Placental site trophoblastic tumor

Introduction to placental site trophoblastic tumor Placental in situ trophoblastic tumor (PSTT) is rare, more common in women in the reproductive period, patients often due to amenorrhea, miscarriage, hydatidiform mole or irregular vaginal bleeding after full-term pregnancy. PSTT is a tumor formed by excessive proliferation of intermediate trophoblast cells after pregnancy. The tumor cells are similar to the cells in the placenta implantation site. Immunohistochemistry shows that hPL (placental prolactin) positive cells are more than hCG positive cells, and placental site trophoblastic tumors. The patient has a good prognosis and a few can metastasize. Clinically rare, most of them are benign clinically, generally do not metastasize, and the prognosis is good. PSTT is a rare tumor originating from intermediate trophoblasts. It has been called trophoblastic pseudotumor, atypical choriocarcinoma, chorionic epithelial disease, syncytial tumor or atypical chorionic epithelioma. In 1981, Scully et al named it PSTT. And with hydatidiform mole, invasive hydatidiform mole, choriocarcinoma as a fourth trophoblastic tumor. Most of the disease is benign, about 10% to 15% due to metastatic disease called malignant PSTT, the mortality rate is 20%. basic knowledge The proportion of illness: 0.0015% Susceptible population: women in childbearing period Mode of infection: non-infectious Complications: peritonitis sepsis nephrotic syndrome splenomegaly spider mites

Placental site trophoblastic tumor etiology

Congenital factors (90%):

A special type of trophoblastic tumor derived from the placenta implant site. A trophoblastic tumor, also known as "trophoblastic disease," refers to a tumor formed by the malignant transformation of the embryonic trophoblasts. It was first divided into two types, one benign called "hydatidiform mole" and the other malignant called "chorioep ithelioma".

Pathological examination

From the naked eye, the tumor is located in the placenta planting site, which is nodular, brownish yellow, and the tumor of the cut surface invades the myometrium. The boundary with the surrounding tissue is unclear, and the degree of infiltration of the muscle layer is different. In a few cases, the tumor can penetrate the full layer of the uterus. . Generally no significant bleeding.

Microscopically, during normal pregnancy, the function of intermediate trophoblast cells is to immobilize the embryo body on the surface of the muscle layer. When the intermediate trophoblast cells are tumor proliferative, the infiltration is similar to the normal nourishing leaf epithelium at the placenta attachment site, and is still located in a typical site where the nourishing leaf epithelium grows vigorously. The cell morphology is relatively simple, mostly mononuclear, rich in cytoplasm, clear border, light red, and larger than cytotrophoblast cells. A small number of cells are multinucleated or binuclear, and the tumor cells are arranged in a single, strip-like, flaky or island-like manner between the myometrial cells. Generally no necrosis and fluff. Unlike chorionic epithelial carcinoma, the placental site trophoblastic tumor consists of a single proliferating placental intermediate trophoblast cell, which is composed of two types of cells. Immunohistochemical staining of most intermediate trophoblastic cells was positive for Human placental lactoge (HPL); only a small number of cells were positive for HCG. In a few cases, tumor cells may be abnormal, cells are dense and dense, mitotic figures are more common, accompanied by extensive necrosis, showing malignant histology.

Pathological features

Giant examination: the uterus is enlarged, and the tumor can be nodular (1cm to 10cm in diameter), polypoid (1cm to 1.5cm in diameter) protruding into the uterine cavity, or a clear mass in the uterine wall, or diffusely infiltrating the uterine wall. There is no clear boundary for the thickening of the palace wall. The cut surface is purple-red or tan, soft and granular, and can be accompanied by micro-hemorrhage. Some tumors can infiltrate through the muscle layer and spread to the serosa or spread to the broad ligaments and attachments.

Microscopic examination: PSTT consists of intermediate trophoblast cells, mostly round and polygonal, a few are fusiform, cytoplasm rich, basophilic or translucent, the nucleus is mostly single round, the nuclear membrane and nucleolus are clear, and the tumor cells are arranged. The pieces and strips separate the smooth muscle fibers without causing extensive musculature damage; the invading blood vessels replace the vascular endothelial cells by tumor cells and/or fibrous tissue, maintaining the relative integrity of their morphology, and the intravascular tumor thrombus is not common. The pathological changes of metastases are mostly the same as those of the primary lesions. Metastases can be found in the lungs, liver, brain, vagina, abdominal cavity, kidney, stomach, spleen, and lymph nodes.

Immunohistochemistry: Epithelial-derived markers EMA and CK were positive, and most of them were strong positives above ++; Vim and Act of primitive mesenchymal cells and myocyte markers were negative, supporting PSTT as a non- Mesenchymal non-sarcoma-like tumors. HPL is positive and mostly strong positives above ++, while HCG is only positive for individual cells, confirming that a large number of mononuclear cells in this tumor are similar to intermediate trophoblasts in the second trimester of pregnancy, rich in HPL, while HCG is Very little or absent.

