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🔬 GERM CELL TUMOURS (GCTs) OF THE OVARY

Comprehensive Exam Study Material (2025/2026 Edition)

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OVERVIEW & CLASSIFICATION

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STAGING SURGERY PRINCIPLES

• Unilateral salpingo-oophorectomy (USO) - preferred
• Peritoneal cytology
• Inspection/biopsy of peritoneal surfaces, omentum, lymph nodes
• Biopsy of contralateral ovary only if macroscopically abnormal
• MaGIC group minimum requirement: Intact tumor removal + peritoneal inspection + cytology

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1. DYSGERMINOMA

Epidemiology & Key Facts

• Most common malignant GCT (~30-40% of all malignant GCTs)
• Only 1-3% of all ovarian cancers; 5-10% in women <20 years
• 75% occur between ages 10-30 years; rarely after age 50
• 20-30% of ovarian malignancies associated with pregnancy
• Only GCT with significant bilaterality rate: 10-15% of stage I tumours are bilateral
• 65% are stage I at diagnosis

Associations

• Gonadal dysgenesis (45,X/46,XY karyotype, streak gonads)
• Androgen insensitivity syndrome (46,XY, testicular feminization)
• Gonadoblastoma - >50% malignant transformation if left in situ
• Karyotype must be checked preoperatively in premenarcheal patients
• If Y chromosome found: bilateral oophorectomy (uterus preserved for embryo transfer)

Pathology

• Gross: 5-15 cm, bosselated capsule, fleshy pale-tan to gray-brown cut surface, principally solid with cystic/necrotic areas
• Histology: Large, round/polygonal cells with abundant clear cytoplasm, large irregular nuclei, prominent nucleoli; arranged in lobules/nests separated by fibrous septa infiltrated with lymphocytes, plasma cells, granulomas (can mimic TB if extensive necrosis)
• IHC: OCT3/4 (+), NANOG (+), SALL4 (+), CD117/KIT (+), PLAP (+), D2-40 (+)
• May contain syncytiotrophoblastic giant cells (associated with precocious puberty/virilization - does NOT alter prognosis)
• Calcifications: suggest underlying gonadoblastoma

• Size >10-15 cm
• Age <20 years
• Numerous mitoses, anaplasia, medullary pattern

Spread Pattern

• Predominantly lymphatic (para-aortic, then mediastinal/supraclavicular nodes - late)
• Hematogenous/peritoneal spread less common
• Bone metastases: lower vertebrae
• Lung/liver/brain: longstanding or recurrent disease

Tumor Markers

• LDH: Elevated in 95% - primary monitoring marker
• PLAP: Elevated in 95%
• β-hCG: Only if syncytiotrophoblastic cells present
• AFP: Negative (if positive, suggests mixed GCT)

Treatment

Surgery

• USO (minimal procedure) - fertility preservation almost always desired
• Contralateral ovary/tube/uterus preserved even with metastatic disease (chemo-sensitive)
• Contralateral ovary biopsy only if macroscopically abnormal
• 5-10% contralateral ovary involvement over 2 years in stage I (includes those with gonadal dysgenesis)

Chemotherapy Indications (NCCN 2025)

BEP Regimen

• Bleomycin 30 IU IV weekly
• Etoposide 100 mg/m² days 1-5
• Platinum (cisplatin) 20 mg/m² days 1-5
• Repeat every 21 days
• Pulmonary function tests BEFORE starting (bleomycin lung toxicity)
• Low/Intermediate risk: 3 cycles; High risk: 4 cycles

Alternative for Dysgerminoma (Reduced Toxicity)

• Carboplatin + Etoposide (CE) - omits bleomycin; pooled analysis shows comparable efficacy with reduced toxicity; particularly when bleomycin contraindicated

Radiation (historical)

• Dysgerminoma is highly radiosensitive (was standard before BEP era)
• Now replaced by chemotherapy (fertility preservation, less toxicity)
• Role: salvage in select cases

