Ovarian non-gestational placental site trophoblastic tumor with lung metastasis: further evidence for a distinct category of trophoblastic neoplasm.

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.

Reconsideration of the Diagnostic Criteria for an Atypical Placental Site Nodule Comparing Typical Placental Site Nodule of the Uterus: A Report of Two Cases.

Placental site nodules (PSNs) are non-neoplastic remnants of chorionic-type intermediate trophoblastic cells from a previous gestation that form a well-defined single nodule or multiple nodules in the uterine and extrauterine sites. As the cases of PSNs transformed into gestational trophoblastic tumors were described in the literature, "atypical placental site nodules" (APSNs) have been considered as putative transitional lesions between PSNs and gestational trophoblastic tumors. Although histologic criteria and cutoff point of Ki-67 proliferation index for differentiating an APSN from a typical PSN have not been clearly defined, nodules larger than 5 mm with increased cellularity, a corded or nested appearance, marked nuclear atypia, increased mitotic activity, and an increased Ki-67 proliferation index (>5% or >8%) of intermediate trophoblastic cells seem to be accepted as diagnostic criteria for APSNs. However, some of the criteria, including lesion size and histologic features of the trophoblastic cells in the nodule are not only subjective but have features inherent of the intermediate trophoblastic cells of the fetal membrane and a typical PSN. We thought that it is not reasonable to consider them as diagnostic features of APSNs, if not associated with cellular proliferation. We present 2 cases of incidentally identified PSNs that were larger than 10 mm in size with a corded or nested arrangement of trophoblastic cells, which could have been categorized as APSNs according to the currently proposed criteria to discuss whether the currently proposed diagnostic criteria for APSNs are appropriate.

Molecular Analyses of Chorionic-Type Intermediate Trophoblastic Lesions: Atypical Placental Site Nodules are Closer to Placental Site Nodules Than Epithelioid Trophoblastic Tumors.

Gestational trophoblastic diseases derived from the chorionic-type intermediate trophoblast include benign placental site nodule (PSN) and malignant epithelioid trophoblastic tumor (ETT). Among PSNs, the World Health Organization classification introduced a new entity named atypical placental site nodule (APSN), corresponding to an ETT precursor, for which diagnostic criteria remain unclear, leading to a risk of overdiagnosis and difficulties in patient management. We retrospectively studied 8 PSNs, 7 APSNs, and 8 ETTs to better characterize this new entity and performed immunohistochemical analysis (p63, human placental lactogen, Cyclin E, and Ki67), transcriptional analysis using the NanoString method to quantify the expression of 760 genes involved in the main tumorigenesis pathways, and RNA sequencing to identify fusion transcripts. The immunohistochemical analysis did not reveal any significant difference in Cyclin E expression among the 3 groups (P = .476), whereas the Ki67 index was significantly (P < .001) higher in ETT samples than in APSN and PSN samples. None of the APSN samples harbored the LPCAT1::TERT fusion transcripts, in contrast to 1 of 6 ETT samples, as previously described in 2 of 3 ETT samples. The transcriptomic analysis allowed robust clustering of ETTs distinct from the APSN/PSN group but failed to differentiate APSNs from PSNs. Indeed, only 7 genes were differentially expressed between PSN and APSN samples; CCL19 upregulation and EPCAM downregulation were the most distinguishing features of APSNs. In contrast, 80 genes differentiated ETTs from APSNs, establishing a molecular signature for ETT. Gene set analysis identified significant enrichments in the DNA damage repair, immortality and stemness, and cell cycle signaling pathways when comparing ETTs and APSNs. These results suggested that APSN might not represent a distinct entity but rather a transitional stage between PSN and ETT. RNA sequencing and the transcriptional signature of ETT described herein could serve as triage for APSN from curettage or biopsy material, enabling the identification of cases that need further clinical investigations.

Application of Current Pathologic Criteria for Atypical Placental Site Nodule Suggests That Refined Criteria Are Needed.

