Yolk Sac Tumors

Slide 1 · Yolk Sac Tumors

Ovarian germ-cell pathology

Differentiation · Morphology · Differential diagnosis · Clinical correlation

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Classify yolk sac tumor within ovarian germ-cell neoplasia and explain its differentiation.

Interpret Schiller–Duval structures, hyaline droplets, and AFP-associated findings.

Contrast yolk sac tumor with important ovarian germ-cell tumor mimics.

Connect presentation, stage, and reported treatment outcomes to pathology.

Interpretation

Each objective is revisited in the morphologic and clinical cases.

Slide 3 · Core diagnostic signature

Lineage

Malignant ovarian germ-cell neoplasm with extraembryonic yolk-sac differentiation.

Tissue

Schiller–Duval bodies and characteristic hyaline droplets.

Protein

α-Fetoprotein production and AFP-positive material.

These findings are complementary; Neither clinical presentation nor an isolated stain replaces histologic interpretation.

Slide 4 · Definition: Malignant germ-cell differentiation

Yolk sac tumor is a malignant ovarian germ-cell tumor.

Historical synonym: Endodermal sinus tumor.

Cells show differentiation reminiscent of the extraembryonic yolk sac.

This developmental resemblance explains the naming and AFP production.

Interpretation

The lineage concept predicts characteristic architecture and protein expression.

Slide 5 · Position among ovarian tumors

Epithelial tumors

Separate ovarian neoplasm category; Do not confuse their risk profile with germ-cell tumors.

Germ-cell tumors

Include mature teratoma, dysgerminoma, yolk sac tumor and others.

Sex cord–stromal

Another category arising from stromal/sex-cord differentiation.

A category-level diagnosis precedes subclassification.

Slide 6 · Why ovarian germ-cell context matters

Germ-cell tumors account for 15%–20% of all ovarian tumors.

Most ovarian germ-cell tumors are benign mature cystic teratomas.

Malignant types concentrate in children and young adults.

A percentage for all germ-cell tumors must not be misread as YST prevalence.

Interpretation

Denominators determine how epidemiologic facts can be interpreted.

Slide 7 · Relative frequency of ovarian yolk sac tumor

The tumor is rare in the overall spectrum of ovarian tumors.

Robbins ranks it second among malignant ovarian germ-cell tumors.

Dysgerminoma is the most common malignant ovarian germ-cell tumor in the supplied section.

Relative rank does not establish a population incidence rate.

Interpretation

Rank and absolute incidence answer different questions.

Slide 8 · Developmental lineage explains the phenotype

Malignant germ cell

Germ-cell neoplasm arises in the ovary.

Yolk-sac direction

Neoplastic differentiation resembles extraembryonic tissue.

Tumor phenotype

AFP elaboration and endodermal-sinus-like architecture.

This is a conceptual lineage map, not a proven temporal sequence for an individual tumor.

Slide 9 · Germ-cell lines of differentiation

Dysgerminoma

Tumor resembles undifferentiated germ cells / oogonia.

Yolk sac tumor

Extraembryonic yolk-sac differentiation.

Choriocarcinoma

Extraembryonic placental / trophoblastic differentiation.

Teratoma

Somatic tissues representing germ-layer derivatives.

Lineage provides a disciplined basis for differential diagnosis.

Slide 10 · Meaning of extraembryonic differentiation

The normal yolk sac is an extraembryonic structure rather than an adult ovarian tissue.

YST recapitulates selected structural and secretory features of that developmental pathway.

The resemblance concerns tumor phenotype; It does not require an actual yolk sac.

A developmental analogy helps interpret AFP and glomeruloid morphology.

Interpretation

Do not describe a developmental analogy as direct lineage-tracing proof.

Slide 11 · Why the name endodermal sinus tumor persists

The historical name reflects resemblance to endodermal sinus structures.

Schiller–Duval bodies provide the classic glomerulus-like microscopic correlate.

“Yolk sac tumor” is the descriptive entity name used for this lecture.

Recognize both terms in pathology requests and prior records.

Interpretation

Terminologic equivalence prevents false separation of one entity into two.

Slide 12 · The AFP connection

Normal developmental program

The yolk sac can synthesize α-fetoprotein.

Neoplastic mimicry

Tumor cells reproduce this secretory differentiation.

Diagnostic observation

AFP may be demonstrated in tumor-associated material.