Prognosis

• Stage I with surgery alone: >95% 5-year disease-free survival
• Overall: excellent; even metastatic disease is highly curable with BEP
• Recurrence in <10% of properly staged Stage I disease on surveillance

NCCN 2025 Surveillance (Post-Treatment)

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2. YOLK SAC TUMOUR (Endodermal Sinus Tumour - EST)

Epidemiology & Key Facts

• Third most common malignant GCT
• Median age: 16-18 years (~1/3 are premenarcheal)
• Most common symptom: abdominal/pelvic pain (~75%)
• Asymptomatic pelvic mass: ~10%
• Always unilateral (100%) - biopsy of contralateral ovary is contraindicated
• Associated with gonadal dysgenesis - chromosomal analysis needed in premenarcheal patients

Pathology

• Gross: Soft, grayish-brown; cystic areas due to degeneration/necrosis; intact capsule in most cases
• Histology (Pathognomonic Feature): Schiller-Duval body - a glomerulus-like tuft with a central vascular core projecting into a cystic space lined by flattened/irregular endothelium
• Reticular/myxoid pattern simulating undifferentiated mesoblast
• Hobnail appearance of papillary lining (mimics clear cell carcinoma)
• IHC: AFP (+), Glypican-3 (+), SALL4 (+), OCT3/4 (-)

Tumor Markers

• AFP: Markedly elevated in almost all cases (primary diagnostic and monitoring marker)
• Good correlation between disease extent and AFP level (discordance can occur)
• Alpha-1 antitrypsin (AAT): rarely elevated
• Serial AFP monitoring is the cornerstone of follow-up

Subtypes (Histologic Patterns)

1. Endodermal sinus pattern (classic - Schiller-Duval bodies)
2. Reticular/microcystic
3. Solid
4. Alveolar-glandular
5. Polyvesicular vitelline
6. Myxomatous
7. Hepatoid (AFP strongly positive, worse prognosis)
8. Parietal (hyaline globules - periodic acid-Schiff positive)

Treatment

Surgery

• USO (fertility-sparing)
• Full staging: peritoneal cytology, omentectomy, lymph node sampling

Chemotherapy (NCCN 2025)

• ALL stages require adjuvant BEP (even Stage I)
• This distinguishes YST from dysgerminoma (no surveillance option)
• Rationale: Prior to cisplatin era, Stage I YST had <10% survival; BEP dramatically improved this to >95%

BEP Protocol

• 3 cycles for Stage I-II (good/intermediate risk per IGCCCG)
• 4 cycles for Stage III-IV (high risk)
• Modified IGCCCG risk stratification applies

Prognosis

• With BEP: Stage I-II: >95% 5-year survival
• Advanced stage (III-IV): 60-75% with BEP
• Hepatoid variant: Poorer prognosis; higher AFP, more aggressive
• AFP normalization is the key treatment response endpoint

Recurrence Management

• ~10% of all MOGCTs will relapse
• Salvage: TIP (paclitaxel/ifosfamide/cisplatin) or VIP (vinblastine/ifosfamide/cisplatin)
• High-dose chemotherapy (HDCT) + autologous stem cell transplant (ASCT) for platinum-resistant/refractory disease (specialized centers)
• Cytoreductive surgery for resectable relapse

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3. IMMATURE TERATOMA

Epidemiology & Key Facts

• Second most common malignant GCT
• Pure form: <1% of all ovarian cancers; 10-20% of ovarian malignancies in women <20 years
• ~50% occur between ages 10-20 years; rarely in postmenopausal women
• Always unilateral (bilateral occurrence is extremely rare)
• Mature teratoma (dermoid cyst) is the most common benign GCT

Pathology & Grading

• Contains embryo-derived immature elements (especially neural tissue)
• The maturation status determines behavior: abnormal maturation = metastatic potential
• Grading based on amount of immature neuroepithelium per low-power field (x4 objective):

Norris Grading System (Classic 3-tier):

Modern 2-Tier System (Recommended due to inter-observer variability):

• Low Grade: Equivalent to Norris Grade 1
• High Grade: Equivalent to Norris Grades 2-3

