[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/) › Non-neoplastic ovarian cysts and polycystic ovaries # Non-neoplastic ovarian cysts and polycystic ovaries - Lesion Most ovarian cysts are leftovers of the normal cycle and go away. Polycystic ovaries are a sign of a hormonal syndrome, not a tumour. Updated Nov 12, 2026 ## Key points - Follicle cyst: an unruptured follicle, lined by granulosa and theca cells (granulosa may be lost); clear fluid. - Corpus luteum (luteal) cyst: rim of yellow luteinised cells; can bleed into the cyst or the peritoneum. - Theca lutein cysts: bilateral, from very high hCG (molar pregnancy, multiple pregnancy, ovulation induction). - Polycystic ovaries: enlarged ovaries, thick white capsule, many subcortical follicle cysts with hyperplastic luteinised theca interna, no corpora lutea. - Polycystic ovary syndrome: anovulation, androgen excess and insulin resistance; risk of endometrial hyperplasia and carcinoma, type 2 diabetes. - Stromal hyperthecosis: both ovaries enlarged and solid with nests of luteinised stromal cells; virilisation after menopause. ## What it is The ovary forms a follicle and a corpus luteum every cycle, and either can persist as a functional cyst. Follicle and luteal cysts are common, usually resolve, and matter when they bleed, rupture or twist. Polycystic ovaries, with many subcortical cysts under a thick capsule, are the ovarian picture of polycystic ovary syndrome, a disorder of anovulation, androgen excess and insulin resistance. Stromal hyperthecosis is a related, usually postmenopausal, form of androgen excess from luteinised stromal cells. ## Structure - Follicle cysts are usually small, thin-walled and multiple. - Luteal cysts have a convoluted yellow wall and may contain blood clot. - Polycystic ovaries: a pearly thick capsule over a string of cysts in the cortex; the stroma is often increased. - Hyperthecosis: nodules of cells with lipid-rich cytoplasm scattered in a hyperplastic stroma. ## Step by step - In polycystic ovary syndrome, LH is high relative to FSH and insulin resistance raises insulin. - LH and insulin drive the theca cells to make androgens. - Excess androgens and too little FSH stop follicles from maturing, so many small follicles arrest as cysts and no corpus luteum forms. - Without ovulation there is no progesterone; estrogen from converted androgens acts unopposed on the endometrium. - Results: irregular periods, hirsutism and acne, infertility, endometrial hyperplasia and metabolic disease. ## Clinical notes - Functional cysts may cause pain, haemorrhage or torsion; most resolve over a few cycles. - Polycystic ovary syndrome is the most common cause of anovulatory infertility; its diagnosis is clinical and hormonal, not just ultrasound. - Virilisation that begins late or progresses rapidly suggests hyperthecosis or an androgen-secreting tumour. ## Memory aid A follicle that will not burst becomes a cyst; a syndrome where none can burst becomes a necklace of cysts. ## Test yourself Think of the answer, then tap the question to see it. ## What do polycystic ovaries look like? Enlarged with a thick white capsule and many subcortical follicle cysts with hyperplastic luteinised theca interna, and no corpora lutea. ## What produces theca lutein cysts? Very high hCG, as in molar pregnancy, multiple pregnancy or ovarian stimulation. ## Why does polycystic ovary syndrome raise the risk of endometrial carcinoma? Chronic anovulation leaves the endometrium exposed to estrogen without progesterone, causing hyperplasia and carcinoma. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/general-pathology/non-neoplastic-ovarian-cysts-and-polycystic-ovaries/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Elsewhere in DurgiPedia - [Ovary: follicles, ovulation and corpus luteum](https://durgical.com/en/histology/ovary-follicles-ovulation-and-corpus-luteum/) - [Ovarian cycle, ovulation and the corpus luteum](https://durgical.com/en/embryology/ovarian-cycle-ovulation-and-the-corpus-luteum/) - [The menstrual cycle: ovary and endometrium](https://durgical.com/en/physiology/the-menstrual-cycle-ovary-and-endometrium/) - [Steroid hormone synthesis (overview)](https://durgical.com/en/biochemistry/topics/steroid-hormone-synthesis/) ## Connections ## Related 6 - [Endometrium and abnormal uterine bleeding](https://durgical.com/en/general-pathology/endometrium-and-abnormal-uterine-bleeding/) - [Endometrial polyps and hyperplasia](https://durgical.com/en/general-pathology/endometrial-polyps-and-hyperplasia/) - [Hydatidiform mole: complete vs partial](https://durgical.com/en/general-pathology/hydatidiform-mole-complete-vs-partial/) - [Other sex cord–stromal tumours](https://durgical.com/en/general-pathology/other-sex-cord-stromal-tumours/) - [Ovarian tumours: classification](https://durgical.com/en/general-pathology/ovarian-tumours-classification/) - [Obesity: leptin, adipokines and its consequences](https://durgical.com/en/general-pathology/obesity-leptin-adipokines-and-its-consequences/) ## Related conditions 8 - [Ovarian cyst](https://durgical.com/en/conditions/ovarian-cyst/) - [Polycystic ovary syndrome](https://durgical.com/en/conditions/polycystic-ovary-syndrome/) - [Ovarian torsion](https://durgical.com/en/conditions/ovarian-torsion/) - [Ovarian hyperstimulation syndrome](https://durgical.com/en/conditions/ovarian-hyperstimulation-syndrome/) - [Female infertility](https://durgical.com/en/conditions/female-infertility/) - [Endometrial hyperplasia](https://durgical.com/en/conditions/endometrial-hyperplasia/) - [Type 2 diabetes mellitus](https://durgical.com/en/conditions/type-2-diabetes-mellitus/) - [Molar pregnancy (hydatidiform mole)](https://durgical.com/en/conditions/molar-pregnancy/) [← 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 Cyst](https://www.ncbi.nlm.nih.gov/books/NBK560541/) (StatPearls (NCBI Bookshelf), 2026); [Polyendocrine Metabolic Ovarian Syndrome](https://www.ncbi.nlm.nih.gov/books/NBK459251/) (StatPearls (NCBI Bookshelf), 2026); [Polycystic ovary syndrome: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/polycystic-ovary-syndrome/) (MedlinePlus, US National Library of Medicine, 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/non-neoplastic-ovarian-cysts-and-polycystic-ovaries/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/non-neoplastic-ovarian-cysts-and-polycystic-ovaries/