Paediatric extracranial germ-cell tumours

Staging and Restaging Pediatric Abdominal and Pelvic Tumors: A Practical Guide

The most common abdominal malignancies diagnosed in the pediatric population include neuroblastoma, Wilms tumor, hepatoblastoma, lymphoma, germ cell tumor, and rhabdomyosarcoma. There are distinctive imaging findings and patterns of spread for each of these tumors that radiologists must know for diagnosis and staging and for monitoring the patient's response to treatment. The multidisciplinary treatment group that includes oncologists, surgeons, and radiation oncologists relies heavily on imaging evaluation to identify the best treatment course and prognostication of imaging findings, such as the image-defined risk factors for neuroblastomas, the PRETreatment EXtent of Disease staging system for hepatoblastoma, and the Ann Arbor staging system for lymphomas. It is imperative for radiologists to be able to correctly indicate the best imaging methods for diagnosis, staging, and restaging of each of these most prevalent tumors to avoid inconclusive or unnecessary examinations. The authors review in a practical manner the most updated key points in diagnosing and staging disease and assessing response to treatment of the most common pediatric abdominal tumors. ©RSNA, 2024 Supplemental material is available for this article.

A comprehensive population-based study of malignant ovarian tumors, including histologic and immunohistochemical review, in children and adolescents 0-19 years old in Sweden between 1970 and 2014

OBJECTIVES

Ovarian tumors in the pediatric population are rare. The incidence and frequency of subtypes differ between children and adults. Although not all tumors are aggressive, they may still lead to morbidity. The goal of this study was a comprehensive review of malignant ovarian tumors in children and adolescents diagnosed and registered in Sweden.

METHODS

Individuals were identified through a search in the National Cancer Register, limited for ages 0-19, years 1970-2014. Stored tumor diagnostic material from regional biobanks was retrieved and reviewed.

RESULTS

The study includes 345 individuals with ovarian tumors and 70.7% of them were between 15 and 19 years at time of diagnosis. No differences in incidence over time or geographic location were identified. The average follow-up time was 21.2 years and 5-year survival was 88.4%. Survival was similar in the different time periods, except for 1970-1979. Review was possible for 260 cases, resulting in 85 epithelial tumors, 121 GCTs, 47 SCSTs and 7 others. For age 0-4 years SCSTs dominated (85.7%), for 5-9- and 10-14-years GCTs dominated (70,8% and 75.0% respectively), and for age 15-19 years epithelial tumors dominated (43.8%). There was a strong agreement between review diagnosis and original diagnosis (Cohen's κ 0.944). Differentiating between entities within the sex cord-stromal group posed the biggest diagnostic challenge.

CONCLUSIONS

Ovarian tumors in children and adolescents are rare and distinct from their adult counterparts regarding incidence and frequency. There was a strong concurrence between original and review diagnoses. The greatest diagnostic difficulty was subtyping of epithelial tumors and differentiating between tumors within the SCST group.

Outcomes of pediatric extracranial germ cell tumors: A single center experience in a developing country

The purpose of this study was to analyze the outcomes of extracranial GCT in children in a developing country and to assess prognostic factors. The data on 141 children (<18 years old) with extracranial GCT, confirmed histopathologically, collected over the past 9 years (from February 2013 to June 2022) were retrospectively studied. The patients underwent the same therapy with platinum-containing chemotherapy regimens. In the malignant GCT group, OS and EFS were 81.0 ± 4% and 73 ± 5%, respectively. OS and EFS in the teratoma group were 90 ± 5% and 85 ± 6%. In univariate analysis, parameters like stage of disease, tumor localization, AFP level ≥10,000 ng/mL, serum AFP kinetics and resection status were found to be statistically significant prognostic factors. In the multivariate analysis, the significant adverse factors were the resection status, initial AFP level ≥10,000 ng/mL and serum AFP kinetics slow down (p = .000). Good survival rates can be achieved in developing countries with adequate compliance with treatment protocols. The analysis demonstrates high efficacy of platinum-containing chemotherapy regimens. In our opinion, the protocol used in high-income countries can be implemented in low-income countries with the financial support from the government. The qualification of specialists is also important.

Mediastinal Germ-cell Tumors Relapse in a Male With Klinefelter Syndrome. Is Longer Surveillance Needed?

Germ cell tumors (GCTs) are a heterogeneous group of pediatric cancers. In up to one-third of male patients, a primary mediastinal location is associated with the presence of Klinefelter syndrome (KS). We describe a case of mediastinal GCT in a patient, with unacknowledged KS, that presented a relapse 7 years from diagnosis, that is, 2 years after the end of the follow-up program usually recommended for patients with GCT. There are no recommendations for screening for KS in patients with mediastinal GCT and there are no specific guidelines for surveillance of GCT in KS patients. Our experience suggests that KS should be suspected in patients with mediastinal GCT, and a longer follow-up plan should be implemented when GCT occurs in patients with KS.

Germ Cell Tumor of the Yolk Sac in the Uterine Corpus: Case Report of a 14-Month-Old Female Infant

Malignant germ cell tumors (MGCTs) localized in the uterus are rare in prepubertal girls. They typically occur in postmenopausal women and are characterized by the presence of a pelvic mass and transvaginal bleeding. In this case, the authors describe the clinical features, radiologic findings, histopathologic description, and treatment received by an infant with a primary yolk sac tumor of the uterine wall. Currently, treatment for uterine GCTs is based on guidelines for GCTs. Surgery and bleomycin, etoposide, cisplatin (pBEP) chemotherapy are effective for uterine yolk sac tumors. After 46 months of clinical follow-up, which included abdominopelvic ultrasound and tumor marker assessments, our patient is free of disease, suggesting a favorable outcome.

Extracranial Germ Cell Tumors in Children: Ten Years of Experience in Three Children's Medical Centers in Shanghai

OBJECTIVE

The aim was to describe the clinical features of extracranial germ cell tumors (GCTs) in pediatrics and study the clinical risk factors related to survival for malignant germ cell tumors (MGCTs) in order to optimize therapeutic options.

METHODS

The clinical data of children with extracranial GCTs in three children's medical centers in Shanghai were retrospectively analyzed.

RESULTS

In total, 1007 cases of extracranial GCTs diagnosed between 2010 and 2019 were included in this study, including teratomas (TERs) 706 (70.11%) and MGCTs 301 (29.89%). There were twice as many TER cases as MGCT cases. Approximately 50% of children with GCTs were <3 years old (43.39% for TERs, 67.13% for MGCTs). GCTs in children of different ages show differences in tumor anatomical locations and pathological subtypes. The 5-year event-free survival (EFS) and overall survival (OS) of all patients with MGCTs were 82.33% (95% CI, 77.32%, 86.62%) and 94.13% (95% CI, 90.02%, 96.69%), respectively. The multivariate Cox regression analysis identified a primary site in the mediastinum and alpha fetoprotein (AFP) levels ≥10,000 ng/mL as independent adverse prognostic factors (p < 0.0.0001, χ2 = 23.6638, p = 0.0225, χ2 = 5.2072.). There were no significant differences in OS among children receiving various chemotherapy regimens, such as the BEP, PEB, JEB and other regimens (VBP/VIP and AVCP/IEV) (p < 0.05).