Gliomatosis Peritonei

• Mature glial implants on peritoneal surfaces
• Favorable prognostic finding if composed of completely mature tissues
• Molecular studies suggest these are NOT tumor-derived but represent teratoma-induced metaplasia of pluripotent Müllerian stem cells in the peritoneum
• Does NOT upstage the disease

Tumor Markers

• AFP: May be mildly elevated
• β-hCG: Usually negative
• Markers rarely markedly elevated (if so, consider mixed GCT)

Treatment (NCCN 2025)

Key Nuance for Pediatric Patients:

• ESGO young adult guidelines suggest surveillance even for higher grades in children due to excellent surgery-alone outcomes
• MaGIC consortium data: onset at/after age 11 is a risk factor for poorer prognosis

Growing Teratoma Syndrome (GTS)

• Definition: Enlarging masses during/after chemotherapy in a patient with normalizing/normalized tumor markers, composed entirely of mature teratoma
• Not malignant transformation - represents selective chemotherapy killing of malignant elements
• Treatment: Surgical resection (chemo does not help mature elements)
• Laparoscopic-assisted fertility-sparing approach is feasible at specialized centers (PMID: 39074547)

Prognosis

• Overall 5-year survival (all stages): 70-80%
• Stage I surgically staged: 90-95%
• Grade is the most important prognostic factor

Recent Evidence (2024, PMID: 38371620)

• Stage I immature teratoma: outcomes after surveillance vs adjuvant chemo comparable; surveillance associated with preserved fertility without compromising oncologic outcomes

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4. EMBRYONAL CARCINOMA

Epidemiology & Key Facts

• Extremely rare - one of the rarest GCTs
• Very young patients: ages 4-28 years
• Often presents with signs of isosexual precocity (estrogen secretion)
• Differentiated from choriocarcinoma by absence of syncytiotrophoblastic and cytotrophoblastic cells

Pathology

• Gross: Solid, necrotic, hemorrhagic
• Histology: Large primitive cells with vesicular nuclei, prominent nucleoli; arranged in sheets, glands, or papillae; no trophoblastic differentiation
• IHC: OCT3/4 (+), NANOG (+), SALL4 (+), CD30 (+), AFP (+), β-hCG (+) - both AFP and hCG positive (key distinguishing feature)

Tumor Markers

• AFP: Elevated
• β-hCG: Elevated
• Both positive simultaneously differentiates from pure dysgerminoma (neither) or pure choriocarcinoma (only hCG)

Treatment

• BEP x 3-4 cycles for ALL stages (per NCCN 2025)
• Surgery: USO + staging
• No surveillance option

Prognosis

• Aggressive behavior
• Prognosis depends on stage; responds to BEP
• Limited data due to rarity

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5. NON-GESTATIONAL CHORIOCARCINOMA

Epidemiology & Key Facts

• Extremely rare pure non-gestational choriocarcinoma
• Most patients: <20 years
• Distinguishing from gestational choriocarcinoma is essential (histologically identical, but non-gestational origin = worse prognosis, less responsive to gestational regimens)
• ~50% develop isosexual precocity if tumor appears before menarche (due to very high hCG)
• Frequently has metastases to organ parenchyma at diagnosis (poor prognosis)

Pathology

• Histology: Biphasic pattern of cytotrophoblast (mononuclear, pale) and syncytiotrophoblast (multinuclear, eosinophilic) - same appearance as gestational choriocarcinoma
• No Schiller-Duval bodies (differentiates from YST)
• IHC: β-hCG (+), HPL (+), p63 (+, in cytotrophoblast), AFP (-)
• Molecular: Non-gestational confirmed by DNA fingerprinting or STR analysis (no paternal DNA in non-gestational)

Tumor Markers

• β-hCG: Markedly elevated (primary marker)
• AFP: Negative

Treatment (NCCN 2025)

• BEP x 3-4 cycles for ALL stages
• Alternative: MAC regimen (Methotrexate, Actinomycin D, Cyclophosphamide) - as used in gestational trophoblastic disease
• Important: Response to MAC (GTD regimens) is inferior compared to gestational choriocarcinoma