Placental site trophoblastic tumor prevention

Follow-up after treatment. Because the patient's serum and urine HCG measurements are often not high, the significance of clinical presentation and imaging follow-up is very important.

Placental site trophoblastic tumor complications Complications, peritonitis, sepsis, nephrotic syndrome, splenomegaly

1 difficult to control major bleeding; 2 severe infection caused by peritonitis or sepsis; 3 uterine perforation with hemorrhage, infection and visceral injury; 4 acute pulmonary embolization (acute pulmonary embolization), a large number of small grape beads invading the pulmonary artery, can cause rapid death; 5 acute pulmonary right heart failure (acuteo Dnpulmonale).

Some placental sites of trophoblastic tumors may be associated with nephrotic syndrome, polycythemia, splenomegaly or spider mites.

Placental site trophoblastic tumor symptoms common symptoms amenorrhea menstrual flow more vaginal irregular bleeding

Occurred at the reproductive age, can be secondary to full-term birth, abortion and hydatidiform mole, but the latter is relatively rare, occasionally combined with a live pregnancy. Symptoms often show irregular vaginal bleeding or menorrhagia after menopause. The main signs are that the uniformity of the uterus is increased or irregularly increased. Only a few cases have extrauterine metastasis. The affected parts mainly include the lung, vagina, brain, liver, kidney and pelvic and para-aortic lymph nodes. Once metastasis occurs, the prognosis is poor. Symptoms and signs:

1, medical history: generally secondary to full-term production, abortion or hydatidiform mole, the disease can also be combined with pregnancy.

2, symptoms: mainly manifested as irregular vaginal bleeding or menorrhagia, sometimes amenorrhea, often accompanied by anemia, edema. A few cases with metastatic symptoms as the first symptom. Later in the metastasis, the lungs are more common, and the brain and liver are less.

3, gynecological examination: the uterus can increase the size of 8-16 weeks of pregnancy, showing irregular or even increase.

Examination of trophoblastic tumors in the placenta

According to the emptying or abortion of the hydatidiform mole, full-term delivery, vaginal bleeding and/or metastases after ectopic pregnancy and their corresponding symptoms and signs combined with the auxiliary examination, considering the possibility of the disease, and finally diagnosed by histological diagnosis. Common auxiliary checks are as follows:

1, blood -HCG determination: most negative or slightly elevated. Only 1/3-1/2 patients are elevated, and -HCG levels are usually <3000 IU/L.

2, blood HPL: mildly elevated or negative.

3, ultrasound examination: B-type ultrasound showed the hypoechoic area in the uterine muscle wall, color Doppler ultrasound can be seen with diastolic components dominant low-impedance, blood flow rich tumor image.

4, pathological examination: generally according to the curettage specimen can make a histological diagnosis of placental site trophoblastic tumor, clinically often diagnosed by curettage.

Diagnosis and differentiation of trophoblastic tumors in placenta

diagnosis

The clinical manifestations and imaging examination of PSTT are not specific. The diagnosis needs to be combined with the auxiliary examination to determine the pathology. In addition to curettage and hysterectomy, there are also hysteroscopy and laparoscopy to detect the abnormal distribution of blood vessels in the uterus, whether there is perforation in the intrauterine tumor, and parallel biopsy.

Differential diagnosis

(1) choriocarcinoma: tumor cells are mainly cell and syncytiotrophoblasts, hemorrhagic necrosis is significant, serum HCG is abnormally increased, immunohistochemical HCG is strongly positive, and HPL is negative. The tumor cells of PSTT are single intermediate trophoblast cells, with less or less hemorrhagic necrosis, and immunohistochemical HPL-strong positive, HCG negative or weak positive.

(2) Epithelial trophoblastic tumor: The tumor is derived from the intermediate type of trophoblastic cells of the villus type. The tumor cells are small, often forming nests or strips, growing in the form of inflated nodules, immunohistochemically HPL and melanin. Adhesion factors are usually locally positive, while PSTT is diffusely positive.

(3) Placental nodules: This tumor is a benign lesion with small size and clear boundary. It has nothing to do with recent pregnancy. It is usually found occasionally during curettage, cervical biopsy or other reasons for removal of the uterus. Histology can be seen in a wide range of transparent changes. Mixed with intermediate trophoblast cells of the villus model, and no trophoblastic infiltrating muscle layer, occasional or no nuclear fission, immunohistochemical HPL and melanin adhesion factors are usually locally positive or negative, contrary to PSTT.

(4) Supernormal placental reaction: This disease has a large number of intermediate trophoblast cells in the placenta bed, which is difficult to distinguish from the diagnostic specimens of PSTT. HCG identification is needed. The serum HCG value of abnormal responders drops to normal after several weeks, while PSTT Continue to not fall or rise.

(5) uterine leiomyosarcoma: This tumor is easily confused with PSTT fusiform intermediate trophoblastoma cells, but leiomyosarcoma muscle-derived antibodies are positive and HPL is negative.

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