CONCLUSIONS

The clinical features of GCTs in Chinese pediatrics are similar to those reported in children in Europe and America. The age distribution of pathological types and primary sites in GCTs reflect the developmental origin of type I and type II GCTs transformed from mismigration primordial germ cells (PGCs). Optimizing the current platinum-based chemotherapy regimens and exploring the treatment strategies for MGCTs of the mediastinum are future research directions.

Associations between birth defects and childhood and adolescent germ cell tumors according to sex, histologic subtype, and site

BACKGROUND

Studies have reported increased rates of birth defects among children with germ cell tumors (GCTs). However, few studies have evaluated associations by sex, type of defect, or tumor characteristics.

METHODS

Birth defect-GCT associations were evaluated among pediatric patients (N = 552) with GCTs enrolled in the Germ Cell Tumor Epidemiology Study and population-based controls (N = 6380) without cancer from the Genetic Overlap Between Anomalies and Cancer in Kids Study. The odds ratio (OR) and 95% confidence interval (CI) of GCTs according to birth defects status were estimated by using unconditional logistic regression. All defects were considered collectively and by genetic and chromosomal syndromes and nonsyndromic defects. Stratification was by sex, tumor histology (yolk sac tumor, teratoma, germinoma, and mixed/other), and location (gonadal, extragonadal, and intracranial).

RESULTS

Birth defects and syndromic defects were more common among GCT cases than controls (6.9% vs. 4.0% and 2.7% vs. 0.2%, respectively; both p < .001). In multivariable models, GCT risk was increased among children with birth defects (OR, 1.7; 95% CI, 1.3-2.4) and syndromic defects (OR, 10.4; 95% CI, 4.9-22.1). When stratified by tumor characteristics, birth defects were associated with yolk sac tumors (OR, 2.7; 95% CI, 1.3-5.0) and mixed/other histologies (OR, 2.1; 95% CI, 1.2-3.5) and both gonadal tumors (OR, 1.7; 95% CI, 1.0-2.7) and extragonadal tumors (OR, 3.8; 95% CI, 2.1-6.5). Nonsyndromic defects specifically were not associated with GCTs. In sex-stratified analyses, associations were observed among males but not females.

CONCLUSIONS

These data suggest that males with syndromic birth defects are at an increased risk of pediatric GCTs, whereas males with nonsyndromic defects and females are not at an increased risk.

PLAIN LANGUAGE SUMMARY

We investigated whether birth defects (such as congenital heart disease or Down syndrome) are linked to childhood germ cell tumors (GCTs), cancers that mainly develop in the ovaries or testes. We studied different types of birth defects (defects that were caused by chromosome changes such as Down syndrome or Klinefelter syndrome and defects that were not) and different types of GCTs. Only chromosome changes such as Down syndrome or Klinefelter syndrome were linked to GCTs. Our study suggests that most children with birth defects are not at an increased risk of GCTs because most birth defects are not caused by chromosome changes.

Critical elements in the operative management of pediatric malignant ovarian germ cell tumors

Performance of the appropriate operation is highly important to ensure that any patient with a suspected ovarian germ cell tumor receives optimal therapy that prioritizes cure while simultaneoulsy minimizing risk of short and long-term toxicities of treatment. The following critical elements of any operative procedure performed for a suspected pediatric or adolescent ovarian germ cell tumor are reviewed: 1. Complete resection of the tumor via ipsilateral oophorectomy while avoiding tumor rupture and spillage, and 2. Performance of complete intraperitoneal staging at the time of initial tumor resection.

Children's Oncology Group's 2023 blueprint for research: Germ cell tumors

Extracranial germ cell tumors (GCT) are a biologically diverse group of tumors occurring in children, adolescents, and young adults. The majority of patients have excellent outcomes, but treatment-related toxicities impact their quality of survivorship. A subset of patients succumbs to the disease. Current unmet needs include clarifying which patients can be safely observed after initial surgical resection, refinement of risk stratification to reduce chemotherapy burden in patients with standard-risk disease, and intensify therapy for patients with poor-risk disease. Furthermore, enhancing strategies for detection of minimal residual disease and early detection of relapse, particularly in serum tumor marker-negative histologies, is critical. Improving the understanding of the developmental and molecular origins of GCTs may facilitate discovery of novel targets. Future efforts should be directed toward assessing novel therapies in a biology-driven, biomarker-defined, histology-specific, risk-stratified patient population. Fragmentation of care between subspecialists restricts the unified study of these rare tumors. It is imperative that trials be conducted in collaboration with national and international cooperative groups, with harmonized data and biospecimen collection. Key priorities for the Children's Oncology Group (COG) GCT Committee include (a) better understanding the biology of GCTs, with a focus on molecular targets and mechanisms of treatment resistance; (b) strategic development of pediatric and young adult clinical trials; (c) understanding late effects of therapy and identifying individuals most at risk; and (d) prioritizing diversity, equity, and inclusion to reduce cancer health disparities and studying the impacts of social determinants of health on outcomes.

Case series on clinical applications of liquid biopsy in pediatric solid tumors: towards improved diagnostics and disease monitoring

Background and aims

Solid tumors account for about 30% of all pediatric cancers. The diagnosis is typically based on histological and molecular analysis of a primary tumor biopsy. Liquid biopsies carry several advantages over conventional tissue biopsy. However, their use for genomic analysis and response monitoring of pediatric solid tumors is still in experimental stages and mostly performed retrospectively without direct impact on patient management. In this case series we discuss six clinical cases of children with a solid tumor for whom a liquid biopsy assay was performed and demonstrate the potential of liquid biopsy for future clinical decision making.

Methods

We performed quantitative real-time PCR (RT-qPCR), droplet digital PCR (ddPCR) or reduced representation bisulphite sequencing of cell-free DNA (cfRRBS) on liquid biopsies collected from six pediatric patients with a solid tumor treated between 2017 and 2023 at the Princess Máxima Center for Pediatric Oncology in the Netherlands. Results were used to aid in clinical decision making by contribution to establish a diagnosis, by prognostication and response to therapy monitoring.

Results

In three patients cfRRBS helped to establish the diagnosis of a rhabdomyosarcoma, an Ewing sarcoma and a neuroblastoma (case 1-3). In two patients, liquid biopsies were used for prognostication, by MYCN ddPCR in a patient with neuroblastoma and by RT-qPCR testing rhabdomyosarcoma-specific mRNA in bone marrow of a patient with a rhabdomyosarcoma (case 4 and 5). In case 6, mRNA testing demonstrated disease progression and assisted clinical decision making.

Conclusion

This case series illustrates the value of liquid biopsy. We further demonstrate and recommend the use of liquid biopsies to be used in conjunction with conventional methods for the determination of metastatic status, prognostication and monitoring of treatment response in patients with pediatric solid tumors.