Atypical placental site nodules (APSNs) are histologically intermediate between placental site nodules (PSNs) and epithelioid trophoblastic tumors (ETTs). Little data exists to characterize these lesions and the risk of transformation from PSN to ETT. Recent World Health Organization (WHO) criteria for distinction of APSN are vague and not objectively defined. We identified cases signed out as PSN (n=33) and APSN (n=11) and aimed to characterize, statistically compare, and assess the risk of transformation in PSNs using data including size, location, mitotic rate, Ki-67 proliferation index, trophoblastic cells per high-power field, presence of severe cytologic atypia, beta-human chorionic gonadotropin levels, time since last pregnancy, presence of calcification, necrosis, or apoptosis, and follow-up results. All cases were confirmed to be positive for p63, and a Ki-67/AE1/AE3 dual stain was used to evaluate the Ki-67 proliferation index in the trophoblastic cells. In our cohort, slight changes in the interpretation of WHO criteria for PSN and APSN led to marked differences in the proportion of PSNs flagged as "atypical." There was no statistically significant difference in the persistence of APSN versus non-APSN. None of the PSNs transformed to ETT. Current criteria for distinction between PSN and APSN are largely subjective. More objective, clearly defined, and clinically meaningful criteria are needed to distinguish between PSN and APSN, thus aiding in assessing the rare risk of transformation to ETT.

Placental Site Trophoblastic Tumor in Mediastinal Recurrence of Mixed Germ Cell Tumor of the Testis: Report of a Case and Review of the Literature.

We present a rare case of a 42-year-old man diagnosed with a placental site trophoblastic tumor in combination with teratoma in a mediastinal recurrence of a testicular germ cell tumor post-orchiectomy and chemotherapy. To the best of our knowledge, this is the eighth case of placental site trophoblastic tumor in a male reported so far in the English literature. The purpose of this case report is to add data to the existing literature, review the literature, discuss the differential diagnoses with emphasis on morphologic and immunohistochemical differences between trophoblastic tumors, and highlight the management implications of a correct diagnosis.

A Review of Current Management of Placental Site Trophoblastic Tumor and Epithelioid Trophoblastic Tumor.

IMPORTANCE: Placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) are rare forms of gestational trophoblastic neoplasia (GTN). These tumors differ from choriocarcinoma as they are monophasic, have slower growth rates, have lower ß-hCG concentrations, and are more chemoresistant. Placental site trophoblastic tumor and ETT can be misdiagnosed, leading to inappropriate management.. OBJECTIVE: The aim of this study was to review the pathogenesis, presentation, pathologic findings, and treatment for PSTT and ETT. EVIDENCE ACQUISITION: A comprehensive literature review was performed identifying relevant research and review articles. Relevant textbook chapters and guidelines were also reviewed. RESULTS: Placental site trophoblastic tumor and ETT can present months to years after any antecedent pregnancy event with abnormal uterine bleeding and an elevated ß-hCG. Tumors are typically confined to the uterus and secrete lower levels of ß-hCG compared with other GTNs. The International Federation of Gynecology and Obstetrics prognostic scoring system does not correlate well with prognosis. These lesions can be misdiagnosed as smooth muscle tumors, metastatic melanoma, and cervical squamous cell carcinoma. However, they can be distinguished by their unique histologic and immunophenotypic features. CONCLUSIONS: Surgery is the mainstay of treatment for early-stage PSTT and ETT. For patients with advanced disease or for those with poor prognostic indicators, such as an antecedent pregnancy interval of greater than 48 months, a multimodal treatment paradigm of surgery and chemotherapy using a high-risk GTN platinum-etoposide containing regimen is recommended. RELEVANCE: Placental site trophoblastic tumor and ETT should be considered in the differential diagnosis in a reproductive age patient presenting with abnormal uterine bleeding and an elevated ß-hCG after any antecedent pregnancy event.

Coexisting Epithelioid Trophoblastic Tumor and Placental Site Trophoblastic Tumor During Asymptomatic Relapse: A Case Report and Literature Review.

Gestational trophoblastic neoplasms are a group of trophoblastic tumors that include choriocarcinoma (CC), epithelioid trophoblastic tumors (ETTs), and placental site trophoblastic tumors (PSTTs). Mixed gestational trophoblastic neoplasms include combinations of CCs with ETTs and/or PSTTs; combinations of ETTs and PSTTs have also been described. This report describes the case of a 49-yr-old female with mixed ETT and PSTT discovered due to menstrual delay and a positive beta-human chorionic gonadotropin in serum 11 yr after normal pregnancy; it is an asymptomatic recurrence of the neoplasm after 2 yr. Moreover, only the ETT recurred without evidence of PSTT by biopsy and without any increase in human chorionic gonadotropin levels, even though human chorionic gonadotropin was positive in the first onset of the disease. We also reviewed published English literature, which revealed that there are only 36 cases of mixed trophoblastic tumors to date, of which pure mixed ETT and PSTT were reported only in four cases including our case. The most common combination is CC admixed with an ETT (52%), followed by CC with PSTT in 30.5%. CC admixed with an ETT and/or PSTT account for 83% of the cases, of which pure mixed ETT and PSTT were reported only in 4 cases (11%). The rarity of this condition entails reporting of all cases to facilitate future research and clinical management.

