Gestational trophoblastic neoplasia (GTN) is primarily treated with chemotherapy, but surgery plays a key role at different steps in disease management, including initial diagnosis, primary therapy, and salvage options. Initial diagnosis is usually made by electric or manual vacuum aspiration for molar pregancy or uterine curettage for other forms of GTN. Excisional procedures of localized disease, whether second curettage or hysterectomy, can obviate chemotherapy, but patients still require monitoring for relapse. Resection remains a useful adjunct for either the management of isolated foci of chemoresistant disease or the management of bleeding complications.

OBJECTIVE: Placental site trophoblastic tumor (PSTT) is a rare form of gestational trophoblastic neoplasm with few previous imaging case reports. We report multiparametric MRI findings in four cases of PSTT with special emphasis on the \"pseudo-myometrial thinning\" underlying the tumor.
METHODS: We reviewed multiparametric MRI and pathologic findings in four cases of PSTT from four institutions. Signal intensity, enhancement pattern, margins, and location of the tumors were evaluated, and myometrial thickness underlying the tumor and normal myometrial thickness contralateral to the tumor were measured on MRI. The myometrial thickness underlying the tumor was also measured in the resected specimen and compared with the myometrial thickness measured on MRI using the Friedman test.
RESULTS: All tumors showed heterogeneous signal intensity on T1-weighted imaging, T2-weighted imaging (T2WI), and diffusion-weighted imaging. Three of the four tumors had a hypervascular area on dynamic contrast-enhanced (DCE) MRI. A hypointense rim on T2WI and DCE-MRI was seen in all tumors. All tumors protruded into the uterine cavity to varying degrees and extended into the myometrium close to the serosa. The myometrial thickness underlying the tumor measured on MRI (median thickness, 1.2 mm) was significantly thinner than that measured on pathology (median thickness, 9.5 mm) and normal myometrial thickness contralateral to the tumor on MRI (median thickness, 10.3 mm) (P = 0.02), and there was no significant difference between the latter two.
CONCLUSIONS: The thickness of the myometrium underlying the tumor on MRI was approximately one tenth of the thickness on pathology. Thus, the tumors appeared to have almost transmural invasion even when pathologically located within the superficial myometrium. This \"pseudo-thinning\" of the underlying myometrium and the hypointense rim on MRI could be caused by focal compression of the myometrium by the tumor, possibly due to the fragility of the myometrium at the placental site.

BACKGROUND: Epithelioid Trophoblastic Tumor (ETT) and Placental Site Trophoblastic Tumor (PSTT) are two of the rarest GTNs that share certain features at diagnosis and management. Atypical Placental Site Nodule (APSN) is a relatively new entity considered as a premalignant lesion.
OBJECTIVE: The aim of this review was to summarize the main characteristics of each of these entities, their diagnostic features, and their treatment\'s standard of care including fertility-sparing treatments.
RESULTS: This study provides a thorough review of ETT, PSTT, and APSN.
CONCLUSIONS: The reader will gain an insight view of these rare tumors arising from the intermediate trophoblast.

We previously described a series of cases which characterize a distinct group of primary ovarian placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) as a non-gestational set consistent with germ cell type/origin. Here we report a new case of ovarian non-gestational PSTT. The patient was a 13 year-old young female admitted for a spontaneous pneumothorax of the left lung. The pathology of lung wedge excision specimen demonstrated metastatic PSTT and ovarian biopsy showed atypical intermediate trophoblastic proliferation which was found to be PSTT in the subsequent salpingo-oophorectomy specimen. In the ovary, the tumor was composed of singly dispersed or small clusters of predominantly mononuclear cells and rare multinucleated cells extensively infiltrating the ovarian parenchyma, tubal mucosa, and paraovarian/paratubal soft tissue. A minor component of mature cystic teratoma (less than 5% of total tumor volume) was present. Immunohistochemically, the neoplastic cells of main tumor were diffusely immunoreactive for hPL, Gata3 and AE1/AE3, and had only rare hCG-positive or p63-positive cells. The morphology and immunohistochemical results support a PSTT. Molecular genotyping revealed an identical genotype pattern between the normal lung tissue and the metastatic PSTT, indicating its non-gestational nature of germ cell type/origin. This case represents the first case of such tumor with distant (lung) metastasis. This case also provides further evidence to support our recommendation that primary ovarian non-gestational intermediate trophoblastic tumors of germ cell type/origin, including PSTT and ETT, should be formally recognized in classification systems.

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.

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.

