Serum Levels of MicroRNA-371a-3p for Predicting the Histology of Postchemotherapy Residual Masses of Germ Cell Tumours.

BACKGROUND AND OBJECTIVE: Serum levels of microRNA-371a-3p (M371) represent a novel and sensitive biomarker of germ cell tumours (GCTs). This study analysed the utility of M371 to identify viable cancer (VC) in postchemotherapy (pc) residual masses with the underlying goal of avoiding overtreatment. METHODS: A multicentric, prospective diagnostic study was conducted in 180 GCT patients undergoing pc resection of residual masses. A correlation of M371 measurement results with the histological presence of VC in masses was found. A receiver operating characteristic analysis was performed for exploring the performance characteristics of the test. KEY FINDINGS AND LIMITATIONS: The sensitivity was found to be 68.9%, specificity 99.3%, area under the curve 0.813, positive predictive value 0.969, and negative predictive value 0.905; sensitivity is significantly associated with the percentage of VC in the mass. In specimens with ≤10% VC, there were 33.3% elevated M371 levels as opposed to 85.7% in specimens with >50% VC. Teratoma and somatic-type malignancy do not express M371. A lack of a central pathological review is a limitation. CONCLUSIONS AND CLINICAL IMPLICATIONS: The M371 test can identify 68.9% of patients with VC in pc masses. However, cases with <10% VC in the mass may escape detection. Teratoma does not express M371. The test alone cannot correctly identify patients requiring pc surgery, but it may be a tool for scheduling the extent of surgery. PATIENT SUMMARY: The microRNA-371a-3p (M371) test can identify about two-thirds of patients with viable cancer in residual metastatic masses following chemotherapy for germ cell tumours. Only masses with high percentages of viable cancer cells can be identified, and the histological subtype teratoma remains undetected with the test.

HIVEC as an alternative option in non-muscle-invasive bladder cancer: Experiences from a high-volume center.

BACKGROUND: High risk non-muscle invasive bladder cancer (NMIBC) is usually treated with intravesical BCG-therapy. In case of BCG failure radical cystectomy (RC) is the treatment of choice. Nevertheless, many patients are unfit for or unwilling to undergo RC. Hyperthermic intravesical chemotherapy (HIVEC) is a promising bladder sparing therapy in such cases. It was the purpose of the study to evaluate the efficacy of HIVEC in patients with BCG failure as well as in BCG naïve patients in case of BCG shortage or given contra-indications for BCG. METHODS: We analyzed the first 60 patients who received hyperthermic intravesical chemotherapy (HIVEC) at our department. The therapy regimen consisted of an induction course of 6 weekly sessions, followed by a maintenance course with 6 monthly sessions. Fluorescence cystoscopy with urine cytology and bladder mapping was performed after completion of induction and maintenance therapy at 3 and 12 months. About 68.6 % had received a recurrence after or during BCG treatment, 55% of the subjects were BCG-unresponsive NMIBC according to EAU guidelines. RESULTS: The median follow up was 12 months with 12 cycles of HIVEC therapy being administered on average, representing completion of induction and maintenance therapy with 6 cycles each. The 1- and 2-year recurrence-free-survival (RFS) was 67% and 40% respectively. Only one out of 60 patients developed progression to muscle invasion with progression-free-survival (PFS) of 98% at 2 years. No statistical differences were found in RFS for patients failure to BCG compared to patients that were BCG-naïve (BCG unresponsive vs. BCG-naïve) and patients that carried carcinoma in situ (CIS) compared to patients without CIS (CIS vs. no CIS). CONCLUSION: Chemohyperthermia using HIVEC results in high recurrence-free survival and a 2-year progression-free survival rate of 98% with a bladder preservation rate of almost 80%. Comparing our data, HIVEC shows better oncological results together with better tolerability and safety making HIVEC a good alternative for patients who refuse radical cystectomy or who are ineligible for radical cystectomy.

Impact of teratoma on survival probabilities of patients with metastatic non-seminomatous germ cell cancer: Results from the IGCCCG Update Consortium.