Molecular Biology of Pediatric and Adult Ovarian Germ Cell Tumors: A Review

Ovarian germ cell tumors (OGCTs) are rare in adults; indeed, they occur predominantly in children, adolescents, and young adults, and they account for approximately 11% of cancer diagnoses in these groups. Because OGCTs are rare tumors, our current understanding of them is sparse; this is because few studies have investigated the molecular basis of pediatric and adult cancers. Here, we review the etiopathogenesis of OGCTs in children and adults, and we address the molecular landscape of these tumors, including integrated genomic analysis, microRNAs, DNA methylation, the molecular implications of treatment resistance, and the development of in vitro and in vivo models. An elucidation of potential molecular alterations may provide a novel field for understanding the pathogenesis, tumorigenesis, diagnostic markers, and genetic peculiarity of the rarity and complexity of OGCTs.

A case series and literature review on 98 pediatric patients of germ cell tumor developing growing teratoma syndrome

INTRODUCTION

Malignant germ cell tumors (MGCTs) can develop either extracranially or intracranially. Growing teratoma syndrome (GTS) may develop in these patients following chemotherapy. Reports on the clinical characteristics and outcomes of GTS in children with MGCTs are limited.

METHODS

We retrospectively collected the data, including the clinical characteristics and outcomes of five patients in our series and 93 pediatric patients selected through a literature review of MGCTs. This study aimed to analyze survival outcomes and risk factors for subsequent events in pediatric patients with MGCTs developing GTS.

RESULTS

The sex ratio was 1.09 (male/female). In total, 52 patients (53.1%) had intracranial MGCTs. Compared with patients with extracranial GCTs, those with intracranial GCTs were younger, predominantly boys, had shorter intervals between MGCT and GTS, and had GTS mostly occurring over the initial site (all p < 0.001). Ninety-five patients (96.9%) were alive. However, GTS recurrence (n = 14), GTS progression (n = 9), and MGCT recurrence (n = 19) caused a substantial decrease in event-free survival (EFS). Multivariate analyses showed that the only significant risk factors for these events were incomplete GTS resection and different locations of GCT and GTS. Patients without any risk had a 5-year EFS of 78.8% ± 7.8%, whereas those with either risk had 41.7% ± 10.2% (p < 0.001).

CONCLUSION

For patients with high-risk features, every effort should be made to closely monitor, completely remove, and pathologically prove any newly developed mass to guide relevant treatment. Further studies incorporating the risk factors into treatment strategies may be required to optimize adjuvant therapy.

Pediatric Extracranial Germ Cell Tumors: Review of Clinics and Perspectives in Application of Autologous Stem Cell Transplantation

Pediatric extracranial germ cell tumors (GCTs) are rare, accounting for approximately 3.5% of childhood cancers. Since the introduction of platinum-based chemotherapy, the survival rate of patients has improved to more than 80%. However, poor-risk subtypes of pediatric extracranial GCTs do not respond well to chemotherapy, leading to refractory or relapsed (R/R) diseases. For example, long-term survival rates of mediastinal GCTs or choriocarcinoma are less than 50%. According to reports in recent years for adult patients with R/R GCTs, the use of high-dose chemotherapy (HDCT) combined with autologous stem cell transplantation (ASCT) has clinical advantages; however, HDCT combined with ASCT has rarely been reported in pediatric GCTs. The R/R and poor-risk groups of pediatric GCTs could benefit from HDCT and ASCT.

Ovarian yolk sac tumor in a premenarchal girl

Yolk sac tumors are highly malignant and commonly affect the ovaries, with a median age of occurrence of 23 years. We describe the case of an ovarian yolk sac tumor in a 12-year-old premenarchal girl suffering from Hashimoto's thyroiditis and chronic spontaneous urticaria, which presented as a rapidly growing solid cystic formation in the hypogastrium with an extreme increase in alpha fetoprotein (52,778 mg/ml). After ultrasound and MRI imaging, fertility-sparing staging surgery was performed, and the diagnosis of an ovarian yolk sac tumor with positive malignant cells in ascites was confirmed. The specificity of this case is the tumor classification into stage IC3 according to the FIGO and stage III according to the Children's Oncology Group criteria. The postoperative course was complicated by a pelvic abscess and a subcutaneous suture rejection reaction. Our case may incite further research on the relationship between autoimmunity and yolk sac tumors.

Pediatric Extracranial Germ Cell Tumors: Expression of microRNA

BACKGROUND

Germ cell tumors (GCTs) may occur from the neonatal period to late adulthood, characterized by extensive clinical and pathologic heterogeneity. MicroRNAs are a family of small noncoding RNAs that regulate a wide array of biological processes including carcinogenesis. MicroRNAs may be used for many purposes in clinical diagnostics. Numerous studies have proven the diagnostic value of microRNA371-373 and microRNA302/367 expression in malignant GCT. The diagnostic value of microRNA375 is disputable, because while its value is confirmed by some research data, there are still others denying it.

METHODS

The results of our own research on the relative expression of 10 microRNAs, including microRNA375, associated with GCT in the tumor tissues of 84 children and adolescents are presented.

RESULTS

In our research, overexpression of microRNA 371-373, 302/367 detected in the group of malignant GCT subtypes. Statistically significant expression of microRNA375 have been defined not only in the group of malignant GCT subtypes, but also in the group of immature teratomas. Among malignant GCTs, high expression of microRNA375 is specific for yolk sac tumors. In the group of seminomas, embryonic carcinomas, and mature teratomas expression of microRNA375 was observed imperceptible, even so the results were statistically insignificant.

CONCLUSION

Expression of microRNA 371-373, 302/367 is representative of malignant GCT subtypes. Statistically significant and high expression of microRNA375 attributable for yolk sac tumors and immature teratomas.

P B, Ramadwar M, Singh S, Shukla A, Panwala H, Sahu A, Siddharth L, Kapadia T. Imaging Recommendations for Diagnosis, Staging, and Management of Pediatric Solid Tumors

Paediatric extra-cranial solid tumours are one of the common causes for paediatric malignancies. Lack of appropriate imaging at presentation, staging and for follow-up is a major challenge for paediatric solid tumours. We have reviewed the paediatric solid tumour imaging protocols suggested by the major oncological societies/groups around the world (mainly the SIOP – Society International Pediatric Oncology, and the COG – Children's Oncology Group). We have adapted some of those protocols to develop imaging recommendations for the diagnosis, staging and management of extra-cranial solid tumours based on the treatment protocols followed in India.

Advancing clinical and translational research in germ cell tumours (GCT): recommendations from the Malignant Germ Cell International Consortium

Germ cell tumours (GCTs) are a heterogeneous group of rare neoplasms that present in different anatomical sites and across a wide spectrum of patient ages from birth through to adulthood. Once these strata are applied, cohort numbers become modest, hindering inferences regarding management and therapeutic advances. Moreover, patients with GCTs are treated by different medical professionals including paediatric oncologists, neuro-oncologists, medical oncologists, neurosurgeons, gynaecological oncologists, surgeons, and urologists. Silos of care have thus formed, further hampering knowledge dissemination between specialists. Dedicated biobank specimen collection is therefore critical to foster continuous growth in our understanding of similarities and differences by age, gender, and site, particularly for rare cancers such as GCTs. Here, the Malignant Germ Cell International Consortium provides a framework to create a sustainable, global research infrastructure that facilitates acquisition of tissue and liquid biopsies together with matched clinical data sets that reflect the diversity of GCTs. Such an effort would create an invaluable repository of clinical and biological data which can underpin international collaborations that span professional boundaries, translate into clinical practice, and ultimately impact patient outcomes.

