Gestational trophoblastic neoplasia (GTN) is a group of rare tumors characterized by abnormal trophoblastic proliferation following pregnancy including invasive moles, choriocarcinomas, and intermediate trophoblastic tumors (ITT). Although the treatment and follow-up of GTN has been heterogeneous, globally the emergence of expert networks has helped to harmonize its management.
We provide an overview of the current knowledge, diagnosis, and management strategies in GTN and discuss innovative therapeutic options under investigation. While chemotherapy has been the historical backbone of GTN treatment, promising drugs such as immune checkpoint inhibitors targeting the PD-1/PD-L1 pathway and anti-angiogenic tyrosine kinase inhibitors are currently being investigated remodeling the therapeutical landscape of trophoblastic tumors.
Chemotherapy regimens for GTN have potential long-term effects on fertility and quality of life, making innovative and less toxic therapeutic approaches necessary. Immune checkpoint inhibitors have shown promise in reversing immune tolerance in GTN and have been evaluated in several trials. However, immunotherapy is associated with rare but life-threatening adverse events and evidence of immune-related infertility in mice, highlighting the need for further research and careful consideration of its use. Innovative biomarkers could help personalize GTN treatments and reduce chemotherapy burden in some patients.

Placental site trophoblastic tumor (PSTT), also known as atypical choriocarcinoma, syncytioma, chorioepitheliosis or trophoblastic pseudotumor, is a rare gestational trophoblastic disease (0.25-5% of all trophoblastic tumors) and it is composed by neoplastic proliferation of intermediate trophoblasts at placental implantation site. It consists of aggregates or sheets of large, polyhedral to round, predominantly mononucleated cells with a characteristic vascular and myometrial invasion. Main differential diagnoses are gestational choriocarcinoma (GC) and epitelioid trophoblastic tumor (ETT). We present a case of PSTT in a 25-year-old woman. Neoplastic cells showed moderate/high nuclear pleomorphism, abundant amphophilic, eosinophilic and clear cytoplasm, numerous mitotic figures (10 mitoses/10 HPF), and myometrial invasion. Other features are necrosis, vascular invasion with replacement of myometrial vessels by tumor cells and hemorrhage. The patient showed typical low serum β-hCG levels and high serum humane placental lactogen (hPL) levels.

Objective: Mixed gestational trophoblastic neoplasia (GTN) is a rare occurrence that refers to the coexistence of choriocarcinoma and/or placental site trophoblastic tumor and/or epithelioid trophoblastic tumor. The diagnosis and management of mixed GTN are challenging. We investigated the clinicopathological characteristics, diagnoses, treatments, and outcomes of patients with mixed GTN. Materials and Methods: The medical records and pathological sections of 16 patients with mixed GTN who were treated at Peking Union Medical College Hospital and The Second Xiangya Hospital of Central South University between January 2012 and December 2018 were reviewed. Results: Pretreatment serum human chorionic gonadotropin (hCG) levels ranged from 180 to 625,024 IU/L, and were >10,000 IU/L in 14 of the 16 patients, none of whom were diagnosed correctly at initial presentation. Two patients were diagnosed with choriocarcinoma coexisting with intermediate trophoblastic tumor (ITT) through dilation and curettage (D&C) before treatment. Another 5 patients were histologically confirmed to have placental site trophoblastic tumor (PSTT) by D&C but final pathological findings showed mixed PSTT and choriocarcinoma at subsequent hysterectomy. Seven post-chemotherapy patients with an initial clinical diagnosis of choriocarcinoma underwent surgery because of chemoresistance and their pathological findings revealed coexisting ITT. The remaining 2 patients were found to have choriocarcinoma coexisting with ITT following cervical biopsy and pulmonary lobectomy. All patients received chemotherapy: 14 underwent surgery combined with chemotherapy and 2 received chemotherapy alone to preserve fertility. Other than 1 patient who died of disease progression, 15 patients (93.8%) achieved complete remission (CR) after treatment, although 5 (33.3%) relapsed. Of these 5 patients with relapse, 3 achieved CR after additional treatment, 1 was receiving an immune checkpoint inhibitor, and 1 was lost to follow-up after refusing further therapy. Conclusion: Mixed GTN is difficult to diagnose on initial presentation. Overlap of the ITT component should be considered in refractory chemoresistant choriocarcinoma. Coexistence of choriocarcinoma should be suspected in ITT patients with high hCG levels. Surgery combined with chemotherapy is optimal treatment for choriocarcinoma mixed with ITT.

