Mediastinal Germ Cell Tumors Research Articles

A case report of late detection of primary mediastinum herm cell tumor

Germ cell tumors are rare malignant neoplasms. Extragondal localization accounts for about 10% of all germ cell tumors, with up to 3% being mediastinal. The low incidence, along with a nonspecific clinical presentation, complicates initial diagnosis and leads to delays in diagnosis and the initiation of specific treatment. Primary care plays a crucial role in detecting such tumors and in patient routing. At the outpatient stage, the patient should be examined and referred to a specialized facility for specific treatment as quickly as possible. For differential diagnosis at the initial stages between mediastinal germ cell tumors and lymphoproliferative diseases, mediastinal sarcomas, thymomas, and others, monitoring tumor markers is necessary: alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (beta-HCG), and lactate dehydrogenase (LDH). When these markers are elevated and time is critical, it is permissible to start specialized antitumor treatment without histological confirmation.Currently, it is also important to consider the role of the new coronavirus infection, which complicates differential diagnosis at the initial stages. This article presents a clinical case of late detection of a germ cell tumor and attempts to conduct systemic therapy in the context of the disease’s complicated progression.

Mediastinal Teratoma with Angiosarcomatous Overgrowth in a Background of Vasculogenic Mesenchymal Tumor

Abstract Introduction/Objective Vasculogenic mesenchymal tumor refers to neoplastic reiteration of embryonic vasculogenesis. It is most commonly associated with nonseminomatous germ cell tumors of the mediastinum, in particular yolk sac tumor. In rare instances these lesions progress to angiosarcoma. Herein, we describe a case of angiosarcoma in a background of vasculogenic mesenchymal tumor in the setting of a mediastinal teratoma. Methods/Case Report A 33-year-old male, with a past medical history of anxiety, and right orchiectomy for testicular torsion, presented with shortness of breath, chest pain, and left arm swelling. Imaging studies demonstrated a mediastinal mass. Biopsy of the mass showed a germ cell tumor most compatible with a teratoma in the limited specimen. The patient received two rounds of chemotherapy and additional treatments were discontinued due to poor tolerance. Subsequent imaging showed continued increase in the size along with mass effect causing moderate to severe compression of the superior vena cava. Subsequently, the patient underwent resection of the mass. Grossly the mass was predominantly encapsulated with areas of capsular disruption. Sectioning revealed heterogeneous cut surfaces with fleshy, cystic, and necrotic areas. Morphologically the tumor was composed predominantly of teratomatous elements with areas of anastomosing atypical vascular channels within a hypocellular stroma suggestive of vascular genic mesenchymal as well as areas reminiscent of Masson lesion. Focally within these areas were malignant spindle cell proliferations compatible with angiosarcoma. The patient had an elevated AFP; however, no yolk sac tumor component was identified after thorough sampling. Final diagnosis of teratoma with angiosarcoma in a background of vasculogenic mesenchymal tumor was rendered after expert consultation. Results (if a Case Study enter NA) NA Conclusion Somatic-type malignancy and sarcomatous overgrowth are known to occur in mediastinal germ cell tumors; however, classification of the sarcomatous overgrowth can be challenging. Vasculogenic mesenchymal tumor is an exceedingly rare sarcomatous overgrowth that can rarely progress to angiosarcoma.

High-dose chemotherapy and peripheral blood stem cell transplantation as salvage therapy in primary mediastinal nonseminomatous germ cell tumors: The Indiana University experience.

Patients with relapsed primary mediastinal nonseminomatous germ cell tumor have low cure rates with salvage chemotherapy or surgery. The authors report survival outcomes of patients who received high-dose chemotherapy (HDCT) and peripheral blood stem cell transplantation (PBSCT) at Indiana University. The prospectively maintained Indiana University germ cell tumor database identified 32 patients with primary mediastinal nonseminomatous germ cell tumor who progressed after first-line cisplatin-based combination chemotherapy and received HDCT and PBSCT between 2006 and 2021. Therapy included two consecutive courses of HDCT consisting of 700 mg/m2 carboplatin and 750 mg/m2 etoposide, each for 3 consecutive days, and each followed by PBSCT. A second course was not given if the patient experienced progressive disease or prohibitive toxicity. Progression-free survival and overall survival were analyzed using the Kaplan-Meier method. Medians with 95% confidence intervals were also calculated along with 2-year probabilities. The median age at HDCT was 30 years (range, 18-61 years). With a median follow-up of 4.7 years (range, 1-14 years), the 2-year progression-free survival rate was 31% (95% confidence interval, 16%-47%), and the 2-year overall survival rate was 35% (95% confidence interval, 19%-52%). At last follow-up, nine patients (28%) remained without evidence of disease, including two platinum-refractory patients and two patients who were receiving HDCT as third-line therapy. There were three treatment-related deaths. Salvage HDCT and PBSCT is an active combination in patients who have relapsed primary mediastinal nonseminomatous germ cell tumor with curative potential and prolonged survival, including in platinum-refractory and third-line settings. The authors recommend this approach for initial salvage chemotherapy in this patient population.