AIMS: To resolve the ongoing controversy surrounding the impact of teratoma (TER) in the primary among patients with metastatic testicular non-seminomatous germ-cell tumours (NSGCT). PATIENTS AND METHODS: Using the International Germ Cell Cancer Collaborative Group (IGCCCG) Update Consortium database, we compared the survival probabilities of patients with metastatic testicular GCT with TER (TER) or without TER (NTER) in their primaries corrected for known prognostic factors. Progression-free survival (5y-PFS) and overall survival at 5 years (5y-OS) were estimated by the Kaplan-Meier method. RESULTS: Among 6792 patients with metastatic testicular NSGCT, 3224 (47%) had TER in their primary, and 3568 (53%) did not. In the IGCCCG good prognosis group, the 5y-PFS was 87.8% in TER versus 92.0% in NTER patients (p = 0.0001), the respective 5y-OS were 94.5% versus 96.5% (p = 0.0032). The corresponding figures in the intermediate prognosis group were 5y-PFS 76.9% versus 81.6% (p = 0.0432) in TER and NTER and 5y-OS 90.4% versus 90.9% (p = 0.8514), respectively. In the poor prognosis group, there was no difference, neither in 5y-PFS [54.3% in TER patients versus 55.4% (p = 0.7472) in NTER], nor in 5y-OS [69.4% versus 67.7% (p = 0.3841)]. NSGCT patients with TER had more residual masses (65.3% versus 51.7%, p < 0.0001), and therefore received post-chemotherapy surgery more frequently than NTER patients (46.8% versus 32.0%, p < 0.0001). CONCLUSION: Teratoma in the primary tumour of patients with metastatic NSGCT negatively impacts on survival in the good and intermediate, but not in the poor IGCCCG prognostic groups.

Cost-effectiveness analysis of different treatment modalities in BCG-unresponsive NMIBC.

OBJECTIVE: Radical cystectomy (RC) is the standard of care (SOC) in BCG-unresponsive NMIBC and is associated with a significant health-related quality-of-life burden. Recently, promising results have been published on Gemcitabine/Docetaxel, Pembrolizumab, and Hyperthermic Intravesical Chemotherapy (HIVEC) as salvage therapy options trying to increase the rate of bladder preservation. Here, we performed a Cost-Effectiveness-Analysis of those treatment modalities. PATIENTS AND METHODS: We developed a Markov model from a payer's perspective drawing on clinical data of single-arm trials testing intravesical gemcitabine/docetaxel and pembrolizumab in BCG-unresponsive NMIBC, as well as clinical data from patients receiving hyperthermic intravesical chemotherapy HIVEC (n = 29) as intravesical salvage chemotherapy at our uro-oncological centre in Cologne. Costs were simulated utilising a non-commercial diagnosis-related groups grouper, utilities were derived from comparable cost-effectiveness studies. We used a Monte Carlo simulation to identify the optimal treatment, comparing the incremental cost effectiveness ratios (ICERs) at a willingness-to-pay threshold of €50 000 (euro)/quality-adjusted life year (QALY). RESULTS: Over a horizon of 10 years, gemcitabine/docetaxel, HIVEC, and pembrolizumab were associated with costs of €48 353, €64 438, and €204 580, as well as a gain of QALYs of 6.16, 6.48, and 6.00, resulting in an ICER of €26 482, €42 567, and €184 533 respectively, in comparison to RC with total costs of €21 871 and a gain of QALYs of 5.01. Monte Carlo simulation identified HIVEC as the treatment of choice under assumption of a WTP of <€50 000. CONCLUSION: Considering a WTP of <€50 000/QALY, gemcitabine/docetaxel and HIVEC are highly cost-effective therapeutic options in BCG-refractory NMIBC, while RC remains the cheapest option. At its current price, pembrolizumab would only be cost-effective assuming a price reduction of at least 70%.

[Palliative surgery for metastatic prostate cancer]. / Palliative Chirurgie des metastasierten Prostatakarzinoms.

Androgen deprivation in combination with novel hormonal agents, docetaxel, or in combination with abiraterone/prednisone plus docetaxel or darolutamid plus docetaxel represent the standard therapeutic approach in metastatic hormone-sensitive prostate cancer (mHSPC). Patients with low-risk prostate cancer also benefit from additional radiation therapy or radical prostatectomy in terms of progression-free and overall survival. Despite favorable response rates, basically all patients will develop castration resistant prostate cancer (CRPC) within 2.5 to 4 years. In addition to systemic chemotherapy, second-line hormonal treatment of systemic application of radionuclides such as radium223 or 177Lu-PSMA represent salvage management options. However, nowadays about 50-65% of patients will develop symptoms due to local progression of prostate cancer which is the result of improved oncological outcomes with significantly prolonged survival times due to the new medical treatment options. Management of such symptomatic local progression will become more important in upcoming years so that all uro-oncologists need to be aware of the various surgical management options. Complications of the lower urogenital tract such as recurrent gross hematuria ± bladder clotting and with the necessity for red blood cell transfusions, subvesical obstruction and acute urinary retention, rectourethral or rectovesical fistulas might be managed by palliative surgery such as palliative transurethral resection of the prostate (TURP), radical cystectomy, radical cystoprostatectomy with urinary diversion, and pelvic exenteration. Symptomatic or asymptomatic obstruction of the upper urinary tract might be managed by endoluminal or percutaneous urinary diversion, ureteral reimplantation, ileal ureter replacement, or implantation of the Detour® system (Coloplast GmbH, Hamburg, Germany).