Prognosis

• Poor overall prognosis - most patients have organ parenchymal metastases at diagnosis
• Worse prognosis than gestational choriocarcinoma (less responsive to anti-GTD regimens)
• Systematic review 2022 (PMID: 35328112): median survival <12 months in advanced disease

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6. POLYEMBRYOMA

Epidemiology

• Exceedingly rare - very few documented cases
• Very young, premenarcheal girls
• Signs of pseudopuberty (hormonal)

Pathology

• Composed of embryoid bodies - replicates early embryonic differentiation (endoderm, mesoderm, ectoderm - all three somatic layers)
• IHC: AFP (+), β-hCG (+)

Tumor Markers

• AFP: Elevated
• β-hCG: Elevated

Treatment

• Same principles as other primitive GCTs
• BEP chemotherapy; USO + staging surgery

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7. MIXED GERM CELL TUMOURS

Definition & Composition

• Contain two or more GCT elements
• Most common component: Dysgerminoma (80%), followed by EST (70%), immature teratoma (53%), choriocarcinoma (20%), embryonal carcinoma (16%)
• Most frequent combination: Dysgerminoma + EST

Tumor Markers

• Variable - depends on components present
• Monitor all relevant markers (AFP and/or β-hCG based on components)
• Marker normalization on chemo may reflect regression of only one component - residual viable tumor may remain

Prognosis

• Stage IA, size <10 cm: 100% survival
• Most malignant component determines prognosis:
  • <1/3 EST, choriocarcinoma, or Grade 3 IT: excellent prognosis

  • 1/3 of above: less favorable

Treatment

• BEP for all stages

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8. GONADOBLASTOMA (Precursor Lesion)

Key Facts

• Benign but precancerous lesion
• Composed of germ cells + sex cord stroma
• Occurs in patients with gonadal dysgenesis (45,X/46,XY or pure gonadal dysgenesis 46,XY)
• >50% develop malignancy if left in situ
• Calcifications on imaging should prompt search for gonadoblastoma
• Treatment: Bilateral gonadectomy (bilateral streak gonads/dysgenetic gonads)

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BEP REGIMEN - DETAILS & TOXICITY

Dosing

• Bleomycin: 30 IU IV on Days 1, 8, 15 (weekly)
• Etoposide: 100 mg/m² IV Days 1-5
• Cisplatin: 20 mg/m² IV Days 1-5
• Cycle length: 21 days
• Duration: 3 cycles (low/intermediate risk) or 4 cycles (high risk)

Pre-treatment Requirements (NCCN 2025)

• Pulmonary function tests (PFTs) before bleomycin
• Renal function (cisplatin nephrotoxicity)
• Audiometry (cisplatin ototoxicity)
• ECHO/ECG (baseline cardiovascular)

Toxicity Profile

Late Effects of BEP (Long-Term)

• Renal dysfunction
• Gonadal dysfunction (most important for young women)
• Peripheral neurotoxicity
• Cardiovascular toxicity (long-term)
• Secondary malignancies (AML with etoposide)
• However: majority of fertility preserved if contralateral ovary intact

Fertility Data (PMID: 41068325 - Systematic Review 2025)

• Fertility-sparing surgery + BEP: majority of patients retain normal menstrual function and achieve pregnancy
• 75-90% menstrual function restoration post-BEP

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RISK STRATIFICATION

Modified IGCCCG Criteria for MOGCTs (Extrapolated from testicular GCTs)

Note: Advanced-stage MOGCTs (except dysgerminoma) mostly fall into intermediate or high risk.