Sacrococcygeal Yolk Sac Tumor in a Two-Year-Old Girl With Multiple Metastases: A Case Report

Sacrococcygeal yolk sac tumor (YST) is an infrequent extra-gonadal malignant germ cell tumor (GCT) that occurs exclusively within the first two years of life. A two-year-old girl came with a massive mass on her left buttock, which continued to grow, and within three months had become extremely large and hindered her from walking. Physical examination revealed a sacrococcygeal mass of 15 cm in diameter. Multislice CT showed an intraluminal inferior cava vein mass extending into the pelvic cavity with coccygeal osseous destruction, pulmonary metastasis, and multiple hepatic metastases. Laboratory data revealed elevated tumor marker values for alpha-feto-protein (AFP), lactate dehydrogenase (LDH), and Ca-125. Cytopathology following fine needle aspiration biopsy evaluation of the smear sample revealed a cellular tumor with pseudo glandular, microcystic, and solid patterns. The cytopathology did not show pathognomic findings. An immunocytochemistry (IHC) examination of the cell block showed a positive result for anti-AFP antibody. The patient was diagnosed and treated with chemotherapy for a sacrococcygeal YST. Clinical follow-up on the fourth month showed that the tumor had shrunk to 4 cm in size. Laboratory follow-up data after four months showed significant improvement. Unfortunately, the patient passed away on the seventh cycle of chemotherapy due to lung and hepatic metastases.

Clonal diversification and histogenesis of malignant germ cell tumours

Germ cell tumours (GCTs) are a collection of benign and malignant neoplasms derived from primordial germ cells. They are uniquely able to recapitulate embryonic and extraembryonic tissues, which carries prognostic and therapeutic significance. The developmental pathways underpinning GCT initiation and histogenesis are incompletely understood. Here, we study the relationship of histogenesis and clonal diversification in GCTs by analysing the genomes and transcriptomes of 547 microdissected histological units. We find no correlation between genomic and histological heterogeneity. However, we identify unifying features including the retention of fetal developmental transcripts across tissues, expression changes on chromosome 12p, and a conserved somatic evolutionary sequence of whole genome duplication followed by clonal diversification. While this pattern is preserved across all GCTs, the developmental timing of the duplication varies between prepubertal and postpubertal cases. In addition, tumours of younger children exhibit distinct substitution signatures which may lend themselves as potential biomarkers for risk stratification. Our findings portray the extensive diversification of GCT tissues and genetic subclones as randomly distributed, while identifying overarching transcriptional and genomic features.

Yolk sac tumours of the orbit and sinonasal tract

PURPOSE

The aim of this study is to report two cases of paediatric Yolk sac tumours (YST) of the orbit and sinonasal tract, with a major review on the subject.

METHODS

Two case reports along with a comprehensive retrospective literature review of all English language publications between 1974 and 2021 is presented. Literature review examined the demographics, clinical presentation and diagnostic and prognostic factors of extragonadal YSTs of the orbit and sinonasal tract.

RESULTS

Orbit and sinuses are rare sites for YST, with only 25 paediatric cases reported in the literature. Extragonadal yolk sac tumours carry a significantly worse outcome than those localised to the gonads, with the 5-year survival of 66% and 81-89%, respectively. Our review found the median age of presentation to be 18 months (18 months for males and 24 months for females), and females are more commonly affected. The most common presentations were proptosis, facial swelling and ophthalmoplegia. Treatments and therefore outcomes varied in the cases due to the large time period. Of the cases reported in the last 10 years, all patients with data provided were alive and disease-free at follow-up.

CONCLUSION

Sino-orbital yolk sac tumours are rare and have variable presentations, dependent on the extent of local invasion. Early diagnosis and treatment with multimodal therapy are paramount in having improved overall survival.

Giant malignant sacrococcygeal germ cell tumor in a newborn: A rare case report

Malignant germ cell tumors constitute about 3%-4% of all neoplasms occurring before the age of 15. They arise in the ovaries, the testes, and in several other locations, including the lower back, the chest, the brain, and the abdomen. In infants and young children, the sacrococcygeal region is the most common site for extragonadal germ cell tumors, and teratomas account for the vast majority of sacrococcygeal germ cell tumors. Neonatal sacrococcygeal teratomas are usually benign and rarely they may contain a malignant component that is predominantly a yolk sac tumor. In this article, we describe a rare case of a male newborn with a giant sacrococcygeal mixed germ cell tumor composed of grade 3 immature teratoma and malignant yolk sac elements.

Outcomes and prognostic variables of extracranial germ cell tumors in children and adolescents treated over a decade: A developing world perspective

BACKGROUND

The purpose of this single-center study was to analyze the outcomes of extracranial germ cell tumors (GCTs) in children treated on a multimodality regimen.

METHODS

Retrospective study of children (<18 years) with a histopathologically confirmed diagnosis of extracranial GCT over a period of 10 years (January 2009 to December 2018) treated on a uniform institution-based protocol consisting of both cisplatin- and carboplatin-based regimens. All completely excised teratomas and stage I gonadal tumors received no further therapy (low risk [LR]); stage IV ovarian, stage III-IV extragonadal GCTs received six cycles of chemotherapy (high risk [HR]), and the remaining received four cycles of chemotherapy (intermediate risk [IR]).

RESULTS

A total of 297 children were treated with a female:male ratio of 1.72:1 and median age of 4 years. Forty-three children had pure teratomas. Gonadal GCTs (N = 180) were more common than extragonadal GCTs (N = 117) with ovary as primary site in 128 children (43%) and sacrococcygeal site being the commonest extragonadal location (N = 41; 14%). LR, IR, and HR disease were noted in 60 (20.2%), 125 (42%), and 112 (37.8%) patients, respectively. Three-fourths of ovarian tumors and half of testicular tumors operated prior to presentation needed upstaging. Forty-one patients relapsed and 43 children expired (disease-related: 33; toxic deaths: 9; unknown: 1). The 5-year event-free survival (EFS)/overall survival (OS) of malignant GCT (n = 254) was 72.50%/82.70%, respectively, with gonadal site (p = .001), LR and IR (p = .001) and nonmetastatic disease (p = .001) being favorable prognostic variables.

CONCLUSIONS

The LR and IR GCTs in our cohort had an excellent outcome. A significant proportion of IR gonadal GCTs can be spared of systemic chemotherapy by adhering to strict surgical guidelines. In HR GCTs however, intensifying therapies to improve outcomes must be balanced against the risk of cumulative toxicity, more so in a resource-limited setting.

Yolk sac tumor of the uterus in a 2-year-old girl: A case report and literature review

BACKGROUND

Extragonadal yolk sac tumors (YSTs) occurring in the uterus are extremely rare. To report a uterine YST case in a prepubertal girl and review literature on uterine YST to outline clinical management in diagnosis and treatment.

CASE

We present a case of a 2-year-old girl who presented with vaginal bleeding and a pelvic mass. The diagnosis of YST was confirmed via biopsy. After four cycles of neoadjuvant chemotherapy combined with cisplatin, etoposide, and bleomycin (PEB), vaginoscopic examination and laparoscopy revealed a uterine YST without metastasis. The patient was treated with laparoscopic hysterectomy and two cycles of PEB postoperatively. During the 18 months of follow-up, the patient remained disease-free.