Placental Site Trophoblastic Tumor in a Pulmonary Vascular Malformation With Spontaneous Pneumothorax.

Placental site trophoblastic tumor, a rare variety of gestational trophoblastic disease, is traditionally limited to the uterus, found within the placental implantation site where it can lead to arteriovenous malformations. Gestational trophoblastic diseases are known to metastasize to the lungs, of which choriocarcinomas are the most common. However arteriovenous malformations related to such metastatic lesions are extremely rare. The occurrence of spontaneous pneumothorax in pulmonary arteriovenous malformations, under any circumstances, is rarely reported. Herein we report a rare case of metastatic placental site trophoblastic tumor found within pulmonary arteriovenous malformations uniquely presenting with spontaneous pneumothorax.

Gestational trophoblastic neoplasia after human chorionic gonadotropin normalization in a retrospective cohort of 7761 patients in France.

BACKGROUND: The risk of malignant transformation of molar pregnancies after human chorionic gonadotropin levels return to normal is low, roughly 0.4%, but may justify an adaptation of monitoring strategies for certain patients. OBJECTIVE: This study aimed to determine the risk of gestational trophoblastic neoplasia after human chorionic gonadotropin normalization in women with molar pregnancy and identify risk factors for this type of malignant transformation to optimize follow-up protocols after human chorionic gonadotropin normalization. STUDY DESIGN: This was a retrospective observational national cohort study based at the French National Center for Trophoblastic Diseases of 7761 patients, treated between 1999 and 2020 for gestational trophoblastic disease, whose human chorionic gonadotropin levels returned spontaneously to normal. RESULTS: Among 7761 patients whose human chorionic gonadotropin levels returned to normal, 20 (0.26%) developed gestational trophoblastic neoplasia. The risk of malignant transformation varied with the type of mole, from 0% (0 of 2592 cases) for histologically proven partial mole to 0.36% for complete mole (18 of 5045) and 2.1% (2 of 95) for twin molar pregnancy. The median time to diagnosis of malignant transformation after human chorionic gonadotropin normalization was 11.4 months (range, 1-34 months). At diagnosis, 16 of 20 patients (80%) had the International Federation of Gynecology and Obstetrics stage I tumor, and 10 of 20 patients (50%) had a tumor classified as low risk in terms of the International Federation of Gynecology and Obstetrics score. In 9 of 20 patients (45%), the most common first-line treatment was combination chemotherapy. A quarter of these tumors (5 of 20) were histologically proven placental site or epithelioid trophoblastic tumors. In univariate analysis, the factors significantly associated with a higher risk of developing gestational trophoblastic neoplasia after the end of the normal human chorionic gonadotropin monitoring period were age of ≥45 years (odds ratio, 8.3; 95% confidence interval, 2.0-32.7; P=.004) and time to human chorionic gonadotropin normalization of ≥8 weeks (odds ratio, 7.7; 95% confidence interval, 1.1-335; P=.03). The risk was even higher for human chorionic gonadotropin normalization times of ≥17 weeks (odds ratio, 19.5; 95% confidence interval, 3.3-206; P<.001). CONCLUSION: In this group of patients with gestational trophoblastic disease, none of the those with pathologically verified partial mole had malignant transformation, supporting the current recommendation of stopping human chorionic gonadotropin monitoring after 3 successive negative tests. In cases of complete mole or twin molar pregnancy, we proposed to extend the monitoring period with quarterly human chorionic gonadotropin measurements for an additional 30 months in patients with the identified risk factors for late malignant transformation (age, ≥45 years; time to human chorionic gonadotropin normalization, ≥8 weeks).

Gestational trophoblastic neoplasia: Novelties and challenges.