Extended abstract: pathologic considerations concerning mediastinal germ cell tumors

Extended abstract: pathologic considerations concerning mediastinal germ cell tumors

Extragonadal germ cell tumors: A clinicopathologic study with emphasis on molecular features, clinical outcomes and associated secondary malignancies

Extragonadal germ cell tumors (EGCTs) are rare, representing <5% of all germ cell tumors (GCTs). Whilst EGCTs share morphological and immunohistochemical features with their gonadal counterparts, they tend to be more aggressive and are frequently associated with secondary somatic malignancies. The aim of our study was to evaluate the clinical, morphological and immunohistochemical features, and to analyze tumors for chromosomal abnormalities of 12p, in addition to any novel genetic alterations, in a series of EGCTs. Seventy-seven EGCTs were included. Anterior mediastinum was the most common anatomic site, followed by central nervous system, retroperitoneum, sacroccygeal area, and neck. Whole genome SNP array identified isochromosome 12p in 26% of tumors. Additional cytogenetic abnormalities included the presence of gain of chr 21 in 37% of tumors. Somatic-type malignancies were identified in 8% of patients. Disease progression (metastasis and/or recurrence) was documented in 8 patients, most of whom died from their relapse. Three patients who died of disease had somatic-type malignancies. Mediastinal seminomas had a significantly better overall survival when compared to mediastinal non-seminomatous GCTs. Our study demonstrates that EGCTs share similar histologic features, but diverse clinical outcomes compared to their gonadal counterparts. Outcomes vary according to anatomic location and histologic subtypes. Our data corroborate that somatic-type malignancies are frequently encountered in mediastinal EGCTs and that their presence portends a poorer prognosis.

Asymptomatic mature intrapericardial teratoma in an adult: a case report of a rare condition

BackgroundBenign mature teratomas are the most common type of anterior mediastinal germ cell tumor. Mature intrapericardial teratomas are generally diagnosed during infancy because of symptoms of cardiac compression. In contrast, mature adult intrapericardial teratomas are extremely rare, accounting for less than 1% of mature intrapericardial teratomas. We describe herein a case of a mature intrapericardial teratoma in an asymptomatic adult.Case presentationA 52-year-old woman was found by computed tomography during a health checkup to have an anterior mediastinal mass. She was asymptomatic and hemodynamically stable with no evidence of heart failure. The preoperative provisional radiological diagnosis was a mature intrapericardial teratoma. A median sternotomy revealed an approximately 5-cm diameter protruding intrapericardial mass with a smooth surface. The mass was completely resected. Histopathological examination resulted in a diagnosis of a mature intrapericardial teratoma. The patient did well and has no evidence of recurrence 5 years after surgery.ConclusionsMature intrapericardial teratomas in adults are extremely rare. Given the risks of malignant transformation, rupture, compression of the heart, and infection, excision is indicated to prevent development of serious manifestations.

P53 Overexpression May Represent an Early Marker of Clinicopathologic Progression in Vasculogenic Mesenchymal Lesions of Germ Cell Tumor Origin.