SUMMARY AND CONCLUSION

Primary uterine YST is extremely rare and no treatment guidelines have been established to date. Surgery combined with PEB chemotherapy is considered effective for uterine YST.

Case report: Primary ovarian Burkitt's lymphoma: A puzzling scenario in pediatric population

Burkitt's lymphoma (BL) is defined as a highly invasive B-cell lymphoma, usually characterized by an excellent prognosis, more than 90% of children and adolescents being cured with highly dose-intensive multiagent chemotherapy. Primary ovarian localization without involvement of other organs is a rare manifestation of BL, especially in pediatric population. Symptoms at diagnosis are similar to other ovarian lesions and differential diagnosis may be challenging for clinicians. A 12-year-old girl was referred to our institution for abdominal pain and palpable mass observed by the pediatrician. Diagnostic work-up demonstrated a large mass arising from the right ovary, causing compression on abdominal aorta, inferior vena cava, ureters and bowel, with a second smaller lesion on the left ovary. At surgery, a 15 cm-large, ruptured mass arising from the right ovary was found, associated with a second lesion originating from the left ovary (8 cm) and multiple nodules of the greater omentum. Right salpingo-oophorectomy was performed, incisional biopsies were taken from the left ovary and omental nodules and peritoneal fluid samples were collected for cytology. Pathology revealed a Burkitt lymphoma and the patient underwent chemotherapy according to AIEOP LNH-97 Protocol, group R3 with Rituximab. Preoperative diagnosis of primary ovarian lymphoma is extremely difficult. Surgical exploration is often necessary in patients presenting with acute abdominal or pelvic pain; when the suspicion of primary ovarian lymphoma arises intraoperatively, every effort should be made to minimize invasive procedure in order to enhance post-operative recovery.

Outcome of Postchemotherapy Residual Disease in Extracranial Germ Cell Tumor in Children: Experience of a Tertiary Care Center

OBJECTIVES

The aim was to review outcome with residual disease at the end of first line chemotherapy in patients with extracranial germ cell tumor (GCT) in our resource limited setting.

METHODS

A retrospective analysis of 196 patients with GCT recruited at Shaukat Khanum Memorial Cancer Hospital (SKMCH) from January 2008 to December 2016. Data fields included site, histopathology, stage, risk groups, baseline alpha fetoprotein, beta human chorionic gonadotropin levels, residuum after primary treatment, completeness of surgical excision and outcomes. Data analysis involved quantitative analysis, mean and median calculations, event free survival (EFS) and overall survival (OS) calculations using Kaplan-Meier curves.

RESULTS

In 196 included patients, M:F ratio was 1. There were 81 (41.3%) adolescents. Alpha fetoprotein was >10,000 IU/L in 56 (28.6%) patients. Sixty-two (31.6%) patients had extragonadal disease. Most patients (n=137, 69.9%) presented with advanced stage (III/IV). Seventy-six patients had postchemotherapy residual disease (n=59 [78%] with partial response (PR) and 17 [22%] with no response [NR]). Five-year OS was 83% and EFS was 67%. Five-year EFS of patients with complete remission after primary chemotherapy was 85% versus 70% in patients with PR and 6% in those with NR (P=0.001). OS in patients with complete remission, PR and NR was 94%, 87%, and 46%, respectively. All patients with NR progressed or relapsed and 8/17 died. Four patients with normalized tumor marker response were found to have active tumor on resection of postchemotherapy residuum.

CONCLUSION

Patients with postchemotherapy residual disease in pediatric extracranial GCTs, fare better if their residuum is resected compared with those who do not undergo resection.

Treatment and Survival of Malignant Extracranial Germ Cell Tumours in the Paediatric Population: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis was performed to explore overall survival (OS) and event free survival (EFS) rates internationally over the past two decades and to define specific subgroups with inferior outcomes which may demand different treatment strategies.

METHODS

The search focused on malignant extracranial germ cell tumours (GCTs) in the paediatric population. The initial database search identified 12,556 articles; 32 articles were finally included in this review, comprising a total of 5095 patients.

RESULTS

The studies were heterogeneous, varying from single institution reports to large prospective trials. Older studies, describing eras where non-platinum-based chemotherapy regimens were used, showed clearly worse outcomes. Survival for stage I-II gonadal disease is excellent. On the other hand, patients with an initial alpha-fetoprotein (AFP) > 10,000 ng/mL or kU/L, age > 11 years and stage IV disease confer a survival disadvantage. For testicular disease in particular, lymphovascular invasion and certain histopathological subtypes, such as embryonal carcinoma (EC) and mixed malignant GCTs, survival is poorer. Survival data for sacrococcygeal and mediastinal GCTs show a heterogeneous distribution across studies in this review, independent of year of publication. Patients > 12 years presenting with a mediastinal GCT pose a subpopulation which fares worse than GCTs in other locations or age groups. This is independent of AFP levels, stage of disease or treatment protocol, and these patients may demand a different treatment strategy.

CONCLUSIONS

This review describes the heterogeneous nature of GCTs in different anatomical locations, impacting on stage at presentation, treatment modalities used and survival data. Despite this heterogeneity, in line with the current developmental biology-based classification system, subpopulations can be defined which have an inferior EFS and OS and where future research and more individualised treatment would help to improve survival.

Molecular Biology of Pediatric and Adult Male Germ Cell Tumors

Simple Summary

Although testicular germ cell tumors (TGCTs) are rare pediatric malignancies, they are the most common malignancies in young adult men. The similarities and differences between TGCTs in adults and children, taking into account the clinic presentation, biology, and molecular changes, are underexplored. In this paper, we aim to provide an overview of the molecular aspects of TGCTs, drawing a parallel between the findings in adult and pediatric groups.

Abstract

Cancer is a leading cause of death by disease in children and the second most prevalent of all causes in adults. Testicular germ cell tumors (TGCTs) make up 0.5% of pediatric malignancies, 14% of adolescent malignancies, and are the most common of malignancies in young adult men. Although the biology and clinical presentation of adult TGCTs share a significant overlap with those of the pediatric group, molecular evidence suggests that TGCTs in young children likely represent a distinct group compared to older adolescents and adults. The rarity of this cancer among pediatric ages is consistent with our current understanding, and few studies have analyzed and compared the molecular basis in childhood and adult cancers. Here, we review the major similarities and differences in cancer genetics, cytogenetics, epigenetics, and chemotherapy resistance between pediatric and adult TGCTs. Understanding the biological and molecular processes underlying TGCTs may help improve patient outcomes, and fuel further investigation and clinical research in childhood and adult TGCTs.

Testis-sparing surgery for testicular tumors in children: a 20 year single center experience and systematic review of the literature

PURPOSE

Although surgical therapy for testicular tumors (TT) is often radical orchidectomy, tumor resection with preservation of healthy testicular parenchyma has been proposed. This study herein reports a 20 year single center experience applying testicular sparing surgery (TSS) as a primary operative strategy in pediatric patients. A systematic literature review summarizes the utility and outcomes of TSS in appropriately selected patients.

