Introduction:
While a healthy trophoblast's malignant behavior is tightly regulated, in GTD, the regulatory mechanisms may malfunction, leading to highly invasive vascular and metastatic tumors. The term "gestational trophoblastic neoplasia" (GTN) refers to the malignant conditions associated with gestational diabetes mellitus (GTD), which include choriocarcinoma, epithelioid trophoblastic tumor (ETT), invasive mole, and placental site trophoblastic tumor (PSTT). If treatment for these conditions is delayed or inadequate, they may spread and become lethal.
What Is Gestational Trophoblastic Neoplasia?
Given the variability in statistics on the total number of pregnancies and trophoblastic illness, it is challenging to determine the true incidence of GTN. Roughly half of GTN instances occur following a molar pregnancy; the other 25 % may occur following a miscarriage, abortion, or ectopic pregnancy; the last 25 % may occur following a term or preterm pregnancy. A collection of uncommon tumors that appear in the early stages of pregnancy is collectively referred to as gestational trophoblastic disease (GTD).
After conception, a woman's body surrounds the freshly fertilized egg or embryo with a layer of cells known as the trophoblast to prepare it for pregnancy. The embryo uses the trophoblast's assistance to attach to the uterine wall. Additionally, a sizable portion of the tissue that makes up the placenta, the organ that nourishes a developing child, comprises these cells. Tumors arise as a result of aberrant trophoblast cell alterations in GTD.
What Is Nonmetastatic Gestational Trophoblastic Disease?
The term "nonmetastatic gestational trophoblastic disease" is a rare form that refers to a group of similar placental tumors in humans. Nearly all of these individuals can be cured with a range of regimens with acceptable toxicity, thanks to the development of efficient chemotherapy. In certain cases, hysterectomy can help save lives by reducing the quantity of chemotherapy needed to achieve remission and by saving patients who have not responded to initial treatment. Most patients can maintain their ability to bear children, and many have healthy pregnancies following treatment.
What Are the Types of Gestational Trophoblastic Neoplasia?
Different forms of gestational trophoblastic neoplasia include:
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Choriocarcinoma: This malignant growth develops inside the uterus of a pregnant woman. Typically, molar pregnancies result in growths that develop into malignant choriocarcinomas. Rarely, tissue left in the uterus following an abortion, miscarriage, or the delivery of a healthy infant can develop into choriocarcinomas.
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Placental-Site Trophoblastic Tumor (PTT): The placenta joins to the uterine wall at this location, which is incredibly unusual, as a slowly developing tumor forms there. Many times, placental-site trophoblastic malignancies go undetected for years following a full-term pregnancy.
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Epithelioid Trophoblastic Tumor (ETT): Despite its great rarity, the course of an epithelioid trophoblastic tumor is similar to that of a placental-site trophoblastic tumor. Usually, the tumor produces deep tissue invasion in the form of distinct nodules or cystic hemorrhagic masses. There are visible fistulas, ulcerations, necrosis, and bleeding. ETT is characterized by homogeneous, medium-sized tumor cells arranged in nests, ropes, or massive sheets that exhibit nodular, expandable development.
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Invasive Mole: Trophoblast cells create an atypical mass that expands into the uterine muscle layer.
What Is the Pathophysiology of Gestational Trophoblastic Neoplasia?
GTN originates from the placenta in all cases. While PSTTs and ETTs originate from intermediate trophoblasts, choriocarcinomas and hydatidiform moles (HMs) come from villous trophoblasts. Abnormal budding, folded villous blood vessels, trophoblastic hyperplasia, and stromal karyorrhectic detritus are all present in first-trimester complete HMs. On the other hand, patchy villous hydrops, distributed irregularly shaped villi, patchy trophoblastic hyperplasia, and trophoblastic pseudo-inclusions are characteristics of early partial HMs.
A molar pregnancy can seldom coexist with a regular pregnancy. Ultrasound is typically used to make the diagnosis. 40 % to 60 % of spontaneous abortion cases end in live births despite the considerable risk involved. In a solitary molar pregnancy, the risk is 15 % to 20 %; in a coexisting molar and normal pregnancy, the risk is 27 % to 46 %. If there are no problems, negative results from genetic testing, and normal ultrasound findings, the pregnancy can continue.
How Is Gestational Trophoblastic Neoplasia Diagnosed?
The main diagnostic method for GTN is ultrasound. An ultrasound of a whole mole typically reveals the existence of theca lutein ovarian cysts and a uterus filled with a heterogeneous mass, also known as the "snowstorm" sign, along with no fetal development. Sadly, there is no evidence of these findings throughout the first trimester. It is generally not possible to diagnose postmolar GTN patients based on symptoms or distinctive ultrasonography findings; instead, a link between tumor burden and hCG levels is required. MRI (magnetic resonance imaging) is usually only needed in the standard assessment of GTN if there are unusual presentations, recurrences, ETTs, or PSTTs.
Conclusion
The malignant type of prenatal trophoblastic illness is called gestational trophoblastic neoplasia (GTN). When treating non-metastatic GTN, Methotrexate (MTX) or Actinomycin D produces remarkable results. All cancer specialists must work together to manage GTN. To effectively diagnose GTN and identify disease staging, healthcare providers must collaborate in the scheduling and coordinating diagnostic testing, including hCG (human chorionic gonadotropin) measures, imaging examinations, and histopathological evaluations. The multidisciplinary team then creates customized treatment programs for the particular GTN subtype and stage. Referrals to trophoblastic disease centers may be required in particularly difficult instances.