OBJECTIVE: To identify important prognostic factors and optimized treatment strategies through the analysis of the clinical and pathological characteristics of placental site trophoblastic tumor.
METHODS: 108 patients with PSTT registered in two GTD centers or in six tertiary hospitals in China were analyzed retrospectively between the years 1998 and 2013. The computerized database of clinical and pathological reports was reviewed on this patient group. The data were subsequently analyzed retrospectively using SPSS software.
RESULTS: Among 3581 patients with GTNs treated in GTD centers or in the tertiary hospitals between 1998 and 2013, 108 cases were histologically confirmed PSTT (3%). Only seven deaths and eleven relapse cases were observed. All seven of the deaths were disease related, due to chemotherapy-resistant or relapsed. 23 patients who received fertility preservation treatment did not experience poor outcome or high risk of relapse. In 71 patients with International Federation of Gynecology and Obstetrics (FIGO) stage I disease, the use of adjuvant chemotherapy following surgery (n=49) or not (n=22) made no significant difference in relapse rate (P=0.303) or survival (P=0.782). Univariate analysis revealed the interval between antecedent pregnancy and onset of PSTT, stage, prognosis score, and necrosis as significant predictors of poor survival but only stage remained significant on multivariate analysis.
CONCLUSIONS: Patients with FIGO stage IV disease demonstrate the most critical risk indicator of PSTT in the current study. Preservation of fertility is considered in highly-selected patients with localized tumor; and surgery without chemotherapy is recommended as first line treatment for patients with stage I who are at low-risk.

We present a case of a gravida 1 para 1 woman, who presented with an 11-month history of amenorrhea after cesarean delivery. The patient was taking birth control pills at the time of presentation. She was observed with a slight elevation of serum β-hCG level, an enlarged heterogeneous uterus and hematometra. A biopsy was performed, and the patient was diagnosed with placental site trophoblastic tumor; the patient then underwent surgery. Placental site trophoblastic tumor is the rarest form of gestational trophoblastic disease, derived from intermediate trophoblast cells. It does not have a pathognomonic appearance; therefore, correlation with medical history, as well as results of laboratory tests and pathological analysis is mandatory. It is a relatively chemoresistant tumor, posing considerable therapeutic challenges; patients with localized disease are managed with surgery and those with metastatic disease require additional chemotherapy. Herein, we review the main features of this entity and top differential diagnosis, as the rarity of this tumor is associated with imaging and pathological pitfalls, reinforcing the need for further experience in this field.

Gestational trophoblastic neoplasms are a group of fetal trophoblastic tumors including choriocarcinomas, epithelioid trophoblastic tumors (ETTs), and placental site trophoblastic tumors (PSTTs). Mixed gestational trophoblastic neoplasms are extremely rare. The existence of mixed gestational trophoblastic neoplasms that were composed of choriocarcinoma and/or PSTT and/or ETT was also reported. Herein, we present a case of uterine mixed gestational trophoblastic neoplasm which is ETT admixed with PSTT, and reviewed 9 cases of mixed gestational trophoblastic neoplasms reported in English literature available. The most common combination was a choriocarcinoma admixed with an ETT and/or PSTT. Mixed gestational trophoblastic neoplasms present in women of reproductive age and rare in postmenopausal, Abnormal vaginal bleeding is the most common presenting symptom, serum β-HCG levels are elevated, mostly below 2500 mIU/ml, the tumor was limited to uterus in 7 cases, the rest of 3 with pulmonary metastases at the time of diagnosis. Mixed gestational trophoblastic neoplasms have more similar clinical features with intermediate trophoblastic tumors (ITTs). Total hysterectomy with lymph node dissection is recommended treatment for mixed gestational trophoblastic neoplasms, and chemotherapy should be used in patients with metastatic disease and with nonmetastatic disease who have adverse prognostic factors.

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•Histologic morphology is frequently equivocal for PSTTs.•Histology combined with immunohistochemical staining was necessary to make the diagnosis.•PSTT confined to the uterus was successfully treated with surgery alone.