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PA29.{5,10} | Gestational Trophoblastic Disease & Female Genital Morphology — SDL Guide (Part 3)

Ovarian Tumors — Epithelial Tumors: Serous and Mucinous

Ovarian tumors are classified by their cell of origin: surface epithelium (~70%), germ cells (~20%), sex-cord stromal (~8%), and metastatic (~5–10%). The practical exam requires recognition of each major type.

Serous tumors (most common epithelial subtype):

Benign serous cystadenoma: Unilocular or multilocular thin-walled cyst, smooth inner surface, watery serous fluid. Micro: single layer of ciliated tubal-type epithelium, no atypia, no stromal invasion.

Serous borderline tumor: Papillary projections into cyst lumen; micro: stratified epithelium, mild atypia, no destructive stromal invasion (< 5 mm microinvasion tolerated).

High-grade serous carcinoma (HGSC): Bilateral in ~70%; solid and cystic; papillary, micropapillary, or cribriform architecture; marked nuclear atypia, aberrant p53, TP53 mutation; slit-like spaces; psammoma bodies (laminated calcifications).

Side-by-side H&E-style comparison of benign serous cystadenoma with a single ciliated epithelial lining and high-grade serous carcinoma with papillary fronds, atypia, psammoma bodies, and stromal invasion. — **Panel A:** Benign serous cystadenoma showing cyst lumen, single layer of ciliated tubal-type epithelium, uniform basal nuclei, ciliated cells, fibrous cyst wall, and absence of stromal invasion.. **Panel B:** High-grade serous carcinoma showing complex papillary architecture, malignant stratified epithelium, nuclear atypia, mitotic figures, psammoma body, and stromal invasion..

Mucinous tumors:

Mucinous cystadenoma: Multilocular cyst filled with thick mucinous fluid; micro: tall columnar cells with basal nuclei and apical mucin (resembling endocervical or intestinal epithelium); no atypia.

Mucinous carcinoma: Infiltrative glands with stromal invasion; goblet cells may be present (intestinal type); distinguish from appendiceal mucinous carcinoma metastasis (bilateral mucinous = suspect metastasis).

Diagram of mucinous cystadenoma showing a large multilocular ovarian cyst with gelatinous mucin, thin septa, and compressed ovarian stroma. — **Panel A:** Gross opened ovarian mucinous cystadenoma showing multilocular cyst, locules, gelatinous mucin, thin cyst septa, and residual ovarian stroma.. **Panel B:** Magnified cut-surface detail showing mucin-filled locules, thin septa, and clear gelatinous mucin.. **Panel C:** Simplified structural map showing compressed ovarian stroma surrounding multiple mucin-filled cystic cavities..

H&E-style teaching diagram of ovarian mucinous cystadenoma showing tall mucinous columnar cells with basal nuclei and comparison with serous cystadenoma epithelium. — **Panel A:** H&E 10× overview showing cyst lumen, folded mucinous epithelial lining, tall mucinous columnar cells, basal nuclei, intracytoplasmic mucin, and fibrous cyst wall.. **Panel B:** High-power cellular inset showing mucin vacuoles, tall columnar epithelium, basal oval nuclei, and absence of stromal invasion.. **Panel C:** Comparison of mucinous cystadenoma epithelium with serous cystadenoma epithelium, highlighting tall mucin-filled cells versus ciliated tubal-type cells..

Ovarian Tumors — Germ Cell, Sex-Cord Stromal, and Metastatic Tumors

Mature cystic teratoma (dermoid cyst) — most common ovarian germ-cell tumor:

Gross: Cystic, contains hair, sebaceous material, teeth, bone (ectodermal elements dominate); cut surface shows a Rokitansky protuberance (solid mural nodule from which teeth/hair arise)
Micro: All three germ layers — squamous epithelium with hair follicles, sebaceous glands (ectoderm); intestinal/respiratory epithelium (endoderm); cartilage, smooth muscle (mesoderm)

Opened mature cystic teratoma showing hair, sebaceous content, tooth or bone, and a labeled mural nodule with magnified ectodermal derivatives. — **Panel A:** Opened mature cystic teratoma with cyst wall, hair, sebaceous content, tooth/bone fragment, Rokitansky protuberance, and mural nodule.. **Panel B:** Simplified ovary showing dermoid cyst location and origin of the mural nodule from the cyst wall.. **Panel C:** Magnified mural nodule contents showing ectodermal derivatives including hair shaft, sebaceous gland, keratin debris, and calcified tooth/bone..

Dysgerminoma (counterpart of testicular seminoma):

Most common malignant ovarian germ-cell tumor in young women
Gross: Solid, fleshy, cream-colored tumor
Micro: Large polygonal cells with clear glycogen-rich cytoplasm and central prominent nuclei, arranged in sheets and nests separated by fibrous septa with lymphocytic infiltrate
Marker: LDH and placental-like alkaline phosphatase (PLAP); hCG elevated only if syncytiotrophoblastic elements present

Illustrated H&E histology of dysgerminoma showing sheets of large clear tumor cells separated by fibrous septa containing lymphocytes. — **Panel A:** H&E section of dysgerminoma at 10× showing large clear tumor cells, central nuclei, fibrous septum, and lymphocytes. **Bottom legend strip:** Color key for tumor cells, fibrous septum, and lymphocytes.

Granulosa cell tumor (sex-cord stromal, most common):

Gross: Solid and cystic, yellow-tinged (luteinization); may have hemorrhagic foci (danger: torsion or rupture → hemoperitoneum)
Micro: Call-Exner bodies — rosette-like arrangements of granulosa cells around a central space containing eosinophilic material (resembling primordial follicles); 'coffee-bean' (longitudinally grooved) nuclei
Endocrine: Produces estrogen → endometrial hyperplasia, precocious puberty (in girls), postmenopausal bleeding in older women
Marker: Inhibin (serum and IHC)

Three-panel H&E histology diagram of ovarian granulosa cell tumor showing Call-Exner bodies and coffee-bean nuclear grooves. — **Panel A:** Low-power H&E 20× field showing granulosa tumor cells, multiple Call-Exner bodies, central eosinophilic material, and pale tumor stroma.. **Panel B:** Magnified Call-Exner body showing rosette arrangement of granulosa cells around central eosinophilic hyaline material.. **Panel C:** High-power granulosa tumor cell detail showing oval coffee-bean nuclei with longitudinal nuclear grooves and scant cytoplasm..

Krukenberg tumor (metastatic):

Definition: Bilateral ovarian metastasis with signet-ring cells distending with mucin in a cellular fibromatous stroma
Primary: Classically gastric adenocarcinoma (diffuse type); also colorectal, appendix, breast
Gross: Bilateral, solid or solid-cystic; ovarian architecture partially preserved
Micro: Signet-ring cells (nucleus pushed to periphery by mucin vacuole) in a hypercellular fibromatous ovarian stroma

Diagram of H&E Krukenberg tumor showing signet-ring cells with mucin vacuoles and peripheral nuclei within hypercellular fibromatous ovarian stroma. — **Panel A:** H&E 20x overview showing signet-ring cells, peripheral nuclei, mucin vacuoles, and hypercellular fibromatous ovarian stroma. **Panel B:** Magnified signet-ring cell showing mucin vacuole, peripheral compressed nucleus, and thin rim of cytoplasm. **Panel C:** Diagnostic infiltration pattern showing metastatic mucin-secreting signet-ring cells within dense fibromatous ovarian stroma.

Master Recognition Table — Female Genital Tract Practical Quick-Reference

Use this table as your bench-side reference. For each entity, the examiner expects you to name the gross appearance, the key microscopic feature, and the clinical-diagnostic clue.

