UNASSIGNED: Gestational trophoblastic tumors are very rare neoplasms. We determined the distinctive morphological, immunohistochemical, and clinical features of placental site trophoblastic tumors (PSTT) and epithelioid trophoblastic tumors (ETT) in our cohort.
UNASSIGNED: Nine cases of PSTT and four cases of ETT were retrieved from the archives. Histomorphologic, immunohistochemical, and clinical features were noted. A molecular study was performed on one PSTT and one ETT case using next-generation sequencing.
UNASSIGNED: While the nodular pattern, geographic necrosis, and extracellular eosinophilic globules were peculiar to ETTs, vessel wall affinity, marked pleomorphism, intranuclear pseudoinclusion, spindle tumor cell, and vacuolar degeneration were more specific for PSTTs in our series. An immunohistochemical panel of p63, hPL, and CD146 were helpful for the exact typing of the tumor. p63 positivity supports the ETT and diffuse staining of hPL and CD146 supports the PSTT diagnosis. Three of the patients with metastatic disease (lung and brain metastasis) except one have a high mitotic count (12 and 8) and a long interval between (8 and 10 years) antecedent pregnancy and diagnosis. While KIT and TP53 mutations were observed only in PSTT, amino acid changes in KDR, APC, and SMAD4 genes were detected both in the ETT and PSTT cases.
UNASSIGNED: In the prediction of metastasis, the long intervals between antecedent pregnancy and diagnosis, deep myometrial invasion, mitotic count, and Ki67 proliferation index were involved rather than other histomorphological parameters, but none of the parameters is an absolute predictor of the metastasis.

UNASSIGNED: There is no consensus for the management of epithelioid trophoblastic tumor (ETT) up to date.
UNASSIGNED: ETT is the rarest form of gestational trophoblastic neplasia (GTN). Our goal was to assess the outcomes and explore the prognostic factors of patients with ETT through this multicenter retrospective analysis and to devise a risk-adapted approach to clinical management.
UNASSIGNED: A total of 31 patients were validated as ETT pathologically between January 2004 and June 2021 from three tertiary hospitals. We retrospectively analyzed the characteristics, treatments, outcomes, and prognostic factors.
UNASSIGNED: Eight patients experienced a recurrence, and 6 patients died of ETT, resulting in a mortality rate of 19.4%. Five patients with stage I disease had a fertility-preserving treatment. Among them, one patient had a full-term delivery, whereas a 23-year-old patient who declined a hysterectomy died of a recurrent disease. Eight patients of extrauterine ETT with isolated pulmonary lesion were at a young age at diagnosis (median: 30.5 vs. 41, p = 0.003) and had a smaller tumor size (median: 2.4 vs. 4.8 cm, p = 0.003) compared with other patients who had a metastatic disease, and none of them died. The multivariate analyses showed that the number of metastases ≥3 [hazard ratio (HR), 28.16, p = 0.003] was the only significant predictor associated with adverse overall survival, while the number of metastases ≥3 (HR 9.59, p = 0.005) and chemotherapy alone (HR 16.42, p = 0.001) were associated with adverse recurrence-free survival. Patients in stage I or with number of metastases <3 had a favorable prognosis, whereas the prognosis of patients whose number of metastases ≥3 remains poor.
UNASSIGNED: Chemotherapy alone is insufficient for patients with ETT. Surgical procedures are the mainstay of management for ETT patients. Combined surgery and multi-agent chemotherapy are recommended for patients with metastatic disease and localized disease with persistently positive human chorionic gonadotrophin levels after surgery. The number of metastases at ≥3 is the most critical risk factor for ETT.

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.

Epithelioid Trophoblastic Tumor (ETT) is an extremely rare form of Gestational Trophoblastic Neoplasia (GTN). Knowledge on prognostic factors and optimal management is limited. We identified prognostic factors, optimal treatment, and outcome from the world\'s largest case series of patients with ETT.
Patients were selected from the international Placental Site Trophoblastic Tumor (PSTT) and ETT database. Fifty-four patients diagnosed with ETT or mixed PSTT/ETT between 2001 and 2016 were included. Cox regression analysis was used to identify prognostic factors for overall survival (OS).
Forty-five patients with ETT and 9 patients with PSTT/ETT were included. Thirty-six patients had FIGO stage I and 18 had stages II-IV disease. Patients were treated with surgery (n = 23), chemotherapy (n = 6), or a combination of surgery and chemotherapy (n = 25). In total, 39 patients survived, including 22 patients with complete sustained hCG remission for at least 1 year. Patients treated with surgery as first line treatment had early-stage disease and all survived. Most patients treated with chemotherapy with or without surgery had FIGO stages II-IV disease (55%). They underwent multiple lines of chemotherapy. Eleven of them did not survive. Interval since antecedent pregnancy and FIGO stage were prognostic factors of OS (p = 0.012; p = 0.023 respectively).
Advanced-stage disease and an interval of ≥48 months since the antecedent pregnancy are poor prognostic factors of ETT. Surgery seems adequate for early-stage disease with a shorter interval. Advanced-stage disease requires a combination of treatment modalities. Because of its rarity, ETT should be treated in a centre with experience in GTN.