Salvage vesiculectomy for local prostate cancer recurrence: surgical technique and early post-operative outcomes.

PURPOSE: Isolated recurrence in remnants of the seminal vesicles (SV) after treatment of primary prostate cancer (PCa) has become a more frequent entity with the widespread use of more sensitive next-generation imaging modalities. Salvage vesiculectomy is hypothesized to be a worthwhile management option in these patients. The primary goal of this study is to describe the surgical technique of this new treatment option. Secondary outcomes are peri- and post-operative complications and early oncological outcomes. METHODS: Retrospective multicenter study, including 108 patients with solitary recurrence in the SV treated between January 2009 and June 2022, was performed. Patients with local recurrences outside the SVs or with metastatic disease were excluded. Both SVs were resected using a robot-assisted or an open approach. In selected cases, a concomitant lymphadenectomy was performed. RESULTS: Overall, 31 patients (29%) reported complications, all but one grade 1 to 3 on the Clavien-Dindo Scale. A median PSA decrease of 2.07 ng/ml (IQR: 0.80-4.33, p < 0.001), translating into a median PSA reduction of 92% (IQR: 59-98%) was observed. At a median follow-up of 14 months, freedom from secondary treatment was 54%. Lymphadenectomy had a significant influence on PSA reduction (p = 0.018). CONCLUSION: Salvage vesiculectomy for PCa recurrence limited to the SV is a safe procedure with excellent PSA response and is a potential curative treatment in a subset of patients. A concomitant lymphadenectomy can best be performed in all patients that did not underwent one at primary treatment.

[Palliative urologic surgery for metastatic prostate cancer: what needs to be considered in the future?] / Palliative Urologische Chirurgie des metastasierten Prostatakarzinoms: was müssen wir zukünftig berücksichtigen?

Androgen deprivation in combination with novel hormonal agents, docetaxel or the combination of abiraterone/prednisone plus docetaxel or darolutamide plus docetaxel represent the standard therapeutic approach in metastatic hormone-sensitive prostate cancer (mHSPC). Patients with low-risk prostate cancer also benefit from additional radiation therapy or radical prostatectomy in terms of progression-free and overall survival. Despite favourable response rates, basically all patients will develop castration-resistant prostate cancer (CRPC) within 2.5 to 4 years. Systemic chemotherapy, second-line hormonal treatment or systemic application of radionuclides such as Radium-223 or 177Lu-PSMA represent salvage management options. As the new medical treatment options have led to an improved oncological outcome with significantly prolonged survival times, about 50% to 65% of patients will develop symptoms due to local progression of prostate cancer. The management of such symptomatic local progression will become more important in upcoming years, which means that all uro-oncologists need to be aware of the various surgical management options. If complications of the lower urogenital tract occur, for example repetitive gross haematuria with or without bladder clotting and with the necessity for red blood cell transfusions, subvesical obstruction, acute urinary retention or rectourethral or rectovesical fistulas, these may be managed by palliative surgery such as palliative TURP, radical cystectomy, radical cystoprostatectomy with urinary diversion, and pelvic exenteration. Symptomatic or asymptomatic obstruction of the upper urinary tract can be managed by endoluminal or percutaneous urinary diversion, ureteral reimplantation, ileal ureter replacement, or implantation of a Detour system. However, an individualised and risk-adapted treatment strategy needs to be developed for each single patient to achieve an optimal therapeutic outcome with improvement of both symptoms and quality of life. In specific clinical situations, best supportive care may be an adequate option.

Assessing the risk to develop a growing teratoma syndrome based on molecular and epigenetic subtyping as well as novel secreted biomarkers.