Biologic production is the source statement; The serum testing algorithm is not specified by the ovarian paragraph.

Slide 13 · Three different AFP statements

Protein production

Tumor cells elaborate AFP.

Tissue localization

AFP immunoperoxidase highlights many hyaline droplets.

Clinical marker

A serum measurement is a distinct laboratory result, requiring context.

Avoid conflating protein secretion, histologic staining, and a blood-test threshold.

Slide 14 · AFP: Interpret the level of evidence

Robbins explicitly documents AFP synthesis by yolk sac tumor cells.

The ovarian paragraph explicitly describes AFP-positive hyaline droplets.

It does not provide a diagnostic serum AFP cutoff or an assay sensitivity.

No threshold or false-negative rate should be inferred from the teaching source.

Interpretation

Source limitations are diagnostically important, not a reason to invent a threshold.

Slide 15 · Who usually presents?

Most patients are children or young females.

This contrasts with the older age distribution of many ovarian epithelial carcinomas.

Age influences clinical suspicion, not histologic definition.

An age-compatible presentation alone does not identify the tumor type.

Interpretation

Age is a pretest-context clue rather than a diagnostic criterion.

Slide 16 · Tumor growth and presentation

A rapidly enlarging pelvic mass is characteristic of the reported presentation.

Abdominal pain is a common accompanying complaint.

Tumor growth may bring a lesion to clinical attention before tissue diagnosis.

Clinical tempo establishes urgency but not histologic lineage.

Interpretation

Rapid growth warrants timely evaluation; Speed does not specify subtype.

Slide 17 · Ovarian laterality

The usual presentation as involving one ovary.

A unilateral mass is a compatible finding, not an exclusive condition.

Definitive interpretation still depends on the tissue findings.

Laterality and stage should not be assumed from a single imaging observation.

Interpretation

Do not convert “usually unilateral” into “always unilateral.”

Slide 18 · Clinical recognition: Assembling the clues

Clinical profile

Child or young female with abdominal pain.

Imaging / examination

Rapidly growing unilateral pelvic mass.

Pathology

Specific germ-cell differentiation establishes subtype.

This sequence represents reasoning, not a validated screening algorithm.

Slide 19 · Why symptoms do not specify the tumor

Abdominal pain and pelvic enlargement occur across several ovarian neoplasms.

Age and rapid growth narrow the clinical differential but do not prove YST.

Tissue architecture and tumor-associated products determine the pathologic direction.

Clinical and microscopic findings must be integrated without circular reasoning.

Interpretation

The question is “Which tumor explains these findings?”, not “Does pain prove YST?”.

Slide 20 · The diagnostic transition: From mass to morphology

Recognize a malignant ovarian germ-cell tumor as a differential category.

Assess architectural patterns and characteristic inclusions.

Correlate tissue morphology with a focused immunophenotype.

Consider alternative and mixed germ-cell differentiation before final classification.

Interpretation

Slide 21 · The fundamental histologic pattern

The classic Schiller–Duval body is glomerulus-like.

A central blood vessel is invested by tumor cells.

The cell-covered vessel projects into a space that is itself lined by tumor cells.

This architecture evokes, but is not identical to, a renal glomerulus.

Interpretation

The spatial relationship is more important than the name alone.

Slide 22 · Schiller–Duval body: Overall architecture

Central blood vessel

Inner tumor-cell layer

Outer tumor-lined space

Schematic only — native editable reconstruction; Do not treat as a histologic specimen.

Slide 23 · Component 1: Central blood vessel

Identify a vascular lumen in the center of the characteristic structure.

The capillary is the central core, not the surrounding empty space.

A glomeruloid impression depends on the correct spatial arrangement.

Vessel recognition anchors the rest of the structural interpretation.

Interpretation

Recognition is based on topology, not simply on a round pink focus.

Slide 24 · Schiller–Duval body: Locating the vascular core

Central blood vessel

Inner tumor-cell layer

Outer tumor-lined space

The central vessel is the innermost element; Tumor cells surround it.

Slide 25 · Component 2: Investing tumor cells

Neoplastic cells envelop the central vascular structure.

The tumor-cell sleeve distinguishes the central core from the adjacent space.

A vascular profile without surrounding neoplastic cells is insufficient.

Cell–vessel relationships must be assessed at adequate magnification.

Interpretation

Look for an epithelial cuff, not merely a free-standing vessel.

