Preparatory Mindset
Ovarian tumours are the "silent killer" of gynaecology — the exam mindset is driven by age, morphology, and malignancy risk (2018CM exam tested). The golden rules:
- Epithelial ovarian cancer (EOC) is the most common and most lethal gynaecological malignancy — usually diagnosed late (stage III/IV) because it is silent (vague bloating, pressure); screening (CA-125/transvaginal USS) does not reduce mortality in the general population — no routine screen.
- Simple cysts are common and benign — premenopausal simple cysts <5 cm usually resolve (hormonal); a complex/mixed cystic-solid mass with ascites, nodules, or septations → malignant until proven otherwise.
- Age is the best risk predictor: benign functional cysts (reproductive age) → dermoid/endometrioma (reproductive) → EOC (perimenopausal/elderly).
- Germ cell tumours (dysgerminoma, teratoma) affect young women and are highly curable.
- Surgical staging is treatment and staging in one (H + BSO + omentectomy + peritoneal washings + lymphadenectomy) followed by platinum-based chemotherapy.
Core Concepts
1. Classification of ovarian tumours
| Category | Examples | Key features |
|---|---|---|
| Epithelial (60-70%) | Serous (most common, often bilateral, malignant), mucinous (large, borderline potential), endometrioid, clear cell | Malignant potential highest in serous; associated with BRCA1/2 (serous/高grade) |
| Germ cell (20-25%, young women) | Dysgerminoma (most common malignant germ cell), teratoma (mature = benign dermoid; immature = malignant), yolk sac tumour, choriocarcinoma | Dysgerminoma very radiosensitive/chemo-sensitive; AFP/hCG markers |
| Sex cord-stromal (5-10%) | Granulosa cell (estrohen-secreting — precocious puberty/PMB), Sertoli-Leydig (androgen-secreting — virilisation), fibroma (Meigs syndrome) | Meigs triad: fibroma + ascites + right pleural effusion (benign) |
| Metastatic (5-10%) | Krukenberg (gastric, signet-ring, bilateral), breast, colon | Bilateral solid ovarian masses |
2. Benign ovarian masses — the common presentations
| Mass | Age | USS | Notes |
|---|---|---|---|
| Functional cyst (follicular/corpus luteum) | Reproductive | Simple, thin-walled, unilocular | Resolves spontaneously — repeat scan after 2 cycles |
| Endometrioma (chocolate cyst) | Reproductive | Ground-glass/homogeneous low-level echoes | Associated with endometriosis; pain |
| Mature cystic teratoma (dermoid) | Reproductive | Fat/calcification (teeth/hair) — mixed echogenicity | Benign; torsion risk |
| Serous/mucinous cystadenoma | Perimenopausal | Simple or septated, large (mucinous can be huge) | Benign; borderline potential |
Features suggesting MALIGNANCY: age >50, complex mass (solid areas, thick septations, papillary projections, mural nodules), ascites, elevated CA-125, bilateral, omental cake, weight loss, family history (BRCA).
3. Epithelial ovarian cancer (EOC)
Epidemiology: most common gynaecological cancer death; ~75% diagnosed stage III-IV; risk — nulliparity, early menarche/late menopause, family history (BRCA1/2), Lynch syndrome, endometriosis (clear cell/endometrioid); protective — OCP, multiparity, breastfeeding, tubal ligation/salpingectomy.
Clinical ("silent"): abdominal bloating/distension, early satiety, pelvic pain, urinary frequency, fatigue; advanced — ascites, omental cake, bowel obstruction, pleural effusion; paraneoplastic (Trousseau thrombophlebitis).
Markers: CA-125 (elevated in ~80% of EOC — but not diagnostic; also ↑ in endometriosis, peritonitis, fibroids, pregnancy); HE4 (more specific); germ cell markers — AFP (yolk sac), hCG (choriocarcinoma), LDH (dysgerminoma); inhibin (granulosa).
Imaging: TVS (morphology — simple vs complex), CT chest/abdomen/pelvis for staging (omental cake, ascites, mets).
Diagnosis: imaging + markers + histology (after staging surgery / image-guided biopsy if inoperable).
Staging (FIGO — surgical): I (ovary only), II (pelvis), III (peritoneal/retroperitoneal nodes), IV (distant mets incl. pleural effusion/parenchymal liver).
Management:
- Primary cytoreductive (debulking) surgery: total hysterectomy + bilateral salpingo-oophorectomy + omentectomy + peritoneal washings/cytology + pelvic/para-aortic lymphadenectomy — goal: optimal debulking (residual disease <1 cm).