In germ cell tumors (GCT), a growing teratoma during chemotherapy with decreasing tumor markers was defined as 'growing teratoma syndrome' (GTS) by Logothetis et al. in 1982. So far, its pathogenesis and specific treatment options remain elusive. We aimed at updating the GTS definition based on molecular and epigenetic features as well as identifying circulating biomarkers. We selected 50 GTS patients for clinical characterization and subsequently 12 samples were molecularly analyzed. We further included 7 longitudinal samples of 2 GTS patients. Teratomas (TER) showing no features of GTS served as controls. GTS were stratified based on growth rates into a slow (<0.5 cm/month), medium (0.5-1.5) and rapid (>1.5) group. By analyzing DNA methylation, microRNA expression and the secretome, we identified putative epigenetic and secreted biomarkers for the GTS subgroups. We found that proteins enriched in the GTS groups compared to TER were involved in proliferation, DNA replication and the cell cycle, while proteins interacting with the immune system were depleted. Additionally, GTSrapid seem to interact more strongly with the surrounding microenvironment than GTSslow. Expression of pluripotency- and yolk-sac tumor-associated genes in GTS and formation of a yolk-sac tumor or somatic-type malignancy in the longitudinal GTS samples, pointed at an additional occult non-seminomatous component after chemotherapy. Thus, updating the Logothetis GTS definition is necessary, which we propose as follows: The GTS describes a continuously growing teratoma that might harbor occult non-seminomatous components considerably reduced during therapy but outgrowing over time again.

Cystic Pelvic Masses in Men: A Presentation of Uncommon Cases and a Literature Review.

Unclear cystic masses in the pelvis in male patients are a rare situation and could be of benign or malignant origin. The underlying diseases demand for specific diagnostic and therapeutic approaches. We present a case series of 3 male patients with different clinical symptoms (perineal pain, urinary retention and a large scrotal cyst) related to cystic lesions in the pelvic region. On all patients initial histopathological workup was unclear. All patients underwent surgery with complete resection of the tumor which revealed a broad spectrum of histopathological findings: unusual form of cystic adenocarcinoma of the prostate, malignant transformation of a dysontogenetic cyst, and finally a very rare diagnosis of a malignant tumor of the Cowper gland. This case series and literature review provide clues for a possible diagnostic and therapeutic approach in the case of unclear pelvic cystic masses and could support urologists during the therapy selection in the future.

Adjunctive Surgery Is Often Without Oncological Benefit at Time of Postchemotherapy Retroperitoneal Lymph Node Dissection.

PURPOSE: Postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) for advanced nonseminomatous germ cell tumors (GCTs) aims to resect all remaining metastatic tissue. Resection of adjacent visceral or vascular organs is commonly performed for complete resection. Resection of organs harboring only necrosis results in relevant overtreatment. The study aimed to describe the frequency of metastatic involvement of resected organs with teratoma or viable cancer and to analyze perioperative complications and relapse-free survival. MATERIALS AND METHODS: In a 2-center study, we reviewed a cohort of 1204 patients who underwent PC-RPLND between 2008 and 2021 and identified 242 (20%) cases of adjunctive surgery during PC-RPLND. We analyzed the removed adjacent structures and the pathohistological presence of GCT elements in the resected organs: viable GCT, teratoma, or necrosis/fibrosis. Surgery-associated complications were reported according to the Clavien-Dindo classification. RESULTS: Viable GCT, teratoma, and necrosis were present in 54 (22%), 94 (39%), and 94 (39%), respectively, of all patients with adjunctive resection of adjacent organs. Vascular resections or reconstructions (n = 112; viable: 23%, teratoma: 41%, necrosis: 36%) were performed most frequently, followed by nephrectomies (n = 77; viable: 29%, teratoma: 39%, necrosis: 33%). Perioperative complications of grade ≥ IIIa occurred in 6.6% of all patients, with no difference between the viable GCT and teratoma/necrosis groups (P = .1). A total of 76 patients have been followed without a relapse for at least 36 months. Median follow-up of the whole cohort was 22 months (quartile 7 and 48). Patients with viable GCT/teratoma in the resected specimens had a significantly increased risk of recurrence by 5 years compared to patients with only necrosis (19% vs 59% vs 81%, P < .001). CONCLUSIONS: This study shows that 33% to 40% of all resections of adjacent organs do not harbor teratoma or viable GCT. This highlights the need for better patient selection for these complex patients.