Gestational trophoblastic diseases are a group of pregnancy-related disorders, originated from trophoblast cells. They include benign and aggressive tumors, such as the invasive mole, the choriocarcinoma, the placental site trophoblastic tumor (PSTT), and the epithelioid trophoblastic tumor (ETT). These malignancies are characterized as gestational trophoblastic neoplasm (GTN), rarer, although more dangerous. The diagnosis of GTN is made in most cases by monitoring serum chorionic gonadotropin (hCG) with histological confirmation. The use of specific tissue biomarkers has been increasingly employed as a differential diagnosis, leading to more accurate results and different therapy protocols and prognosis for each GTN. The treatment is based on the International Federation of Gynecology and Obstetrics anatomical staging system and the World Health Organization prognostic score system. If an accurate diagnosis is made and the guidelines followed, the cure for choriocarcinoma and invasive mole cases can reach 98%, whereas PSTT and ETT still present mild success rates. The improved knowledge about GTN and its peculiarities allows physicians to efficiently achieve the differential diagnosis and choose the best available therapy protocol, thus increasing the overall survival of affected women. Nevertheless, obtaining epidemiological data and improving knowledge through basic and translational research are essential to answer open questions on GTN physiopathology, their causes, and cellular behavior.

Placental site trophoblastic tumour: five challenges of patient clinical management.

Placental site trophoblastic tumour is a rare form of gestational trophoblastic disease accounting for about 1%-2% of all trophoblastic tumours. Diagnosis and management of placental site trophoblastic tumour can be difficult.We report a case of a 30-year-old woman diagnosed with a placental site trophoblastic tumour and identify the challenges in diagnosis and treatment of this rare situation. The presenting sign was abnormal vaginal bleeding that started 3 months after delivery. Image exams revealed an enlarged uterus with a heterogeneous mass, with vesicular pattern, and the increased vascularisation serum human chorionic gonadotropin level was above normal range. The histological diagnosis was achieved through hysteroscopic biopsy. Staging exams revealed pulmonary micronodules. The patient was successfully treated with hysterectomy and chemotherapy. The latest follow-up (37 months after diagnosis) was uneventful, and the patient exhibited no signs of recurrence or metastasis.

"It's not lupus". A placental site trophoblastic tumor presenting as a lupus-like paraneoplastic syndrome. A grand round case.

Introduction: Placental site trophoblastic tumor (PSTT) is a rare subtype of gestational trophoblastic disease. Association of PSTT and nephrotic syndrome is exceedingly rare and has been described in 8 cases thus far. In all cases hysterectomy was performed within months after onset of symptoms, leading to immediate remission of nephrotic syndrome, except for one patient who died of complications of PSTT. Case: We describe the history of a woman in which PSTT was discovered years after onset of nephrotic syndrome. Kidney biopsy revealed lupus-like mesangiocapillary nephritis and over time the patient developed additional symptoms mimicking systemic lupus erythematosus (SLE). Discussion: We provide an overview of the literature on this clinical entity and elaborate on its pathophysiology. In addition, we reflect on the phenomenon of anchoring bias, that led physicians to assume the patient had SLE without questioning this diagnosis in the light of the unexplained finding of increased tumor markers.

Treatment of gestational trophoblastic disease in the 2020s.

PURPOSE OF REVIEW: This review demonstrates the evidence for new systemic anticancer treatments and how they integrate within conventional management for gestational trophoblastic neoplasia (GTN). We present the evidence on atypical placental site nodules, and how they incorporate within the GTN spectrum, as well as updates regarding GTN staging and follow-up. RECENT FINDINGS: First-line treatment for GTN still lies in conventional chemotherapy, although the introduction of anti-PD1/PD-L1 immune checkpoint inhibitors has shown significant promise in management of relapsed disease, with responses reported in multiple relapsed choriocarcinomas as well as epithelioid trophoblastic tumours and placental site trophoblastic tumours (ETT/PSTT). Following completion of treatment, ETT/PSTT still require life-long surveillance but for other GTN, no recurrences have been detected after 7 years. SUMMARY: Checkpoint inhibitors are likely to play an increasing role in the future management of GTN management. Further refinement of prognostic factors to identify those most at risk of GTN recurrence is warranted so that surveillance can be focussed on those most at risk, whilst minimizing unnecessary intervention for those at lower risk.

Whole transcriptome analysis of gestational trophoblastic neoplasms reveals altered PI3K signaling pathway in epithelioid trophoblastic tumor.