Slide 26 · Schiller–Duval body: Inner tumor-cell sleeve

Central blood vessel

Inner tumor-cell layer

Outer tumor-lined space

Inner tumor-cell layer surrounds the central vessel in the schematic.

Slide 27 · Component 3: Outer space and lining

The vascular core plus its tumor-cell envelope lies in a separate space.

Tumor cells also line the outer boundary of that space.

The two tumor-cell surfaces give the lesion an endodermal-sinus-like form.

The outer lining completes the defining three-dimensional relationship.

Interpretation

The classic description includes BOTH inner covering and outer lining.

Slide 28 · Schiller–Duval body: External lined space

Central blood vessel

Inner tumor-cell layer

Outer tumor-lined space

The external space is not a vessel lumen; It has a separate tumor-cell lining.

Slide 29 · Three components to name on H&E

Central capillary

Find the vessel inside the projecting central core.

Inner sleeve

Find tumor cells directly covering the vascular core.

Outer lining

Find tumor cells delineating the surrounding sinus-like space.

Check all three when using the name Schiller–Duval body.

Slide 30 · Why “glomeruloid” is an analogy

Both structures have a central vascular component surrounded by cells.

The tumor does not contain a normal renal nephron or functional filtration unit.

The analogy refers to appearance and organization, not kidney origin.

Use “glomerulus-like” as a morphology descriptor rather than a lineage claim.

Interpretation

Morphologic analogies facilitate recognition but cannot substitute for anatomy.

Slide 31 · Microscopic recognition workflow

Locate a vascular core

Do not label a simple gland as Schiller–Duval.

Trace inner investment

Identify tumor cells wrapping the vessel.

Trace the outer lining

Confirm a separate tumor-lined sinus-like space.

A short checklist is more reliable than relying on an impression of roundness.

Slide 32 · An absent Schiller–Duval body is not an exclusion

The ovarian Robbins paragraph identifies it as characteristic, not universally present.

The testicular yolk sac tumor section describes these bodies in approximately half of cases.

That testicular frequency must not be presented as an ovarian sensitivity estimate.

Broader architecture and tumor products remain important in incomplete sampling.

Interpretation

Cross-site observation does not establish an ovarian performance statistic.

Slide 33 · Architectural heterogeneity: Scope of the evidence

The ovarian excerpt specifically emphasizes Schiller–Duval bodies and hyaline droplets.

The companion testicular section describes a reticular pattern and several other patterns.

Major morphologic similarity between ovarian and testicular germ-cell tumors.

Cross-site examples aid pattern recognition but are not ovarian prevalence estimates.

Interpretation

Distinguish directly described ovarian features from cross-site morphology.

Slide 34 · Reticular or lace-like pattern

A reticular network in the testicular YST morphology section.

Spaces and branching cords produce a lace-like microscopic arrangement.

Tumor cells may be cuboidal, flattened, or spindled in that described pattern.

Pattern recognition does not remove the need to consider competing entities.

Interpretation

Cross-site teaching illustration, not a quantified ovarian growth-pattern frequency.

Slide 35 · Reading a reticular pattern

Network

Follow the interconnected tumor-cell strands.

Spaces

Identify variable-sized spaces between strands.

Context

Seek related yolk-sac differentiation findings.

Native schematic explains a text description; It is not a replacement micrograph.

Slide 36 · Papillary architecture can occur

Papillary structures in testicular yolk sac tumor.

Papillary growth alone is not a subtype-specific diagnosis.

Determine whether the central core resembles a Schiller–Duval body.

Use surrounding patterns and tumor-associated material for interpretation.

Interpretation

Distinguish a generic papilla from the characteristic glomeruloid construction.

Slide 37 · Solid cords can complicate recognition

The testicular YST section also describes solid tumor-cell cords.

A solid component may obscure distinctive sinus-like architecture.

An alternative pattern on one field should prompt search elsewhere in the lesion.

Avoid declaring or excluding differentiation solely from a single field.

Interpretation

A tumor may not display its hallmark architecture in every sampled area.

Slide 38 · Read morphology as a pattern set

Most characteristic

Schiller–Duval structure plus AFP-associated hyaline material.

Additional patterns

Reticular, papillary, and solid configurations described across gonadal YST.

Integrated reading

Interpret multiple regions and correlate with phenotype.

The last step is clinical-pathologic synthesis, not an additional textbook incidence claim.

Slide 39 · Hyaline droplets: A second major clue

Conspicuous intracellular and extracellular hyaline droplets.