Detection of Recurrence through microRNA-371a-3p Serum Levels in a Follow-up of Stage I Testicular Germ Cell Tumors in the DRKS-00019223 Study.

PURPOSE: Surveillance of clinical stage I (CSI) testicular germ cell tumors (GCT) is hampered by low sensitivity and specificity of current biomarkers for detecting relapses. This study evaluated if serum levels of microRNA371a-3p (M371 test) can: (i) Accurately detect relapses, (ii) detect relapses earlier than conventional technology, and (iii) if elevated postoperative M371 levels may predict relapse. EXPERIMENTAL DESIGN: In a multicentric setting, 258 patients with testicular CSI GCT were prospectively followed by surveillance for a median time of 18 months with serial measurements of serum M371 levels, in addition to standard diagnostic techniques. Diagnostic characteristics of M371 for detecting relapses were calculated using ROC curve analysis. RESULTS: Thirty-nine patients recurred (15.1%), all with elevated M371 levels; eight without relapse had elevations, too. The test revealed the following characteristics: area under the ROC curve of 0.993, sensitivity 100%, specificity 96.3%, positive predictive value 83%, negative predictive value 100%. Earlier relapse detection with the test was found in 28%, with non-significant median time gain to diagnosis. Postoperative M371 levels did not predict future relapse. CONCLUSIONS: The sensitivity and specificity of the M371 test for detecting relapses in CSI GCTs are much superior to those of conventional diagnostics. However, post-orchiectomy M371 levels are not predictive of relapse, and there is no significant earlier relapse detection with the test. In all, there is clear evidence for the utility of the M371 test for relapse detection suggesting it may soon be ready for implementation into routine follow-up schedules for patients with testicular GCT.

Retroperitoneal Lymph Node Dissection in Clinical Stage IIA/B Metastatic Seminoma: Results of the COlogne Trial of Retroperitoneal Lymphadenectomy In Metastatic Seminoma (COTRIMS).

BACKGROUND: Radiation therapy and systemic chemotherapy are recommended treatment options in marker-negative clinical stage (CS) IIA/B seminoma. Despite high cure rates of 82-94%, both therapeutic options are associated with significant long-term toxicities. OBJECTIVE: To evaluate the feasibility, oncological efficacy, and treatment-associated morbidity of primary nerve-sparing retroperitoneal lymph node dissection (nsRPLND) in CS IIA/B seminoma. DESIGN, SETTING, AND PARTICIPANTS: A prospective, single-arm, clinical phase 2 trial including CS IIA/B seminoma patients was conducted. INTERVENTION: Primary nerve-sparing retroperitoneal lymphadenectomy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Relapse-free and overall survival, surgery-associated complications according to the Clavien-Dindo classification, and Kaplan-Meier methods for survival calculation were assessed. RESULTS AND LIMITATIONS: Thirty patients at a mean age of 39.1 (34-52) yr with marker-negative CS IIA and IIB seminomas were recruited. The median follow-up was 22 (8-30) mo. Nineteen (63%) and 11 (36%) patients were diagnosed with stages IIA and B, respectively, at the time of primary diagnosis. Fourteen (47%) and 16 (53%) patients were diagnosed with CS IIA and IIB, respectively, at the time of nsRPLND. Twenty-seven and three patients underwent open and robot-assisted nsRPLND, respectively. The median operating room time was 125 (115-145) min, median blood loss was <150 ml, and median time of hospitalization was 4.5 (3-9) d. Four (13%) patients experienced Clavien-Dindo grade 3a complications. Lymph node histology revealed seminoma in 25 (80%) patients; two and three patients demonstrated embryonal carcinoma and benign disease, respectively. Sixteen patients underwent a serum analysis of miR371 preoperatively, which predicted metastatic disease in 12/13 and benign histology in 3/3 patients. Three of 30 (10%) patients developed an outfield relapse 4, 6, and 9 mo postoperatively and were salvaged by systemic chemotherapy. Limitations are the low patient number and length of follow-up. CONCLUSIONS: The nsRPLND approach results in a high cure rate at midterm follow-up and is associated with a low frequency of treatment-associated morbidities, making this approach a feasible alternative to radiation therapy or systemic chemotherapy. PATIENT SUMMARY: The standard treatment of clinical stage IIA/B seminomas is radiation therapy or chemotherapy, which results in a significantly increased frequency of long-term toxicity and secondary neoplasms. In this trial, we demonstrate that nerve-sparing retroperitoneal lymph node dissection is a feasible therapeutic approach with low morbidity and high oncological efficacy.