Vasculogenic mesenchymal lesions (VMLs) of germ cell tumor origin are thought to originate in postpubertal-type yolk sac tumor componentsand include a spectrum of lesions from teratoma with vasculogenic stroma (TVS), to low and high-grade vasculogenic mesenchymal tumors (VMTs). VMLs exhibit rudimentary to well-developed neoplastic vessels within primitive mesenchyme, being considered a neoplastic reiteration of embryonic vasculogenesis in the splanchnic mesoderm of the yolk sac. They occur in patients with primary mediastinal germ cell tumors after chemotherapy, and a subset progresses to "somatic-type" sarcomas [including angiosarcoma (AS)], with high-grade VMTs likely portending a higher risk. Recently, we encountered a low-grade VMT that progressed to metastatic AS during follow-up. In this case, both the low-grade VMT and the subsequent AS demonstrated p53 overexpression, suggesting that p53 alterations may precede histopathologic transformation. To test this hypothesis, we evaluated neoplasms representing the entire spectrum of VMLs using p53 immunohistochemistry (IHC; clone DO-7, Dako). Overexpression was defined as nuclear positivity in > 80% of neoplastic cells. Because the distinction between high-grade VMT and AS can be subjective in some cases, they were grouped together in a single category. Thirty-nine VMLs were assessed: 16 high-grade VMT/AS, 19 low-grade VMT, and 4 TVS. Patient age ranged from 19 to 46 years (mean, 30 years; male = 97%). Four high-grade VMT/AS and one low-grade VMT showed p53 overexpression (5/39 VMLs, 13%; 4/16 high-grade VMT/AS, 25%). These tumors included 1 unequivocal AS and 1 high-grade VMT/AS with progression to rhabdomyosarcoma. The only low-grade VMT with p53 overexpression demonstrated progression to AS. Another high-grade VMT that progressed to sarcoma demonstrated p53 overexpression in the sarcoma component, but it was excluded because the VMT was not represented in the material availableat the time of the study. Lesions with intratumoral grade heterogeneity (classified based the highest grade), demonstrated more pronounced p53 overexpression in the high-grade components. P53 overexpression is associated with disease progression in a subset of VMTs and may precede morphologic transformation to sarcoma. Routine evaluation of VMTs with p53 IHC seems justified, with overexpressors likely requiring an close clinical surveillance.

Malignant extracranial germ cell tumors in the Netherlands between 1990 and 2018: Stable incidence and improved survival

BackgroundPopulation-based studies assessing long-term patterns of incidence and disease characteristics of germ cell tumors (GCTs) in children are scarce. We investigated incidence and survival trends of malignant extracranial GCTs in children using population-based nationwide data from the Netherlands. MethodsAll malignant extracranial GCTs diagnosed in patients aged 0–18 years between 1990 and 2018 were selected from the Netherlands Cancer Registry. Incidence rates were calculated as the average annual number of cases per 1 million person-years. Five-year overall survival (OS) was calculated. ResultsA total of 815 cases were identified. Gonadal GCTs (n=665, testis n=485, ovarian n=180) were more common than extragonadal GCTs (n=149). Stage distribution for testicular and extragonadal GCTs shifted between 1990 and 2004 and 2005–2018 towards more localized disease. The overall incidence remained stable over time, but a significant increase was noted for extragonadal GCTs in the 0–9 years age group. Survival of extragonadal GCTs (5-year OS 84.1%, 95% CI 77.1–89.1), in particular mediastinal GCTs (5-year OS 66.7%, 95% CI 45.7–81.1), was lower than that of gonadal GCTs (5-year OS testis 95.0%, 95% CI 92.7–96.7;ovary 97.8%, 95% CI 94.2–99.2). The 5-year OS of our entire cohort was 93.6% (95% CI 91.7–95.1). Five-year OS significantly increased from 89.5% (95% CI 86.1–92.2) in 1990–2004–97.4% (95% CI 95.3–98.5) in 2005–2018. ConclusionsAlthough the incidence of all malignant pediatric extracranial GCTs remained stable during 1990–2018, an increase was observed for extragonadal GCTs in younger children (0–9 years). There was a shift towards more localized disease for testicular and extragonadal GCTs. Five-year OS increased over time exceeding 90% (91.4%, 95% CI 82.7–95.8) in the most recent diagnostic period. Mediastinal GCTs had the lowest OS, supporting the need for future research.

Surgical management of mediastinal mature cystic teratoma of the elderly remaining asymptomatic

