma ovarii) or neuroendocrine cells (carcinoid), and can cause hormone syndromes. ## Structure - Dermoid cyst wall: keratinizing squamous epithelium with hair follicles and sebaceous and sweat glands; beneath it any mature tissue may appear. - Rupture of contents provokes foreign-body granulomas. - Immature teratoma: fleshy, solid, haemorrhagic mass; primitive neuroepithelium among other immature and mature tissues. - Struma ovarii: brown solid tissue of thyroid follicles with colloid. ## Step by step - A germ cell completes the first meiotic division and then begins to divide on its own (parthenogenetic origin). - Its descendants differentiate along ectodermal, mesodermal and endodermal lines. - Fully differentiated tissues form a benign mature teratoma; persisting embryonal tissue makes an immature teratoma. - Rarely, one tissue in a mature teratoma becomes malignant, or neural tissue triggers autoimmunity against NMDA receptors. ## Clinical notes - Mature teratomas are often incidental; they are a leading cause of ovarian torsion in young women. - A young woman with psychiatric symptoms, seizures and dyskinesias should be checked for an ovarian teratoma; removing it improves anti-NMDA receptor encephalitis. - Immature teratomas are treated with surgery and, for higher grades, chemotherapy; prognosis depends on grade and stage. ## Memory aid A dermoid is a handbag with hair, grease and teeth; an immature teratoma is the same bag still packing brain. ## Test yourself Think of the answer, then tap the question to see it. ## What is the karyotype and origin of a mature cystic teratoma? Usually 46,XX; it arises from a germ cell after the first meiotic division. ## Which tissue grades an immature teratoma? The amount of immature (primitive) neuroepithelium. ## Which autoimmune encephalitis is associated with ovarian teratoma? Anti-NMDA receptor encephalitis, triggered by neural tissue in the teratoma. ## What is struma ovarii? A monodermal teratoma composed mostly of thyroid tissue, which can cause hyperthyroidism. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/general-pathology/ovarian-teratomas/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Connections ## Related 7 - [Malignant ovarian germ cell tumours](https://durgical.com/en/general-pathology/malignant-ovarian-germ-cell-tumours/) - [Ovarian tumours: classification](https://durgical.com/en/general-pathology/ovarian-tumours-classification/) - [Mucinous ovarian tumours](https://durgical.com/en/general-pathology/mucinous-ovarian-tumours/) - [Nonseminomatous germ cell tumours](https://durgical.com/en/general-pathology/nonseminomatous-germ-cell-tumours/) - [Naming tumours: -oma, carcinoma, sarcoma, and the misleading names](https://durgical.com/en/general-pathology/naming-tumours-oma-carcinoma-sarcoma-and-the-misleading-names/) - [Paraneoplastic syndromes: the table to know](https://durgical.com/en/general-pathology/paraneoplastic-syndromes-the-table-to-know/) - [Tumours of infancy and childhood](https://durgical.com/en/general-pathology/tumours-of-infancy-and-childhood/) ## Related conditions 5 - [Ovarian germ-cell and sex cord–stromal tumours](https://durgical.com/en/conditions/ovarian-germ-cell-and-sex-cord-stromal-tumours/) - [Ovarian torsion](https://durgical.com/en/conditions/ovarian-torsion/) - [Autoimmune encephalitis (including anti-NMDA receptor encephalitis)](https://durgical.com/en/conditions/autoimmune-encephalitis/) - [Graves disease (hyperthyroidism)](https://durgical.com/en/conditions/graves-disease/) - [Ovarian cyst](https://durgical.com/en/conditions/ovarian-cyst/) [← All of general pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Ovarian Germ Cell Tumors Treatment (PDQ®)–Health Professional Version](https://www.cancer.gov/types/ovarian/hp/ovarian-germ-cell-treatment-pdq) (National Cancer Institute, 2026); [Ovarian Torsion](https://www.ncbi.nlm.nih.gov/books/NBK560675/) (StatPearls (NCBI Bookshelf), 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/general-pathology/ovarian-teratomas/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/ovarian-teratomas/