METHODS

Pediatric patients with TT who underwent TSS between 1997 and 2018 were studied. TSS was indicated if patients presented evidence of adequately spared healthy testicular parenchyma on preoperative ultrasound and negative serum tumor markers. A systematic review of the literature was also performed.

RESULTS

12 cases met full inclusion criteria with 10 of 12 subjects in the prepubertal age group. Follow-up was 73 months (range 18-278 months). Only a single male patient (GSCCT) presented with early recurrence and orchidectomy was then performed. No cases of postoperative testicular atrophy were identified. Sexual maturation (Tanner stage) expected for age in each patient was documented. Review of the literature identified 34 published studies including 269 patients (94% prepubertal). Pathologic lesions here were mainly mature teratoma(s)-(62%) with a follow-up period of 4 years. Recurrent tumors were observed in only three patients (1.1%) notably two Leydig Cell Tumors and one Teratoma. Testicular atrophy reportedly occurred in only one single case (0.37%).

DISCUSSION

TSS is a feasible alternative to radical orchidectomy in pediatric male patients with localized TT and negative tumor markers. Long term follow-up is essential to monitor testicular growth, puberty with sexual development and psychological male health.

Immune Checkpoints in Pediatric Solid Tumors: Targetable Pathways for Advanced Therapeutic Purposes

The tumor microenvironment (TME) represents a complex network between tumor cells and a variety of components including immune, stromal and vascular endothelial cells as well as the extracellular matrix. A wide panel of signals and interactions here take place, resulting in a bi-directional modulation of cellular functions. Many stimuli, on one hand, induce tumor growth and the spread of metastatic cells and, on the other hand, contribute to the establishment of an immunosuppressive environment. The latter feature is achieved by soothing immune effector cells, mainly cytotoxic T lymphocytes and B and NK cells, and/or through expansion of regulatory cell populations, including regulatory T and B cells, tumor-associated macrophages and myeloid-derived suppressor cells. In this context, immune checkpoints (IC) are key players in the control of T cell activation and anti-cancer activities, leading to the inhibition of tumor cell lysis and of pro-inflammatory cytokine production. Thus, these pathways represent promising targets for the development of effective and innovative therapies both in adults and children. Here, we address the role of different cell populations homing the TME and of well-known and recently characterized IC in the context of pediatric solid tumors. We also discuss preclinical and clinical data available using IC inhibitors alone, in combination with each other or administered with standard therapies.

Primary intracranial pure endodermal sinus tumor: A retrospective series of 6 cases in a single center and a systematic review of overall survival

BACKGROUND

Primary intracranial pure endodermal sinus tumor (EST) is a rare malignant nongerminomatous germ cell tumor. There is still lack of knowledge about the treatment and prognosis.

METHODS

We studied 6 cases of primary intracranial pure EST patients in Beijing Tiantan Hospital from June 2009 to June 2015. A comprehensive literature search was performed on Pubmed's electronic database using the search terms "primary intracranial endodermal sinus tumor", "primary intracranial yolk sac tumor" and "malignant germ cell tumor". Survival rates based on age, gender, tumor location, treatment, resection degree and metastatis were collected and analyzed.

RESULTS

Total resection was achieved in three patients and subtotal resection was achieved in three patients. Blood AFP level continuously decreased after tumor removal. In our case series, the longest survival time was 99 months; this patient received surgery+adjuvant therapy. Fifty-two cases were eligible and met the inclusion criteria for the review analysis. The majority of the population were in the young child to adolescent age and there is a male predominance in this study. In the Kaplan-Meier survival analysis, age, gender, tumor location and metastasis did not affect patients' OS. Better OS was found in patients who had subtotal and gross total resection of the tumor. Patients who had surgery combined with adjuvant therapy showed better OS compared to those who just had surgery.

CONCLUSION

Total resection of the tumor is necessary and EST is sensitive to adjuvant therapy.

Management of Germ Cell Tumors in Pediatric Patients

Germ cell tumors arise from primordial germ cells. Most develop in the gonads or along midline structures of the body. Genetic aberrations leading to disruption in the molecular signaling responsible for primordial germ cell migration early in development may provide rationale for why germ cell tumors originate in extragonadal locations. Establishing best practices for treating pediatric germ cell tumors remains an area of active investigation. Recent advances focused on limiting toxicities of therapy, identifying new therapies for relapsed and refractory tumors, defining best practices for surgical staging and resection, and developing novel methods to monitor for disease relapse.

Management of Adrenal Tumors in Pediatric Patients

Pediatric adrenal tumors are uncommon entities that are frequently occult and identified incidentally or by recognizing symptoms related to hormone overproduction. They often have a genetic underpinning, arise from the medulla or cortex, can be malignant or benign, and require precise diagnostic algorithms. However, pseudotumors must also be a diagnostic consideration. Therapeutic interventions and plans are tumor dependent, but surgery is a cornerstone of treatment. Ongoing surveillance after treatment, regardless of malignant determination, is of utmost importance as well.

Malignant sacrococcygeal germ cell tumors in children in Taiwan: A retrospective single-center case series

Although the incidence of malignant sacrococcygeal germ cell tumors (MSGCTs) is high in the East Asian countries, information about MSGCTs from this region is limited. This report aimed to analyze the data of children with MSGCTs in a single medical center in Taiwan.Patients aged 18 years or younger with primary MSGCTs or malignant recurrence of a sacrococcygeal teratoma who underwent surgery during the neonatal period between January 1999 and December 2016 were identified from the Linkou Chang Gung Cancer Center registry. The clinical features, laboratory data, and treatment outcomes were reviewed.Fifteen children (1 man and 15 women) with MSGCTs were identified. Sacrococcygeal tumors were present at birth in 7 patients. All patients presented with a bulging mass at the buttock region and they had normal alpha-fetoprotein levels at the time of diagnosis. They underwent primary excision of the tumor. Immature teratoma was histologically diagnosed in 5 neonates, and mature teratoma in 2. Only 1 patient with grade 3 immature teratoma received adjuvant chemotherapy. Two patients with mature teratoma developed malignant recurrence 1.6 and 2.1 years later, respectively. Eight patients were diagnosed with MSGCTs after the neonatal period. The common presenting symptoms included buttock asymmetry (37.5%), abdominal distension (25%), and constipation (12.5%). Seven patients had elevated alpha-fetoprotein levels for their age. They were administered neoadjuvant chemotherapy followed by tumor excision if a residual tumor was present. The histology of the excised tumor included mature teratoma (66.7%) and necrosis (33.3%). One patient with a normal alpha-fetoprotein level underwent primary tumor excision followed by adjuvant chemotherapy. Grade 2 immature teratoma with embryonal carcinoma was diagnosed histologically. Among the 15 patients with MSGCTs, 3 had a recurrence (at age of 2.1, 0.5, and 2.4 years, respectively) and 1 died (at age of 6.1 years) of disease progression. The 5-year overall and event-free survival rates were 90% and 80%, respectively.Children with MSGCTs had good overall prognoses in this case series. For those with sacrococcygeal mature teratoma or low-grade immature teratoma in the neonatal period, we recommend close follow-up for at least 3 years after surgery to detect malignant recurrence.

