Ovarian cysts and benign ovarian tumours
How a follicle or corpus luteum becomes a functional cyst, how the ovary’s epithelial, germ and stromal cells give rise to benign tumours such as cystadenomas and dermoid cysts, and why a cyst can bleed, burst or twist.
By the end, you can
- Relate the three cell families of the ovary to the main groups of ovarian tumour.
- Explain how follicular, corpus luteum and theca lutein cysts form, and why most resolve.
- Describe serous and mucinous cystadenomas and the mature cystic teratoma, including their gross and microscopic appearance.
- Explain how some stromal tumours and teratomas produce hormones and what effects follow.
- Explain the mechanisms of rupture, haemorrhage and torsion and the findings they cause.
What it is
An ovarian cyst is a fluid-filled sac in or on the ovary. Most in the reproductive years are functional cysts, exaggerations of the normal cycle that resolve on their own. Benign ovarian tumours are true neoplasms that do not invade: epithelial tumours such as serous and mucinous cystadenomas, germ cell tumours such as the mature cystic teratoma (dermoid cyst), and sex cord–stromal tumours such as the fibroma and thecoma.
5 types to tell apart
- Functional cysts
- Follicular and corpus luteum cysts, which arise from the ovulatory cycle and usually disappear within a few cycles; theca lutein cysts form under high hCG.
- Endometrioma
- A cyst lined by endometrial tissue and filled with old blood ("chocolate cyst"), a form of endometriosis rather than a tumour.
- Epithelial tumours
- Serous and mucinous cystadenomas, cystadenofibromas and Brenner tumours; the benign end of a range that includes borderline tumours and carcinomas.
- Germ cell tumours
- The mature cystic teratoma (dermoid cyst), containing mature tissues from all three germ layers; the commonest ovarian tumour in young women.
- Sex cord–stromal tumours
- Fibroma and thecoma, solid tumours of the ovarian stroma; thecomas often make oestrogen.
US spelling: tumours → tumors.
Normal function
The ovary and its three cell families
Each has an outer cortex packed with follicles and an inner medulla of vessels and loose tissue, covered by a single layer of flat to cuboidal surface epithelium. Three cell families live there: the germ cells (oocytes), the sex cord–stromal cells that surround them (granulosa and theca cells) and the spindle cells of the stroma, and the surface epithelium, related to the lining of the .
Each cycle a follicle grows into a fluid-filled sac about 2 cm across, ruptures at ovulation and releases its egg. The emptied follicle becomes the corpus luteum, which makes progesterone and, without pregnancy, shrinks to a scar (corpus albicans) in about two weeks.
Each cell family can give rise to its own group of tumours. Their structure follows the cell of origin: epithelial tumours form cysts lined by glandular cells, germ cell tumours can form any tissue of the body, and stromal tumours are solid.
| Feature | Benign examples | Borderline or malignant relatives |
|---|---|---|
| Epithelium (Müllerian or tubal type) | Serous and mucinous cystadenoma, cystadenofibroma, Brenner tumour | Borderline tumours; serous, mucinous, endometrioid and clear cell carcinoma |
| Germ cells | Mature cystic teratoma (dermoid cyst) | Dysgerminoma, yolk sac tumour, immature teratoma |
| Sex cord–stromal cells | Fibroma, thecoma | Granulosa cell tumour; some Sertoli–Leydig cell tumours |
| Other organs | None | Metastases, e.g. from the stomach, bowel or breast |
Simplified from the WHO classification. Epithelial tumours are commonest overall; the dermoid cyst is commonest in young women.
Underlying change · Step 1 of 5
Functional cysts: the cycle overshoots
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Underlying change · Step 2 of 5
Epithelial tumours: cystadenomas
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Underlying change · Step 3 of 5
The mature cystic teratoma (dermoid cyst)
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 4 of 5
Solid stromal tumours and hormone effects
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 5 of 5
Bleeding, rupture and torsion
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 5 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 8 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .