Gestational Trophoblastic Disease

Gestational Trophoblastic Disease

Gestational Trophoblastic Disease

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GTD Spectrum - Trophoblast Tales

Gestational Trophoblastic Disease (GTD) encompasses a spectrum of disorders arising from abnormal proliferation of placental trophoblasts. It ranges from premalignant to malignant conditions.

WHO Classification:

  • Hydatidiform Mole
    • Complete Mole (CHM)
    • Partial Mole (PHM)
  • Invasive Mole
  • Choriocarcinoma
  • Placental Site Trophoblastic Tumor (PSTT)
  • Epithelioid Trophoblastic Tumor (ETT)

⭐ GTD originates from abnormal proliferation of placental trophoblast cells, the cells that normally develop into the placenta during pregnancy.

Molar Pregnancies - Grape Expectations

Hydatidiform Mole (HM), a key Gestational Trophoblastic Disease (GTD), includes Complete (CM) and Partial (PM) types.

FeatureComplete Mole (CM)Partial Mole (PM)
Karyotype46,XX (most) / XY; All paternal69,XXY/XXX; 2 Paternal, 1 Maternal
GenomeDiploid (Paternal only)Triploid
GrossDiffuse swelling; "bunch of grapes"Focal swelling; Fetus often present
Villous EdemaDiffuse, markedFocal, variable
Tropho. Prolif.Diffuse, circumferentialFocal, slight
Fetal TissuesAbsentOften present
hCG LevelsMarkedly ↑ (often > 100,000 mIU/mL)Moderately ↑
Uterine Size> dates (50%)< dates or normal
Theca Lutein CystsCommon (25-30%)Rare
ComplicationsHyperemesis, pre-eclampsia commonLess common
Ultrasound"Snowstorm"; No fetusCystic placenta; Fetus/sac may be present
Risk of GTN↑ (15-20%)↓ (1-5%)

Ultrasound of complete molar pregnancy

⭐ Complete mole typically has a 46,XX karyotype, with all chromosomes being of paternal origin.

Malignant GTD - When Trophoblasts Attack

Malignant Gestational Trophoblastic Diseases (GTD) represent a spectrum of aggressive trophoblastic proliferations.

  • Invasive Mole:
    • Invades myometrium.
    • Persistent ↑ hCG levels post-molar evacuation.
    • Chorionic villi present.
  • Choriocarcinoma:
    • Malignant proliferation of cytotrophoblasts & syncytiotrophoblasts.
    • NO chorionic villi.
    • Markedly ↑ hCG.
    • Early hematogenous spread (lungs, vagina).

    ⭐ Choriocarcinoma is highly aggressive and metastasizes early via bloodstream, most commonly to the lungs and vagina. Choriocarcinoma Histopathology

  • Placental Site Trophoblastic Tumor (PSTT):
    • Arises from intermediate trophoblasts at placental site.
    • Relatively ↓ hCG levels; hPL positive.
    • Late metastasis (lymphatic/hematogenous).
  • Epithelioid Trophoblastic Tumor (ETT):
    • Rare, nodular proliferation of intermediate trophoblasts.
    • Can mimic PSTT or squamous cell carcinoma.
    • Variable hCG levels.

GTD Detective & Doctor - Spot, Stage, Solve

Spot GTD:

  • Clinical: Vaginal bleeding, Uterine size > dates, Hyperemesis, Pre-eclampsia <20wks, Hyperthyroidism.

Key Investigations:

  • Serial quantitative β-hCG (crucial for monitoring).
  • Ultrasound (e.g., "snowstorm" for complete mole).

GTN Diagnosis (Post-Molar hCG Criteria):

  • Plateau: 4 values (±10%) over 3 wks (days 1, 7, 14, 21).
  • Rise: >10% for 3 values over 2 wks (days 1, 7, 14).
  • Persistence: Detectable β-hCG 6 months post-evacuation.
  • Histologic diagnosis (e.g., choriocarcinoma).

Stage & Solve GTN:

  • FIGO 2000 anatomic staging. Prognostic risk score based on:
    • Antecedent pregnancy, Interval from index pregnancy
    • Pre-treatment hCG level, Largest tumor size
    • Metastasis (site & number), Previous failed chemotherapy
  • Score: Low risk ≤6; High risk ≥7.

⭐ Serial β-hCG monitoring is the cornerstone for diagnosis of GTN, assessment of treatment response, and detection of relapse.

hCG regression curve after molar pregnancy evacuation

High‑Yield Points - ⚡ Biggest Takeaways

  • Complete moles: 46,XX (all paternal), no fetal parts, markedly ↑↑ hCG, higher choriocarcinoma risk.
  • Partial moles: Triploid (e.g., 69,XXY), fetal parts present, hCG less elevated.
  • hCG is the essential tumor marker for GTD diagnosis and follow-up.
  • Choriocarcinoma: Highly malignant, early metastasis (lungs), excellent chemotherapy response.
  • Invasive mole: Invades myometrium, persistent ↑ hCG post-evacuation.
  • PSTT: Rare, from intermediate trophoblasts, produces hPL, often chemoresistant.

Practice Questions: Gestational Trophoblastic Disease

Test your understanding with these related questions

What are the potential complications in subsequent pregnancies for a woman with a history of gestational trophoblastic disease?

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Flashcards: Gestational Trophoblastic Disease

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Most testicular germ-cell tumors originate from a precursor lesion called _____

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Most testicular germ-cell tumors originate from a precursor lesion called _____

germ-cell neoplasia in situ (GCNIS)

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