Testicular tumors in children and adolescents: long-term endocrine and fertility issues

The treatment modalities for testicular tumors (surgery, chemotherapy, and radiotherapy), have different associated gonadotoxic risks and the overall survival for most pediatric patients with testicular tumors is very good. However, necessary treatments may lead to the development of lasting gonadal dysfunction and subsequent negative health and quality of life impact. Research with long-term follow-up for patients who have undergone surgery as the sole treatment modality for testicular tumors in childhood are lacking. It is currently unclear if surgery leads to long-term negative functional outcomes. Alkylating agents (e.g., cyclophosphamide) have long been known to increase risk of infertility; platinum-based therapies used frequently for patients with germ-cell tumors (GCTs) also seem to carry some risk of gonadotoxicity, although they have not been as well studied. Radiotherapy to the gonads is toxic and Leydig cells are particularly sensitive to high doses of radiation (>12 Gy). Long-term fertility and hormonal impact vary based on the patient’s age, as well as the type and intensity of the oncological treatment prescribed. Counselling regarding fertility risk and preservation options should ideally take place before initiating potentially gonadotoxic treatments. Hypogonadism in peri-pubertal boys can present as delayed onset or failure to progress through puberty. Sperm cryopreservation should be offered for post-pubertal boys who are able to provide a semen sample. For prepubertal boys or young males who cannot provide a semen sample, only experimental options are currently available. Much of the data reviewed here is extrapolated from research done on adult males whose reproductive and hormonal outcomes may not be comparable to younger patients who do not yet have fully developed reproductive systems. Currently, a lack of good quality evidence in this age range causes this restriction to be unavoidable. Patients and their families want to be informed of the risks and treatment options for preserving testicular function. As research continues in this field, it grows more important for urologists to be aware of the outcomes and options for their patients.

Etoposide and etoposide phosphate hypersensitivity in children: Incidence, risk factors, and prevention strategies

Introduction

Etoposide is critical in treating pediatric cancers, although hypersensitivity can be severe and treatment-limiting. Reported rates of hypersensitivity range from 2% to 51%. Hypersensitivity data for etoposide phosphate, a newer product, are lacking. The primary objective of this study was to assess etoposide and etoposide phosphate hypersensitivity incidence. Secondary objectives included evaluation of potential risk factors for hypersensitivity and strategies to prevent recurrence.

Methods

This retrospective cohort study evaluated pediatric patients who received initial etoposide phosphate or etoposide dose between August 2012 and July 2017. The primary outcome was documentation of hypersensitivity within four months of initial dose. Potential risk factors evaluated included age, allergies, dose, infusion rate, infusion concentration, and premedication.

Results

Of 246 patients, hypersensitivity reactions occurred in five of 54 patients (9.3%) who received etoposide phosphate and 52 of 192 patients (27.1%) who received etoposide ( p = 0.0061). For etoposide, the mean initial infusion rate was 64.6 ± 40.9 mg/m2/h for patients with hypersensitivity and 49.5 ± 33.4 mg/m2/h without hypersensitivity ( p = 0.0886). Etoposide phosphate rate was not associated with hypersensitivity. Recurrent hypersensitivity occurred in one of nine patients (11.1%) who received etoposide desensitization and one of 38 patients (2.6%) who changed formulation to etoposide phosphate.

Conclusions

Etoposide was associated with more hypersensitivity than etoposide phosphate in pediatric patients. Etoposide hypersensitivity was associated with higher infusion rates, but not etoposide phosphate. Differences in hypersensitivity incidence and infusion rate influence indicate a formulation-effect. Etoposide hypersensitivity recurrence may be prevented by changing to etoposide phosphate formulation. During etoposide phosphate shortages, etoposide desensitization may prevent recurrent hypersensitivity.

Results from the UK Children's Cancer and Leukaemia Group study of extracranial germ cell tumours in children and adolescents (GCIII)

BACKGROUND

For extracranial malignant germ cell tumours (MGCTs) in the UK, the GCII study used carboplatin-based chemotherapy (JEb) and demonstrated equivalent survival to cisplatin-containing protocols. GCIII, a single-arm observational study, used new risk stratification, replaced consolidation chemotherapy with a standard number of cycles and introduced surveillance for all stage I MGCTs. Pure teratomas were registered to understand their natural history.

METHODS

Patients with MGCTs were stratified to three risk groups - low risk (LR), intermediate risk (IR) and high risk (HR), using stage and prognostic factors. Patients with alpha fetoprotein (AFP) >10,000 kU/L, stage IV disease (except testis <5 years and all germinomas) or stage II-IV mediastinal tumour were classified HR. Stage I tumours (LR) received chemotherapy only if disease progressed. IR and HR patients received 4 and 6 JEB cycles, respectively. Carboplatin dose was calculated using glomerular filtration rate to give an area under the curve of 7.9 ml/m².min.

RESULTS

Eighty-six patients with MGCTs were enrolled from 2005 to 2009: 59% female, median age, 5.7 years. Twenty-five patients were LR, 21 IR and 38 HR. Seven LR patients had disease progression; all were successfully treated with chemotherapy. Overall survival (OS) for the whole group was 97%; 5-year event-free survival for JEb-treated patients was 92%, and OS, 95%. JEb was well tolerated with no observed significant hearing or renal side-effects. There was no discernible difference in carboplatin dose whether calculated by body surface area or creatinine clearance. Forty-seven patients with teratoma were managed with surgery and one had malignant transformation.

CONCLUSION

Carboplatin-based chemotherapy as part of a risk-stratified approach leads to excellent survival in paediatric MGCTs, minimising potential burden of long-term effects.

Clinicopathologic Features and Chromosome 12p Status of Pediatric Sacrococcygeal Teratomas: A Multi-institutional Analysis

Chromosome 12p gains are typically present in postpubertal male patients with testicular malignant germ cell tumors, including most teratomas, and absent in pure ovarian teratomas, both mature and immature. We sought to evaluate the clinicopathologic features and chromosome 12p status of pediatric patients with sacrococcygeal teratomas (SCTs) using the institutional databases of 2 tertiary medical centers. Seven mature teratomas (3 pure, 2 with yolk sac tumor, 1 with medulloepithelioma, and 1 with ependymoma) and 3 immature teratomas (2 pure: grade 2 and grade 3 and 1 mixed: grade 3 with yolk sac tumor) were identified. All patients underwent surgery and 2 received adjuvant chemotherapy. Fluorescence in situ hybridization analysis was performed to elucidate chromosome 12p gains, including isochromosome 12p. All 10 tumors analyzed lacked 12p gains regardless of the components. No patient had evidence of disease at their most recent interval follow-up (mean: 30, range: 7-91 months), irrespective of margin status or of receiving chemotherapy. Overall, our study suggests an absence of chromosome 12p abnormalities in clinically nonaggressive SCTs. Additional data are required to confirm these findings before definitive patient care recommendations can be made.