[Emergencies in cancer therapy: surgical indications under systemic therapy]. / Notfälle in der medikamentösen Tumortherapie ­ Operative Indikationen unter Systemtherapie.

Emergency surgery due to side-effects of cancer therapy in patients with metastatic disease of the genitourinary tract is rare. Nevertheless, there are a number of emergencies that require rapid intervention and should be recognized by every uro-oncologist. The following review will work out important side-effects requiring surgical treatment, highlighting the main symptoms and the initial management.

Prediction models of incontinence and sexual function one year after radical prostatectomy based on data from 20 164 prostate cancer patients.

BACKGROUND: Incontinence and sexual dysfunction are long-lasting side effects after surgical treatment (radical prostatectomy, RP) of prostate cancer (PC). For an informed treatment decision, physicians and patients should discuss expected impairments. Therefore, this paper firstly aims to develop and validate prognostic models that predict incontinence and sexual function of PC patients one year after RP and secondly to provide an online decision making tool. METHODS: Observational cohorts of PC patients treated between July 2016 and March 2021 in Germany were used. Models to predict functional outcomes one year after RP measured by the EPIC-26 questionnaire were developed using lasso regression, 80-20 splitting of the data set and 10-fold cross validation. To assess performance, R2, RMSE, analysis of residuals and calibration-in-the-large were applied. Final models were externally temporally validated. Additionally, percentages of functional impairment (pad use for incontinence and firmness of erection for sexual score) per score decile were calculated to be used together with the prediction models. RESULTS: For model development and internal as well as external validation, samples of 11 355 and 8 809 patients were analysed. Results from the internal validation (incontinence: R2 = 0.12, RMSE = 25.40, sexual function: R2 = 0.23, RMSE = 21.44) were comparable with those of the external validation. Residual analysis and calibration-in-the-large showed good results. The prediction tool is freely accessible: https://nora-tabea.shinyapps.io/EPIC-26-Prediction/. CONCLUSION: The final models showed appropriate predictive properties and can be used together with the calculated risks for specific functional impairments. Main strengths are the large study sample (> 20 000) and the inclusion of an external validation. The models incorporate meaningful and clinically available predictors ensuring an easy implementation. All predictions are displayed together with risks of frequent impairments such as pad use or erectile dysfunction such that the developed online tool provides a detailed and informative overview for clinicians as well as patients.

Molecular and histopathological characterization of seminoma patients with highly elevated human chorionic gonadotropin levels in the serum.

Approximately 30% of seminoma (SEM) patients present with moderately elevated human chorionic gonadotropin (hCG) levels at first diagnosis. In case of high hCG serum levels, the presence of a non-SEM component, i.e. choriocarcinoma (CC), may be assumed. To characterize cases described as pure seminoma with high serum hCG levels, tissue samples and DNA were analyzed. Patient files from an international registry were screened for patients with SEM and extraordinarily high hCG serum levels. IHC and qRT-PCR analysis was performed for markers of SEM, embryonal carcinoma (EC) and CC/trophoblast cells. The cell lines TCam-2 (SEM), 2102EP, NCCIT, NT2/D1 (EC) and JAR, JEG3 and BeWo (CC) were included for comparison. Of 1031 SEM patients screened, 39 patients (3.7%) showed hCG serum levels > 1000 U/l. Of these, tumor material for IHC and RNA for qRT-PCR was available from n = 7 patients and n = 3 patients, respectively. Median pre-orchiectomy serum hCG level was 5356 U/l (range: 1224-40909 U/L). Histopathologically, all investigated samples were classified as SEM with syncytiotrophoblast sub-populations. SEM cells were SALL4+ / OCT3/4+ / D2-40+, while syncytiotrophoblast cells were hCG+ / GATA3+ / p63+ and SOX2-/CDX2-. qRT-PCR analysis detected trophoblast stem cell markers CDX2, EOMES and TFAP2C as well as the trophectoderm-specifier TEAD4, but not GATA3. Additionally, SOX17 and PRAME, but not SOX2, were detected, confirming the pure SEM-like gene expression signature of the analyzed samples. In conclusion, excessively increased hCG serum levels can appear in patients with pure SEM. To explain detectable hCG serum levels, it is important to diagnose the subtype of a SEM with syncytiotrophoblasts.