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RECURRENT/REFRACTORY DISEASE

Epidemiology

• ~10% of MOGCTs will relapse (PMID: 38991656, Nasioudis 2024)

Salvage Chemotherapy Options

Secondary Surgery

• Cytoreductive surgery for patients with surgically resectable residual/relapsed disease
• Goal: complete gross resection or optimal resection
• Carefully selected patients only

Prognosis in Relapse

• Worse than testicular GCT relapse outcomes
• Platinum-resistant relapse: poor prognosis
• HDCT + ASCT: shows promise; optimal timing under investigation (PMID: 40275685)

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RECENT ADVANCES & NOVEL APPROACHES (2021-2026)

1. KIT Inhibitors in Dysgerminoma

• ~25-30% of dysgerminomas harbor KIT (CD117) activating mutations (exon 17 most common)
• Imatinib/Sunitinib have been explored - limited success so far; remain experimental (PMID: 40275685)
• Ongoing research needed; currently not standard of care

2. Molecular & Genomic Landscape

• Single-cell profiling studies (PMID: 40269311, 2025): identified distinct transcriptomic profiles for each GCT subtype
• Dysgerminoma: OCT3/4, NANOG, KIT pathway
• YST: AFP-producing, Glypican-3, Wnt signaling
• Actionable genomic alterations found in a subset - targeted therapy potential under exploration

3. Surveillance vs Chemotherapy for Stage I Disease

• Growing evidence supporting observation for Stage I dysgerminoma and Stage I Grade 1 IT (PMID: 38371620, Marino 2024)
• 2024 study: Stage I immature teratoma - outcomes after surveillance equivalent to adjuvant chemo; better fertility preservation
• NCCN 2025 endorses this approach

4. Neoadjuvant Chemotherapy (NACT)

• Role in advanced-stage MOGCT remains uncertain (PMID: 40020416, Seckl 2025)
• Some retrospective data support NACT in unresectable advanced disease
• Not currently standard; primary surgery + adjuvant BEP remains standard

5. Fertility Preservation Advances

• Systematic review 2025 (PMID: 41068325): fertility-sparing surgery safe for all GCT types regardless of stage
• Ovarian tissue cryopreservation before chemotherapy: emerging option
• Growing Teratoma Syndrome management: laparoscopic fertility-sparing resection feasible

6. HDCT + ASCT for Relapsed Disease

• Expanding evidence for high-dose carboplatin-based regimens + ASCT in refractory MOGCTs
• Evidence largely extrapolated from testicular GCT (Indiana University/GETUG trials)
• Optimal timing (upfront vs later lines) under active investigation

7. Immunotherapy

• Limited published data in MOGCTs
• PD-L1 expression variable across subtypes
• Checkpoint inhibitors: occasional responses reported; no approved indication

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GUIDELINE SUMMARY COMPARISON

NCCN 2025

ESMO/ESGO Non-Epithelial Ovarian Cancer Guidelines (2023-2024)

• Consistent with NCCN on BEP as standard regimen
• Emphasize referral to specialized centres (multidisciplinary, including paediatric and adult expertise)
• Endorse fertility-sparing surgery for all stages
• ESGO Young Adult Guidelines (2019): BEP 3-4 cycles for Stage III-IV; bleomycin omitted after cycle 3 (max cumulative dose 270 IU) to avoid pulmonary toxicity
• IGCCCG stratification recommended for treatment planning
• For Stage I dysgerminoma with minimal residual disease post-chemo: careful surveillance acceptable (residual may be non-viable)
• Acknowledge lack of randomized trial data; most evidence from retrospective/registry studies

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KEY TRIALS & LANDMARK STUDIES

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HIGH-YIELD EXAM MNEMONICS

"DYCE MIX" - Types of Primitive GCTs

Schiller-Duval Body = YST

Tumor Markers Summary

• AFP only = Yolk sac tumor
• β-hCG only = Choriocarcinoma
• Both AFP + hCG = Embryonal carcinoma
• LDH + PLAP = Dysgerminoma
• Nothing specific = Immature teratoma (mild AFP possible)

Bilaterality

• Only Dysgerminoma is significantly bilateral (10-15%)
• All others: essentially unilateral
• Therefore: biopsy of contralateral ovary is only indicated if macroscopically abnormal (except routine bilateral biopsy in dysgerminoma is not done either - just preserve the ovary)

When Surveillance is OK (NCCN 2025)

BEP Late Effects

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QUICK REFERENCE TABLE: ALL GCTs AT A GLANCE

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