Lesion	Gross	Key Micro Feature	Clinical / Practical Clue
Chronic cervicitis	Reddened, erosive ectocervix; nabothian cysts	Lymphoplasmacytic stroma, squamous metaplasia	Common; nabothian cysts = mucus retention
Endometriosis	Chocolate cyst (ovary); powder-burn peritoneum	Endometrial glands + stroma + hemosiderin macrophages	Triad mandatory for diagnosis
Simple hyperplasia	Thickened endometrium	Dilated cystic glands, abundant stroma, no atypia	Low malignant risk; exogenous estrogen history
Atypical hyperplasia	Polypoid thickening	Crowded glands, nuclear atypia, prominent nucleoli	25–30% risk carcinoma; precancerous
Endometrioid carcinoma	Polypoid fundal mass	Invasive glands, desmoplastic stroma, graded by solid %	Postmenopausal bleeding; Grade 1–3
Leiomyoma	Firm, white, whorled nodule	Uniform spindle cells, intersecting fascicles, no atypia	Most common pelvic tumor; multiple
Leiomyosarcoma	Soft, fleshy, hemorrhagic	Atypia + ≥10 mit/10HPF + coagulative necrosis	De novo; not from fibroid
Complete mole	Grape-like vesicular villi, no fetus	All hydropic villi, circumferential trophoblastic hyperplasia	Very high hCG; 46,XX androgenetic
Partial mole	Focal vesicular + fetal parts	Two villi populations, scalloped villi, trophoblastic inclusions	Triploid 69,XXY; lower hCG
Choriocarcinoma	Hemorrhagic, necrotic uterine mass	Biphasic cyto + syncytiotrophoblast; NO villi	Markedly elevated hCG; MTX-curable
Serous cystadenoma	Unilocular, smooth, watery	Ciliated single-layer tubal epithelium	Benign; most common benign epithelial
HGSC ovary	Solid-cystic, bilateral	Papillary architecture, marked atypia, psammoma bodies	Most lethal; TP53; serous carcinoma
Mucinous cystadenoma	Multilocular, gelatinous	Tall columnar cells, basal nuclei, apical mucin	Unilateral; can be massive
Mature teratoma	Cyst with hair/sebum/teeth	All 3 germ layers; squamous lining dominant	Most common germ-cell tumor; benign
Dysgerminoma	Solid, fleshy, cream	Clear cells in sheets; fibrous septa with lymphocytes	Young women; LDH marker
Granulosa cell tumor	Yellow, solid-cystic	Call-Exner bodies; coffee-bean nuclei	Estrogen-secreting; inhibin marker
Krukenberg tumor	Bilateral, solid	Signet-ring cells in cellular fibromatous stroma	GI primary (stomach); bilateral metastasis

CLINICAL PEARL

The bilateral ovary rule: When you see bilateral ovarian tumors, think metastasis first until proven otherwise. Primary ovarian tumors are bilateral in ~70% of high-grade serous carcinomas (and the bilaterality is part of their spread pattern), but a mucinous, signet-ring-cell, or solid bilateral ovarian tumor should trigger a search for a GI primary. The classic exam question pairs bilateral ovarian solid tumors with a gastric history — that is Krukenberg.

SELF-CHECK

On a practical slide you see: an ovarian tumor with polygonal cells arranged in sheets, clear glycogen-rich cytoplasm, centrally placed nuclei with prominent nucleoli, and fibrous septa infiltrated by lymphocytes. The most likely tumor is:

A. Granulosa cell tumor

B. Dysgerminoma

C. High-grade serous carcinoma

D. Krukenberg tumor

Reveal Answer

Answer: B. Dysgerminoma

This is the classic histological description of dysgerminoma — large polygonal cells with clear cytoplasm (glycogen), prominent nuclei, arranged in sheets separated by fibrous septa with a lymphocytic infiltrate. Granulosa cell tumors have Call-Exner bodies and coffee-bean grooved nuclei. High-grade serous carcinoma shows papillary architecture, psammoma bodies, and marked atypia without the lymphocytic septa or clear-cell quality. Krukenberg shows signet-ring cells in a fibromatous stroma.