BackgroundMediastinal teratoma is an uncommon disease, nevertheless they represent the most common mediastinal germ cell tumors. It may grow silently for several years and remain undiagnosed until the occurrence of a complication.AimThe main aim of this article is to illustrate the silent evolution of an anterior mediastinal teratoma for over 70 years without presenting any notable complications.Case presentationWe present the case of a 70-year-old female, treated for hypertension referred to our department for managing a voluminous mediastinal mass, discovered fortuitously by a general practitioner in a chest X-ray. The anamnesis didn’t relate any chest pain, cough, dyspnea nor hemoptysis. The clinical examination, in particular pleuropulmonary, was unremarkable. The workup (Chest X-Ray and CT scan) demonstrated a voluminous pleural mass at the expense of the right mediastinal pleura, rounded in shape, with calcified wall and fluid content. Blood tests did not demonstrate eosinophilia, and hydatid IgG serology was negative. serum human chorionic gonadotropin (hCG) and alpha fetoprotein (AFP) levels were found to be normal. The patient subsequently underwent a right posterolateral thoracotomy with resection of the lesion. The mass was dissected very carefully and then resected in toto. The macroscopic and microscopic histological examination demonstrated a mature cystic teratoma. Surgical resection was an adequate treatment and the prognosis was excellent for the patient.ConclusionCystic mature teratomas are rare thoracic tumors, often recognized by radiological examination. This article relates the silent evolution that a teratoma could have, and the late appearance of symptoms that it could have.

Diagnosis and management of mediastinal extragonadal germ cell tumors

SummaryExtragonadal germ cell tumors (EGCT) are rare and comprise only 2–3% of all testicular germ cell tumors. The majority of EGCT are located in the mediastinum, followed by the retroperitoneum. Although histologically similar to germ cell tumors (GCT), EGCT have distinct histological patterns which result in a biologically aggressive variant of GCT with the need for interdisciplinary care in highly specialized centers. The majority of mediastinal EGCT harbor teratoma or yolk sac tumor elements. Treatment usually consists of a combination of systemic cytotoxic therapy and aggressive postchemotherapeutic surgery. First-line treatment for extragonadal seminomas and nonseminomas consists of three and four cycles of PEB or PEI, respectively. In patients with significantly elevated markers, a personalized approach based on adequate marker decline can be used, and in poor-risk patients, first-line high-dose chemotherapy might be discussed. Postchemotherapeutic surgery remains an integral part of the multidisciplinary treatment for nonseminomatous EGCT and it is of utmost importance that all residual masses, independent of size and location, are resected completely. Residual masses in seminomatous EGCTs rarely harbor vital cancer and might be followed by serial imaging studies or FDG-PET/CT. The prognosis of nonseminomatous EGCT is poor, with 5‑year overall survival rates of 17%, 60–70%, and 90% for poor, intermediate, and excellent prognosis, respectively. Prognosis for seminomatous EGCT is excellent, with 5‑year overall survival rates of 95% and 88% for good and intermediate prognosis, respectively. Salvage chemotherapy consists of high-dose chemotherapy or targeted therapy in very selected patients.

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges.

This article will review current aspects of the histopathological, immunohistochemical and molecular analysis of primary mediastinal germ cell tumours (PMGCTs) as well as their aetiological, epidemiological, clinical and therapeutic features. PMGCTs represent an important differential diagnosis in the spectrum of mediastinal tumours, and their diagnosis is usually made on small tissue samples from core needle biopsies in combination with diagnostic imaging and serum tumour markers. As in lymphomas, a small biopsy is often the only viable tumour sample available from these patients, as they receive chemotherapy prior to eventual surgical resection. Pathologists therefore need to apply an efficient combination of immunohistochemical markers to confirm the diagnosis of a PMGCT and to exclude morphological mimics.

Successful surgical treatment of chemoresistant mediastinal germ cell tumor

Mediastinal teratoma is a rare germ cell tumor. The mediastinum is the most common extragonadal site. Malignant tumors of the mediastinum account for 4 % of all extragonadal tumors of the mediastinum. We present a case of successful surgical treatment of a 24‑year-old man with a gigantic immature mediastinal teratoma complicated by severe cardiorespiratory disorders.

Comments on the publication of Khakimov G. A. et al. “Successful surgical treatment of chemoresistant mediastinal germ cell tumor”

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MO42-6 Analysis of sperm preservation in patients with mediastinal germ cell tumor patients

MO42-6 Analysis of sperm preservation in patients with mediastinal germ cell tumor patients

Second Hematologic Malignancies Associated With Primary Mediastinal Germ Cell Tumors: A Population-based Study.

Studies addressing second hematologic malignancies (SHMs) in patients with primary mediastinal germ cell tumors (PMGCTs) are scarce. To better describe this phenomenon, we analyzed a large case series from a population-based registry. The Surveillance, Epidemiology, and End Results database was used to report the clinical characteristics and incidence of SHMs in patients with PMGCT. Among 1297 PMGCTs, 27 cases (2.08%) of SHM were found, with a median latency period of 12 months (95% CI: 5-41). All SHM occurred in males, 20 of whom (74.1%) had a previous nonseminomatous tumor. Acute myeloid leukemia was the most frequent SHM, accounting for 13 cases, 4 of which were acute megakaryoblastic leukemia that occurred within 5 months of diagnosis. The median survival after the diagnosis of SHM was 6 months (95% CI: 2-41). The risk of SHM was significantly higher than expected for the reference population, with a standardized incidence ratio of 6.21 (95% CI: 3.31-10.62) and an absolute excess risk of 19.19 per 10,000 person-years. Patients with PMGCT are at a higher risk of developing SHMs than the general population, particularly acute myeloid leukemia. This risk ranges from synchronous diagnosis of acute megakaryoblastic leukemia to the later onset of other hematological disorders that might be related to PMGCT therapies. Our findings may help create follow-up schedules for patients with PMGCT and raise the level of suspicion surrounding this association.

18F]fluorodeoxyglucose positron emission tomography/computed tomography characteristics of primary mediastinal germ cell tumors

Primary mediastinal germ cell tumor (MGCT) is an uncommon tumor. Although it has histology similar to that of gonadal germ cell tumor (GCT), the prognosis for MGCT is generally worse than that for gonadal GCT. We performed visual assessment and quantitative analysis of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) for MGCTs. A total of 35 MGCT patients (age = 33.1 ± 16.8 years, F:M = 16:19) who underwent preoperative PET/CT were retrospectively reviewed. The pathologic diagnosis of MGCTs identified 24 mature teratomas, 4 seminomas, 5 yolk sac tumors, and 2 mixed germ cell tumors. Visual assessment was performed by categorizing the uptake intensity, distribution, and contour of primary MGCTs. Quantitative parameters including the maximum standardized uptake value (SUVmax), tumor-to-background ratio (TBR), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum diameter were compared between benign and malignant MGCTs. On visual assessment, the uptake intensity was the only significant parameter for differentiating between benign and malignant MGCTs (p = 0.040). In quantitative analysis, the SUVmax (p < 0.001), TBR (p < 0.001), MTV (p = 0.033), and TLG (p < 0.001) showed significantly higher values for malignant MGCTs compared with benign MGCTs. In receiver operating characteristic (ROC) curve analysis of these quantitative parameters, the SUVmax had the highest area under the curve (AUC) (AUC = 0.947, p < 0.001). Furthermore, the SUVmax could differentiate between seminomas and nonseminomatous germ cell tumors (p = 0.042) and reflect serum alpha fetoprotein (AFP) levels (p = 0.012). The visual uptake intensity and SUVmax on [18F]FDG PET/CT showed discriminative ability for benign and malignant MGCTs. Moreover, the SUVmax may associate with AFP levels.

Malignant Teratoma Arising From Mediastinal Non-Seminomatous Germ Cell Tumor: A Rare Case Report

Introduction: Primary mediastinal non-seminomatous germ cell tumors (NSGCT) have a worse prognosis than gonadal germ cell tumors (GCTs). Malignant transformation of teratomatous components of GCT to a somatic malignancy is rare.&#x0D; Materials and methods: A case of primary mediastinal NSGCT with malignant transformation of a teratoma was seen in a 23 years old male. Resected tumor specimen was received. Tissue processing was done and sections were prepared for Histo Pathological Examination.&#x0D; Results: Histopathology confirmed NSGCT with yolk sac and teratomatous components. Chemotherapy for GCT transiently normalized serum tumor markers with little effect on the mediastinal mass. Incomplete resection of the residual tumor revealed intermediate grade chondosarcoma. Here we discuss this rare case.&#x0D; Conclusion: malignant transformation to chondrosarcoma is a rare possibility which needs to be considered while managing the patient of Primary Mediastinal Germ Cell Tumors (PMGCT)

Analysis of prognostic factors and establishment of prognostic model for primary mediastinal germ cell tumors: a case controlled study.