Intracellular droplets lie in tumor-cell cytoplasm.

Extracellular droplets lie outside identifiable tumor-cell boundaries.

The droplets provide diagnostic information beyond tumor architecture.

Interpretation

Describe location before describing immunophenotypic significance.

Slide 40 · Intracellular versus extracellular droplets

Intracellular

Hyaline material is contained within the neoplastic cell.

Extracellular

Hyaline material lies among the tumor cells.

Both locations are explicitly described in the ovarian YST source.

Slide 41 · What is special about the hyaline material?

The droplets are conspicuous and hyaline on routine morphology.

Many of these droplets stain for α-fetoprotein by immunoperoxidase.

The staining behavior is compatible with secretory yolk-sac differentiation.

A droplet becomes most meaningful when read together with tumor architecture.

Interpretation

The text says “most” droplets stain; It does not claim 100% sensitivity.

Slide 42 · Morphology-to-protein correlation

Cellular phenotype

Yolk-sac-like tumor differentiation.

Protein product

α-Fetoprotein elaborated by neoplastic cells.

Microscopic correlate

AFP-positive hyaline droplets in and around cells.

The chain links directly stated observations; It does not measure diagnostic accuracy.

Slide 43 · Immunoperoxidase: What is actually demonstrated?

The ovarian section demonstrates AFP immunostaining of many hyaline droplets.

An immunostain localizes an antigen in tissue sections.

A positive field must be interpreted in the correct cell and tissue context.

No stand-alone AFP immunohistochemistry cutoff is provided in this source.

Interpretation

Do not equate localization of protein with proof of an entire tumor type.

Slide 44 · Cross-site YST immunophenotype

Robbins’ testicular YST description notes expression of AFP.

It additionally names glypican-3 and cytokeratin.

These observations are background for gonadal germ-cell differentiation.

The ovarian excerpt does not supply a validated multistain decision rule.

Interpretation

State the source location when teaching beyond the ovarian paragraph.

Slide 45 · Marker roles must not be conflated

Observation

Robbins source supports

Not established here

Tumor-cell AFP production

Ovarian YST elaborates AFP

Serum positivity threshold

AFP-positive droplets

Ovarian tissue immunoperoxidase

Whole-tumor sensitivity

Glypican-3, cytokeratin

Testicular YST expression

Ovarian-specific diagnostic accuracy

RUNX3 / GATA-4

Possible pathogenetic roles

Routine clinical test criteria

Slide 46 · RUNX3: An epigenetic observation

The ovarian Robbins text mentions RUNX3 gene hypermethylation.

This change is proposed as potentially involved in YST pathogenesis.

Hypermethylation is not the same event as a DNA sequence mutation.

The supplied source does not describe an approved RUNX3 diagnostic assay.

Interpretation

Preserve the uncertainty expressed in “may be involved.”

Slide 47 · GATA-4: An expression observation

GATA-4 overexpression is mentioned as possibly involved in tumor pathogenesis.

Overexpression and RUNX3 hypermethylation describe different molecular phenomena.

The mechanistic connection is not demonstrated in the short ovarian excerpt.

Do not portray GATA-4 as a validated predictive marker on this basis.

Interpretation

Candidate mechanistic involvement is not a clinical biomarker indication.

Slide 48 · Pathogenesis: Observation versus implication

Source observation

Supported language

Unsupported leap

RUNX3 hypermethylation

May participate in pathogenesis

Necessary initiating event

GATA-4 overexpression

May participate in pathogenesis

Sufficient cause or validated driver

AFP secretion

Characteristic differentiation product

A unique molecular alteration

Slide 49 · Differential diagnosis: The basic branches

Dysgerminoma

Primitive germ-cell morphology; No characteristic Schiller–Duval structure.

Teratoma

Multiple differentiated or immature tissue elements.

Choriocarcinoma

Trophoblastic differentiation and hCG production.

Mixed germ-cell tumor

Two or more histologically recognizable components.

Use lineage, architecture and product together.

Slide 50 · YST versus dysgerminoma

Feature

Yolk sac tumor

Dysgerminoma

Lineage

Extraembryonic yolk sac

Primitive germ-cell / oogonial

Signature architecture

Schiller–Duval body

Sheets / cords of large clear cells

Background

Hyaline droplets

Lymphocyte-rich fibrous septa

Source marker emphasis

AFP

OCT3/4, NANOG, KIT

Slide 51 · Why dysgerminoma is a practical mimic

Both entities are malignant ovarian germ-cell tumors, often in younger patients.

