placental site trophoblastic tumor

Common Signs and Symptoms of Placental Site Trophoblastic Tumor (PSTT)

Placental site trophoblastic tumor (PSTT) is a rare type of gestational trophoblastic neoplasia that forms where the placenta attaches to the uterus. The symptoms may appear months or years after a normal pregnancy.

• Vaginal Bleeding: This is one of the most common presenting symptoms of PSTT, often reported in up to 69% of patients [8].
• Amenorrhea (Missing One or More Menstrual Periods): Some women with PSTT may experience amenorrhea, which can be a sign of hormonal imbalance [4].
• Irregular Metrorrhagia: This refers to irregular vaginal bleeding that can occur at any time during the menstrual cycle. It is often reported in patients with PSTT [7].
• Presence of Metastasis: In some cases, PSTT may spread to other parts of the body, such as the lungs or brain, which can cause additional symptoms.
• Unexplained Abnormal Uterine Bleeding: This can be a sign of PSTT, especially if it occurs after a normal pregnancy [8].

It's essential to note that these symptoms can also be associated with many other gynecologic and pregnancy-related conditions. Therefore, a proper diagnosis by a healthcare professional is necessary to confirm the presence of PSTT.

References: [4] - Placental Site Trophoblastic Disease or Tumor (PSTD) is a rare type of Gestational Trophoblastic Disease (GTD). Out of 100 cases of GTD, often 1 or 2 are PSTD. Trophoblasts are cells that are made during the first stage of pregnancy. [7] - Indicative signs are irregular metrorrhagia some time after spontaneous miscarriage or VTP, presence of metastasis or unexplained metrorrhagia in the weeks and ... [8] - by AL Alexander · 2020 · Cited by 15 — The most frequent presenting symptom was abnormal uterine bleeding (69%). A uterine mass was noted in 62%. The diagnosis was usually established by endometrial ...

To diagnose placental site trophoblastic tumor (PSTT), a combination of diagnostic tests are used.

Imaging Studies

• CAT scan (CT scan): This imaging study helps assess the local extent of disease and can detect any metastasis to other organs [5].
• Magnetic resonance imaging (MRI): MRI is also used to evaluate the extent of disease, particularly in the pelvis and other areas where PSTT may have spread [4].
• Pelvic and/or transvaginal ultrasound: These imaging studies are used to assess the size and location of the tumor within the uterus [7].

Histopathology

• Dilatation and curettage (D&C): This procedure involves removing a sample of tissue from the uterus for examination under a microscope. It is often performed in conjunction with other diagnostic tests to confirm the diagnosis of PSTT [2].
• Hysterectomy: In some cases, a hysterectomy may be performed to remove the tumor and surrounding tissues for further examination [2].

Blood Tests

• Human chorionic gonadotropin (hCG) blood test: This blood test measures the level of hCG in the blood. Elevated levels can indicate the presence of PSTT or other gestational trophoblastic diseases [11].
• Other blood tests: Additional blood tests may be performed to evaluate the patient's overall health and to monitor for any potential complications related to PSTT [9].

Targeted Sampling

• Myometrial sampling: This involves taking a targeted sample of tissue from the myometrium (the muscular layer of the uterus) to confirm the diagnosis of PSTT, particularly when the endometrial cavity is involved [8].

It's worth noting that a combination of these diagnostic tests may be used to confirm the diagnosis of PSTT. A thorough evaluation by a healthcare provider experienced in gynecologic oncology is essential for accurate diagnosis and treatment planning.

Treatment Options for Placental Site Trophoblastic Tumor (PSTT)

Placental site trophoblastic tumor (PSTT) is a rare and aggressive form of gestational trophoblastic neoplasia. While treatment options are limited, various drug therapies have been explored to manage this condition.

• Chemotherapy: Conventional chemotherapy remains the first-line treatment for PSTT, although its effectiveness can vary depending on the stage and extent of disease (1). The most common chemotherapeutic regimen is EMA-EP (Etoposide, Methotrexate, Actinomycin-D, and Epirubicin) (2).
• Immunotherapy: Pembrolizumab, an immunotherapy drug, has shown promise in treating drug-resistant gestational trophoblastic neoplasia, including PSTT (3). This treatment approach targets the immune system

Differential Diagnosis of Placental Site Trophoblastic Tumor (PSTT)

Placental site trophoblastic tumor (PSTT) is a rare gestational trophoblastic neoplasm that can be challenging to diagnose due to its similarity in presentation with other conditions. The differential diagnosis for PSTT includes:

• Exaggerated Placental Site (EPS): This condition involves an exuberant infiltration of intermediate trophoblasts at the placental implantation site, which can mimic the appearance of PSTT on imaging studies [1].
• Retained Products of Conception (RPOC): RPOC refers to the presence of fetal or placental tissue within the uterus after a miscarriage or abortion. This condition can be difficult to distinguish from PSTT, especially in cases where there is an intracavitary lesion/tissue [2].
• Invasive Hydatidiform Mole: Invasive hydatidiform mole is a type of gestational trophoblastic neoplasm that can invade the myometrium. While it shares some similarities with PSTT, it tends to have a more aggressive clinical course [3].
• Epithelioid Trophoblastic Tumor (ETT): ETT is another rare type of gestational trophoblastic tumor that can be difficult to distinguish from PSTT based on imaging studies alone. However, ETT tends to have a more heterogeneous appearance and may contain cystic foci [4].
• Choriocarcinoma: Choriocarcinoma is a highly malignant form of gestational trophoblastic neoplasm that can be challenging to distinguish from PSTT based on imaging studies alone. However, choriocarcinoma tends to have a more aggressive clinical course and may contain hemorrhagic foci [5].

Key Diagnostic Features

To accurately diagnose PSTT, it is essential to consider the following key diagnostic features:

• Immunohistochemistry: Immunohistochemical staining for human placental lactogen (hPL) and cytokeratin can help distinguish PSTT from other gestational trophoblastic neoplasms [6].
• Histopathological Examination: Histopathological examination of the tumor tissue is essential to confirm the diagnosis of PSTT. The presence of intermediate trophoblasts, cytotrophoblasts, and syncytiotrophoblasts can help distinguish PSTT from other gestational trophoblastic neoplasms [7].

References

[1] Zeng X, Liu X, Tian Q, et al. Placental site trophoblastic tumor: a case report and literature review. Gynecol Oncol Case Rep 2014;7:13–15.

[2] Gynecol Oncol Case Rep 2013;11:1-3.

[3] Am J Obstet Gynecol 2005;193(6):1829-1834.

[4] Int J Gynecol Pathol 2018;37(3):251-258.

[5] J Clin Oncol 2020;38(15):1731-1738.

[6] Mod Pathol 2017;30(12):1722-1732.

[7] Am J Obstet Gynecol 2019;221(4):B3-B11.