To analyze the methods, feasibility, efficiency, and fertility outcomes of fertility-sparing treatment for patients with placental site trophoblastic tumor (PSTT).
Clinical data of patients diagnosed with PSTT between April 1998 and April 2020 from Peking Union Medical College Hospital (PUMCH) were retrospectively collected. The clinical features, treatment, and outcomes of patients received fertility-sparing treatment were analyzed and compared with patients suffered hysterectomy.
In total, 126 patients were included in the study and 29 of them received fertility-sparing treatment. Besides significantly younger age and lower proportion of antecedent term delivery were seen in fertility-sparing group than hysterectomy group, no significant differences were observed in stage, serum β-hCG level, or interval from antecedent pregnancy between the two groups. Conservative surgery was selected individualized and none of them suffered salvage hysterectomy. Patients with clinical or pathological high-risk factors received adjuvant chemotherapy, yet the fertility-sparing treatment did not significantly lengthen chemotherapy duration. All patients in fertility-sparing group achieved complete remission without relapse after 36 to 176 months of follow-up and had sixteen healthy term delivery more than one year after the treatment.
Fertility-sparing treatment for PSTT can be considered for young patients with localized uterine lesions who strongly desire to preserve their fertility potential. With individualized conservative surgery and selected adjuvant chemotherapy, fertility-sparing treatment will not influence the risk of relapse or overall survival and patients will achieve favorable pregnancy and live birth outcomes.

Gestational trophoblastic diseases (GTD) encompass a spectrum of rare pre-malignant and malignant entities originating from trophoblastic tissue. This updated review will highlight important radiological features, pathology and classification, and provide insight into the clinical management of these uncommon disorders. There is a wide geographic variation with the incidence of hydatidiform mole varying between 0.57 and 2 per 1000 pregnancies. The use of ultrasound (US) in the management of early pregnancy symptoms and complications has positively impacted the earlier detection of these diseases and resulted in diminished morbidity. Additional imaging modalities are reserved for problem solving or assessment of pulmonary manifestations of molar pregnancy. Having an awareness of their pleomorphic sonographic presentation and additional pathology that can mimic GTD is critical to avoiding pitfalls. Histologic and molecular analysis further aids in differential diagnosis. Gestational trophoblastic neoplasia (GTN) is inclusive of all malignant GTDs, and arises after 20% of molar pregnancies but can also be seen with non-molar gestations. Biochemical monitoring with human chorionic gonadotrophin is imperative for ongoing monitoring and surveillance and allows early detection of this entity. Doppler US is used for confirmation of diagnosis with magnetic resonance imaging (MRI) reserved for problem solving or assessment of myometrial invasion. This is of heightened relevance in patients undergoing surgical management. Cross sectional imaging is reserved for patients in the setting of GTN for the purposes of staging, prognostication and in the setting of recurrent disease. This may require a combination of computed tomography, MRI and positron emission tomography. Doppler US can provide insight into chemotherapeutic response/predict resistance in patients with GTN. As our understanding of these disorders evolves, there has been maturation in management options with a shift from traditional chemotherapy to innovative immunotherapy, particularly in the setting of resistant or high-risk disease.

Pathologic diagnosis of gestational trophoblastic disease (GTD)-hydatidiform moles and gestational trophoblastic neoplasms-underwent a major shift in the past decade from morphology-based recognition to precise molecular genetic classification of entities, which also allows for prognostic stratification of molar gestations. This article highlights these recent advances and their integration into the routine pathology practice. The traditional gross and histomorphologic features of each entity are also reviewed with special focus on differential diagnoses and their clinical implications.

Gestational trophoblastic disease (GTD) is a heterogeneous group of lesions that are characterized by the abnormal proliferation of the trophoblast. Morphology, behavior and clinical significance vary tremendously and range from benign, non-neoplastic lesions that cause sometimes dysfunctional uterine bleeding to aggressive, highly, malignant tumors. The recently updated 2020 World Health Organization (WHO) Classification of Female Genital Tumors divides GTD in molar pregnancies/ hydatidiform moles, gestational trophoblastic neoplasms, tumor-like lesions and abnormal (nonmolar) villous lesions. In this article we review the typical clinical presentations of GTDs, their histopathologic features, contributing immunohistochemical stains and current diagnostic criteria. We discuss novel insights in the proposed pathogenesis, newly proposed entities and advances in ancillary diagnostic techniques and their relevance to the histopathologic diagnosis of GTD. Additionally we briefly review current treatment options, prognosis and prognostic factors of GTDs.