Dysgerminoma commonly shows large clear cells in sheets or cords.

Fibrous septa and lymphocytes support the dysgerminoma direction.

Schiller–Duval architecture and AFP-bearing hyaline material support YST.

Interpretation

The age bracket is a shared clinical setting, not a discriminating stain.

Slide 52 · YST versus immature teratoma

Feature

Yolk sac tumor

Immature teratoma

Differentiation

Extraembryonic yolk-sac line

Immature fetal / embryonal tissues

Characteristic tissue

Schiller–Duval body / droplets

Immature neuroepithelium

Grading in Robbins

Stage-based outcomes stated

Grade reflects immature neuroepithelium

Pitfall

Misread mixed components

Miss a superimposed YST element

Slide 53 · YST versus ovarian choriocarcinoma

Feature

Yolk sac tumor

Choriocarcinoma

Extraembryonic lineage

Yolk sac

Trophoblast / placenta

Secretory product

AFP

Chorionic gonadotropin

Signature morphology

Schiller–Duval body / droplets

Placental-type trophoblastic morphology

Clinical behavior in text

Chemotherapy-responsive survival figures

Often hematogenously metastatic

Slide 54 · Mixed germ-cell tumors: Why to sample carefully

Robbins explicitly lists mixed germ-cell tumors with YST among possible components.

Different regions may represent different germ-cell differentiation pathways.

The diagnostic label should represent the full sampled lesion.

A single classic focus need not describe all other components.

Interpretation

The need for multi-region evaluation follows from explicitly recognized tumor mixtures.

Slide 55 · Embryonal carcinoma: Cross-site context

Embryonal carcinoma as highly malignant primitive embryonal tissue.

The testicular section describes marked atypia and alveolar or tubular growth.

Testicular embryonal carcinoma expresses OCT3/4 and SALL4 in the text.

A mixed ovarian germ-cell neoplasm may contain more than one differentiated pattern.

Interpretation

Cross-site descriptions are context, not an ovarian-specific test-performance estimate.

Slide 56 · A defensible diagnostic reasoning sequence

Identify category

Malignant ovarian germ-cell tumor is considered.

Read architecture

Search for Schiller–Duval structures and hyaline droplets.

Correlate phenotype

Use AFP localization plus assessment of other components.

Conclude with context

Integrate the clinical and pathologic picture.

Educational sequence; Local laboratory protocols and formal criteria are outside the source excerpt.

Slide 57 · Pitfall: A plausible age does not prove YST

Several ovarian germ-cell tumors occur in children and young adults.

“Young patient” is shared context across important alternatives.

The mass must be characterized histologically.

Subtype-specific architecture remains central to differential diagnosis.

Interpretation

Avoid anchoring on age alone.

Slide 58 · Pitfall: AFP cannot carry every diagnostic decision

A secretory tumor product is strong supportive evidence when compatible with tissue findings.

Protein production and serum assay interpretation are distinct concepts.

No specificity, cut-off, or negative predictive value is supplied in the ovarian excerpt.

A mixed tumor may need recognition of additional differentiation beyond YST.

Interpretation

Never derive assay-performance numbers from a textbook phenotype statement.

Slide 59 · Outcome data reported by Robbins

Stage I–II

Five-year survival greater than 95% with combination chemotherapy.

Stage III

Five-year survival 70% with combination chemotherapy.

Stage IV

Five-year survival 50% with combination chemotherapy.

Numbers are presented exactly as the source reports; Stage-system edition and cohort are not identified in the excerpt.

Slide 60 · Early-stage prognosis in the source

Five-year survival above 95% for stages I–II with combination chemotherapy.

The greater-than sign is deliberate: The source gives a lower bound, not 95.0%.

This favorable figure is not a claim of zero relapse or universal cure.

Patient-specific prognosis requires more information than a textbook stage group.

Interpretation

Avoid converting a population-level figure into an individual prediction.

Slide 61 · Stage III: Prognosis remains distinct

Robbins gives a 70% five-year survival figure for stage III disease.

This is lower than the grouped stage I–II estimate.

The source does not give a stage III subcategory breakdown.

No confidence interval or patient-count denominator is provided in the excerpt.

Interpretation

Preserve both the reported estimate and its reporting limitations.