Pediatric mediastinal germ cell tumors

Mediastinal germ cell tumors (GCTs) are a rare and heterogeneous group of neoplasms. Although histologically resembling their gonadal counterparts, they differ considerably in their clinical characteristics, biological behavior and prognostic outcome. The rarity of mediastinal GCTs has hindered their meaningful analysis, with most studies and clinical trials including them along with other extragonadal GCTs, which has led to a lack of consensus on optimal treatment strategies, and a lull in improvement in patient outcomes. Diagnosis of mediastinal GCT requires a multipronged approach, and encompasses multidisciplinary treatment including chemotherapy followed by surgery, with or without radiotherapy. In view of sustained response rates to current management protocols, the focus needs to be shifted to identifying patients in whom treatment regimens can be downscaled with the aim of decreasing long term morbidity and improving quality of life in low risk patient groups, while improving survival rates in poor risk patient subsets. In this scenario, better understanding of the molecular pathogenesis of these tumors may lead to identification of novel biomarkers and therapeutic targets, as well as improved disease segmentation and risk stratification, thus helping to avoid the toxicity and morbidity associated with current one-fits-all treatment strategies. Multi-institutional collaborations across continents are necessary to generate meaningful data, and are the face of future developments in this arena.

Tumor-infiltrating T cells and PD-L1 expression in childhood malignant extracranial germ-cell tumors

Although pediatric malignant extracranial germ-cell tumors (meGCTs) are among the most chemosensitive solid tumors, a group of patients relapse and die of disease. To identify new markers predicting clinical outcome, we examined the prognostic relevance of tumor-infiltrating T lymphocytes (TILs) and the expression of PD-1 and PD-L1 in a cohort of pediatric meGCTs by in situ immunohistochemistry. MeGCTs were variously infiltrated by T cell-subtypes according to the tumor subtype, tumor location and age at diagnosis. We distinguished three different phenotypes: i) tumors not infiltrated by T cells (immature teratomas and half of the yolk sac tumors), ii) tumors highly infiltrated by CD8⁺ T cells expressing PD-1, which identifies activated tumor-reactive T cells (seminomas and dysgerminomas), iii) tumors highly infiltrated by CD8⁺ T cells within an immunosuppressive tumor microenvironment characterized by CD4⁺FOXP3⁺ Treg cells and PD-L1-expressing tumor cells (embryonal carcinomas, choriocarcinomas and the remaining yolk sac tumors). Tumor subtypes belonging mixed meGCTs were variously infiltrated, suggesting the coexistence of multiple immune microenvironments either facilitating or precluding the entry of T cells. These findings support the hypothesis that TILs influence the development of meGCTs and might be of clinical relevance to improve risk stratification and the treatment of pediatric patients.

Pediatric Germ Cell Tumors: A Developmental Perspective

Germ cell tumors (GCTs) arising in infants, children, and adolescents present a set of special challenges. GCTs make up about 3% of malignancies in children aged 0–18 and nearly 15% of cancers in adolescents. Epidemiologic and molecular evidence suggests that GCTs in young children likely represent a distinct biologic group as compared to GCTs of older adolescents and adults. Despite this difference, pediatric GCTs are typically treated with cisplatin-based multiagent regimens similar to those used in adults. There is evidence that children are particularly vulnerable to late effects of conventional therapy, including ototoxicity, pulmonary abnormalities, and secondary malignancies, motivating the search for molecular targets for novel therapies. Evidence is accumulating that the genes and mechanisms controlling normal germ cell development are particularly relevant to the understanding of germ cell tumorigenesis. Perturbations in the epigenetic program of germ cell differentiation, with resulting effects on the regulation of pluripotency, may contribute to the marked histologic variability of GCTs. Perturbations in the KIT receptor signaling pathway have been identified via next-generation sequencing studies and in genome-wide association studies of testicular cancer susceptibility. Here, we review these and other biological insights that may fuel further translational and clinical research in childhood GCTs.

The clinical impact of 18F-FDG PET/CT in extracranial pediatric germ cell tumors

BACKGROUND

Extracranial germ cell tumors are an uncommon pediatric malignancy with limited information on the clinical impact of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the literature.

OBJECTIVE

The purpose of this study was to evaluate and compare the clinical impact on management of ¹⁸F-FDG PET/CT with diagnostic computed tomography (CT) in pediatric extracranial germ cell tumor.

MATERIALS AND METHODS

The list of ¹⁸F-FDG PET/CT performed for extracranial germ cell tumor between May 2007 and November 2015 was obtained from the nuclear medicine database. ¹⁸F-FDG PET/CT and concurrent diagnostic CT were obtained and independently reviewed. Additionally, the patients' charts were reviewed for duration of follow-up and biopsy when available. The impact of ¹⁸F-FDG PET/CT compared with diagnostic CT on staging and patient management was demonstrated by chart review, imaging findings and follow-up studies.

RESULTS

During the study period, 9 children (5 males and 4 females; age range: 1.6-17 years, mode age: 14 years) had 11 ¹⁸F-FDG PET/CT studies for the evaluation of germ cell tumor. Diagnostic CTs were available for comparison in 8 patients (10 ¹⁸F-FDG PET/CT studies). The average interval between diagnostic CT and PET/CT was 7.2 days (range: 0-37 days). In total, five lesions concerning for active malignancy were identified on diagnostic CT while seven were identified on PET/CT. Overall, ¹⁸F-FDG PET/CT resulted in a change in management in 3 of the 9 patients (33%).

CONCLUSION

¹⁸F-FDG PET/CT had a significant impact on the management of pediatric germ cell tumors in this retrospective study. Continued multicenter studies are required secondary to the rarity of this tumor to demonstrate the benefit of ¹⁸F-FDG PET/CT in particular clinical scenarios.

Maternal Preeclampsia and Odds of Childhood Cancers in Offspring: A California Statewide Case-Control Study

BACKGROUND

Preeclampsia is a major cause of adverse effects on fetal health. We examined associations between fetal exposure to preeclampsia and subsequent odds of childhood cancers.

METHODS

We obtained childhood cancer cases (n = 13 669) diagnosed at 5 years old or younger between 1988 and 2012 from the California Cancer Registry and linked them to birth certificates. Controls (n = 271 383) were randomly selected from all California births and frequency matched to cases by birth year. We obtained data regarding preeclampsia during pregnancy, labour, and delivery from the medical worksheet of the electronic birth record. We used unconditional logistic regression models with stabilised inverse probability weights to estimate the effect of preeclampsia on each subtype of childhood cancer, taking into account potential confounding by pregnancy characteristics. Marginal structural models were fitted to assess the controlled direct effects of preeclampsia, independent of preterm delivery and NICU admission.

RESULTS

Although a null association was observed for all cancer subtypes combined (odds ratio (OR) 1.0, 95% confidence interval (CI) 0.9, 1.2), preeclampsia was found to be associated with increased odds of two histological subtypes of germ cell tumours: seminomas (OR 8.6, 95% CI 1.9, 38.4) and teratoma (OR 3.0, 95% CI 1.7, 5.4), but not yolk sac tumours in children. Odds remained elevated after adjusting for preterm delivery and NICU admission. Increases in odds were also observed for hepatoblastoma, however this association was attenuated in marginal structural models after accounting for NICU admission.

CONCLUSIONS

These findings suggest that maternal preeclampsia is associated with higher odds of some rare childhood cancers and may shed light on new aetiological factors for these cancers.