OBJECTIVE: Genomic characteristics of gestational trophoblastic neoplasm (GTN) are mostly unknown. This study reveals the molecular features of malignant GTN, including choriocarcinoma (CC), epithelioid trophoblastic tumor (ETT), and placental site trophoblastic tumor (PSTT), by whole transcriptome sequencing analysis. METHODS: Data obtained from the total RNA sequencing of 2 CC, 4 ETT, and 4 PSTT were evaluated for differential gene expression, pathway alteration, fusion gene, infiltrating immune cell type, PD-L1 and PTEN expression level, and mutation analysis was performed. RESULTS: The transcriptome data were correlated with known biomarkers, including HDS3B1, p63, hCG, and hPL for all tumor types. ETT and PSTT were more closely clustered compared with CC in clustering analysis using gene expression; however, ETT showed various altered signaling pathways, including PI3K-Akt-mTOR, with frequent loss of PTEN protein expression. This finding was both well correlated with PIK3CA c.3140A > G pathogenic mutation, detected in 1 ETT, and further confirmed using the MassARRAY method. PSTT showed an overexpressed gene cluster associated with muscle contraction and G protein-coupled receptor activity. No significant fusion gene was seen in all 10 cases. In tumor-infiltrating immune cell profiles, CD4 memory T cell and macrophage signature were relatively high in ETT and PSTT. PD-L1 mRNA expression level was high in all cases, which was significantly correlated with the PD-L1 level by immunohistochemistry (p = 0.03) with positivity in all 10 cases. CONCLUSIONS: ETT and PSTT were similar at the transcriptome level, with a high level of PD-L1 expression in all tumor types; however, specific pathways, such as PI3K signaling, were altered in ETT.

Ovarian Intermediate Trophoblastic Tumors: Genotyping Defines a Distinct Category of Nongestational Tumors of Germ Cell Type.

Trophoblastic neoplasms involving the ovary are uncommon and include gestational tumors, which are either metastatic from the uterus or ectopic and nongestational tumors, which include those of germ cell type/origin and somatic tumors with trophoblastic differentiation; in all these types, most are pure choriocarcinoma. Intermediate trophoblastic tumors, which include placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT), are rare in the ovary, with most assumed to be gestational; this is the only category formally recognized in 2014 World Health Organization (WHO) classification, likely due to few well-documented nongestational examples. We report the clinicopathologic features of 6 ovarian intermediate trophoblastic tumors, including 3 PSTTs, 2 ETTs, and 1 ETT with choriocarcinomatous differentiation. DNA-based short tandem repeat genotyping identified 4 of these as nongestational (3 PSTTs and 1 ETT), as evidenced by sharing of alleles between tumor and normal tissue at all informative loci. Interestingly, all 3 of the nongestational PSTTs coexisted with mature cystic teratoma. The remaining 2 tumors (1 ETT and 1 ETT with some choriocarcinomatous differentiation) were gestational (likely ectopic due to lack of evidence of a uterine tumor), as evidenced by the presence of both maternal and novel/nonmaternal alleles at informative loci in tumor compared with normal tissue. It is important to recognize a distinct category of primary ovarian nongestational intermediate trophoblastic tumors of germ cell type/origin, including PSTT and ETT, in classification systems to guide clinical management, as gestational and nongestational tumors have different genetic origins and may require different therapy. Genotyping is useful for classification as nongestational versus gestational, particularly as traditional clinicopathologic findings cannot always predict the nature of a trophoblastic tumor.

lnc003875/miR-363/EGR1 regulatory network in the carcinoma -associated fibroblasts controls the angiogenesis of human placental site trophoblastic tumor (PSTT).

The rare gestational trophoblastic neoplasia placental site trophoblastic tumor (PSTT) frequently demonstrates a high degree of vascularization, which may facilitate the tumor metastasis. However, the underlying mechanisms remain largely unknown. In the present study, we found that early growth response 1 (EGR1) was highly expressed in the carcinoma-associated fibroblasts (CAFs) of PSTT tissues. Further data showed that miR-363 down-regulated EGR1 expression whereas long non-coding RNA NONHSAT003875 (lnc003875) up-regulated EGR1 expression in PSTT derived CAFs. lnc003875 exerted no effect on miR-363 expression, but it recovered the decrease of EGR1 caused by miR-363 mimic. The conditioned media from PSTT CAFs treated with miR-363 mimic abrogated the tube formation capacity of human umbilical vein endothelial cells (HUVECs), which can be partially restored by lnc003875 over-expression. Moreover, over-expression of EGR1 promoted the secretion of Angiopoietin-1 (Ang-1) in PSTT derived CAFs and improved the tube formation of HUVECs, which could be effectively abrogated by Ang-1 siRNAs. In vivo vasculogenesis assay demonstrated that lnc003875/EGR1 in PSTT derived CAFs promoted the vasculogenesis of HUVECs in C57BL/6 mice. Collectively, these findings indicated that lnc003875/miR-363/EGR1/Ang-1 in CAFs may be crucial for the angiogenesis of PSTT.