Slide 62 · Stage IV: Reported five-year survival

The corresponding stage IV figure is 50%.

This indicates a worse outcome than the earlier stage groups.

The text does not describe the statistical uncertainty of that estimate.

A stage value without cohort definition should not be treated as an individualized forecast.

Interpretation

Do not infer specific metastatic sites or treatment lines from the percentage alone.

Slide 63 · Reading the three reported survival figures

Stage group

Five-year survival in Robbins

Technical caution

I–II

>95%

Strict lower-bound notation

III

70%

No interval provided

IV

50%

No interval provided

Slide 64 · Chemotherapy and the pathology message

Combination chemotherapy is explicitly associated with the stated survival outcomes.

The excerpt does not specify a regimen, drug dosing, or treatment sequence.

Do not interpret the figures as an untreated natural-history series.

The pathology lecture should emphasize correct entity recognition and disease extent.

Interpretation

Regimen choice requires separate current oncology guidance and patient context.

Slide 65 · Survival data: Boundaries of interpretation

Robbins gives stage-group survival estimates, not Kaplan–Meier data.

Stage I and II are reported together rather than as separate outcomes.

No numerator, denominator, median follow-up, or confidence interval appears in the source.

Do not manufacture a survival curve or stage-by-stage raw data from these summaries.

Interpretation

A textual percentage is not a substitute for source survival-time data.

Slide 66 · Case 1: Rapidly growing ovarian mass

CLINICOPATHOLOGIC REASONING

A 16-year-old has abdominal pain and a rapidly enlarging unilateral ovarian mass. Tumor sections show a central vessel coated by malignant cells projecting into another tumor-lined space.

Identify the characteristic structure and state the most likely differentiation.

Slide 67 · Case 1: Morphologic answer

The described vascular and tumor-cell relationship is a Schiller–Duval body.

The defining feature is the central vessel plus inner and outer tumor-cell layers.

In the stated setting this is characteristic of yolk sac tumor.

AFP production and hyaline material would provide related corroboration.

Interpretation

The stem is hypothetical and supplies enough morphology for the teaching inference.

Slide 68 · Case 2: Protein-rich hyaline material

CLINICOPATHOLOGIC REASONING

A malignant ovarian germ-cell tumor shows abundant hyaline droplets both within cells and outside cells. Immunoperoxidase stains most sampled droplets for α-fetoprotein.

What lineage does this support, and what does the stain NOT establish?

Slide 69 · Case 2: Interpret the stain at the right level

AFP-positive hyaline droplets support yolk-sac differentiation.

The statement refers to tissue antigen localization in sampled material.

It does not specify a serum AFP cutoff.

It does not remove the need to inspect architecture and exclude mixed components.

Interpretation

Report precisely what the stain showed, not more.

Slide 70 · Case 3: Separating germ-cell subtypes

CLINICOPATHOLOGIC REASONING

A 21-year-old has an ovarian germ-cell malignancy with sheets of large clear cells and lymphocyte-rich fibrous stroma. No Schiller–Duval structure is described.

Which comparator diagnosis is better supported by these findings?

Slide 71 · Case 3: Architectural discrimination

Dysgerminoma is favored by sheets of large clear cells and lymphocyte-rich stroma.

Those findings are specifically described in the Robbins dysgerminoma section.

Lack of a described Schiller–Duval body is not by itself a validated YST exclusion.

Classification depends on the total morphology and appropriate assessment.

Interpretation

The case tests positive distinguishing features instead of a purely absent finding.

Slide 72 · High-yield synthesis

YST is malignant ovarian germ-cell differentiation toward the extraembryonic yolk sac.

Schiller–Duval architecture is a central vessel invested by cells in a tumor-lined space.

Hyaline droplets and AFP expression provide complementary phenotype clues.

Stage-dependent outcomes with combination chemotherapy.

Interpretation

Integrate lineage, architecture, protein, and stage in that order.

Slide 73 · References and source boundaries

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th edition (2026).

Primary ovarian YST paragraph: Chapter 22, printed pp. 930–931.

Adjacent ovarian germ-cell comparisons: Chapter 22, pp. 929–932.

Cross-site reticular and immunophenotypic descriptions: Chapter 21, testicular yolk sac tumor section.

No original Chapter 22 PDF or authentic histology images were supplied for independent figure verification.

Interpretation

Full per-slide source mapping and caveats are retained in speaker notes.