The overall prognosis of primary mediastinal germ cell tumors (PMGCTs) is poor and the associated prognostic factors are not fully understood. Our goal was to investigate the prognostic factors of PMGCTs and to develop a validated prognostic prediction model. A total of 114 PMGCTs with specific pathological types were included in this study. Clinicopathological characteristics of nonseminomatous PMGCTs and mediastinal seminomas were compared using the χ2 or Fisher's exact test. Independent prognostic factors of nonseminomatous PMGCTs screened using the univariate and multivariate Cox regression analysis were then used to generate a nomogram. The predictive performance of the nomogram was evaluated using the concordance index, decision curve, and the area under the receiver operating characteristic curve (AUC) and validated by bootstrap resampling. The Kaplan-Meier curves of independent prognostic factors were analyzed. This study included 71 cases of nonseminomatous PMGCTs and 43 cases of mediastinal seminomas. The 3-year overall survival rates for nonseminomatous PMGCTs and mediastinal seminomas patients were 54.5 and 97.4%, respectively. The overall survival prognostic nomogram for nonseminomatous PMGCTs was established by integrating independent prognostic factors, including the Moran-Suster stage, white blood cell, hemoglobin, and platelet-lymphocyte ratio. The nomogram demonstrated good performance with a concordance index of 0.760 and the 1-year and 3-year AUC values of 0.821 and 0.833, respectively. These values were better than those of the Moran-Suster stage system. The bootstrap validation had an AUC of 0.820 (0.724-0.915) and showed a well-fitting calibration curve. Besides, patients with mediastinal seminomas showed favorable clinical outcomes and all the nine patients received neoadjuvant therapy and postoperative surgery achieved pathological complete response. A nomogram based on staging and blood routine examination results was established to accurately and consistently predict the prognosis of patients with nonseminomatous PMGCTs.

Gene mutation landscape of a rare patient with acute megakaryoblastic leukemia after treatment of intracranial germ cell tumor.

It was first reported that germ cell tumor patients suffer from hematologic malignancies 37 years ago. Since then, the number of relevant reports has increased each year, with most cases being mediastinal germ cell tumor. Theories have been proposed to explain this phenomenon, including a shared origin of progenitor cells, the effects of treatment, and independent development. However, up to now, no widely accepted explanation exists. The case with acute megakaryoblastic leukemia and intracranial germ cell tumor has never been reported before and the association is far less known. We used whole exome sequencing and gene mutation analysis to study the relationship between intracranial germ cell tumor and acute megakaryoblastic leukemia of our patient. We report a patient who developed acute megakaryoblastic leukemia after treatment for an intracranial germ cell tumor. Through whole exome sequencing and gene mutation analysis, we identified that both tumors shared the same mutation genes and mutation sites, suggesting they originated from the same progenitor cells and differentiated in the later stage. Our findings provide the first evidence supporting the theory that acute megakaryoblastic leukemia and intracranial germ cell tumor has the same progenitor cells.

Clinical Features and Survival Outcomes in Children and Adolescents With Malignant Mediastinal Germ Cell Tumors Based on Surveillance, Epidemiology, and End Results Database Analysis

IntroductionThe purpose of this study was to perform a population-based investigation to assess the disease characteristics and prognosis of children and adolescents with malignant mediastinal germ cell tumors (MMGCT). MethodsData on the demographics, treatment, and survival outcomes of children and adolescents with MMGCT from January 1, 2000 to December 31, 2018 were obtained. To compare survival curves, the log-rank test was employed. The generation of survival curves based on different parameters was done using Kaplan–Meier estimations. Cox proportional hazards regression was performed to determine the variables linked to disease-specific survival. ResultsThe selection criteria were met by 152 MMGCT patients, 130 of whom were male. Fifty three cases of mixed germ cell tumors (GCTs), 41 cases of malignant teratomas, 26 cases of yolk sac tumors, 14 cases of seminoma, 13 cases of choriocarcinomas, and five cases of embryonal carcinoma were reported. Overall survival at 3 and 5 y for all patients was 63.1% and 61.2%, respectively. Malignant teratoma, yolk sac tumors, and mixed GCTs in children and adolescents had comparable survival rates, while those with choriocarcinoma and embryonal carcinoma showed the worst prognosis. Embryonal carcinoma, malignant teratoma, mixed GCTs, and choriocarcinoma were found as risk factors by multivariate Cox proportional hazards analysis. In contrast, surgery and younger age were protective factors. However, chemotherapy alone showed no survival benefits. ConclusionsOur population-based evidence showed that MMGCT had worse prognosis in older children and adolescents. Choriocarcinomas and embryonal carcinomas had the worst prognosis. Surgery can prolong survival time. Chemotherapy and radiotherapy were not associated with improved prognosis.