- Adjuvant chemotherapy: platinum (carboplatin) + paclitaxel × 6 cycles — standard for advanced disease; neoadjuvant chemotherapy + interval debulking for bulky disease/poor performance status.
- Maintenance: bevacizumab (VEGF), PARP inhibitors (olaparib/niraparib) for BRCA-mutated/HRD tumours — improving survival.
- Early-stage (I): stage I low-grade → surgery alone; stage I high-grade → chemo.
- Recurrence: platinum-sensitive → re-treat with platinum ± targeted; platinum-resistant → non-platinum agents, clinical trials.
Prognosis: stage I ~90% 5-yr survival; stage III ~30-40%; stage IV <20% — hence the "detect late = die early" message.
4. Germ cell tumours (young women)
- Dysgerminoma — most common malignant germ cell; radiosensitive + chemo-sensitive (bleomycin/etoposide/cisplatin — BEP); excellent prognosis.
- Immature teratoma, yolk sac (AFP+), choriocarcinoma (hCG+) — treated with surgery + BEP.
- Mature teratoma (dermoid) — benign; torsion risk; ovarian cystectomy.
5. Acute ovarian torsion — the emergency
Presentation: sudden severe unilateral lower abdominal pain ± nausea/vomiting, exquisitely tender adnexal mass, negative pregnancy test; USS — enlarged ovary, reduced Doppler flow.
Management: emergency laparoscopy — untwist (conservative, preserve ovary if viable) or oophorectomy; recurrent torsion → oophoropexy.
High-Yield Points
| Topic | Must-remember |
|---|---|
| Most common ovarian tumour | Epithelial (serous most common) |
| Most lethal gyn malignancy | Epithelial ovarian cancer (silent, late diagnosis) |
| Silent killer | Vague bloating → stage III/IV at diagnosis in ~75% |
| Malignancy features | Complex mass + ascites + CA-125 ↑ + age >50 + bilateral |
| CA-125 | Elevated in EOC but not diagnostic (endometriosis, peritonitis also ↑) |
| Dermoid | Mature teratoma — fat/teeth/calcification; torsion risk |
| Meigs syndrome | Fibroma + ascites + right pleural effusion — benign |
| Dysgerminoma | Most common malignant germ cell; chemo/radio-sensitive |
| Germ cell markers | AFP (yolk sac), hCG (choriocarcinoma), LDH (dysgerminoma) |
| EOC treatment | Debulking surgery (H+BSO+omentectomy+nodes) + carboplatin/paclitaxel |
| PARP inhibitors | BRCA/HRD-mutated EOC maintenance |
| Protective factors | OCP, multiparity, breastfeeding (↓ EOC risk) |
| Torsion | Emergency surgery — untwist or oophorectomy |
| No screening | CA-125/TVS not recommended for general population (no mortality benefit) |
Topic Summary
Ovarian tumours span benign functional cysts (resolve spontaneously), teratomas/endometriomas (reproductive age), epithelial ovarian cancer (perimenopausal/elderly, silent, lethal), and germ cell tumours (young, curable). EOC is diagnosed late because it is silent — complex mass + ascites + CA-125 elevation raise suspicion; treatment is optimal debulking surgery + carboplatin/paclitaxel + targeted maintenance (PARP inhibitors for BRCA). Germ cell tumours (dysgerminoma) are highly curable with BEP chemo. No routine screening exists. Torsion is the surgical emergency to always keep in the differential of acute pelvic pain.
LMCHK OSCE Practice — Pelvic Mass and Ascites
Station setup: A 55-year-old woman presents with 3 months of abdominal bloating, early satiety, and weight gain (ascites). Examination: large bilateral adnexal masses, ascites, omental thickening on CT. CA-125 850. USS: complex bilateral masses with solid areas and ascites.
Candidate tasks (8 min):
- Take a focused history (family history of breast/ovarian/colon cancer, BRCA testing, previous gyn surgery).
- State the most likely diagnosis — advanced epithelial ovarian cancer (bilateral complex masses + ascites + omental cake + CA-125).
- Explain the staging approach (CT chest/abdomen/pelvis; surgical staging).
- Discuss management: cytoreductive surgery (H+BSO+omentectomy+washings+nodes) followed by carboplatin/paclitaxel chemotherapy; consider neoadjuvant chemo if bulky/inoperable.
- Discuss genetic testing (BRCA) — PARP inhibitor maintenance and family screening implications.
- Prognosis counselling honestly (stage III ~30-40% 5-yr survival; but treatment improves survival significantly).
Key marking cues:
- Recognises ovarian cancer from the clinicoradiological picture (not waiting for histology).
- Knows the surgical + chemo standard.
- Raises BRCA/PARP and family screening.
- Counsels honestly about prognosis and treatment goals.