Report From the International Society of Urological Pathology (ISUP) Consultation Conference on Molecular Pathology of Urogenital Cancers: IV: Current and Future Utilization of Molecular-Genetic Tests for Testicular Germ Cell Tumors

The Status of Spermatogenesis in Germ Cell Tumor Bearing Testis and Its Association with Metastatic Disease

INTRODUCTION

We aimed to evaluate the status of spermatogenesis detected by histological examination of non-tumoral testicular tissues in tumor bearing testis and its association with advanced stage disease.

PATIENTS AND METHODS

We retrospectively reviewed patients with testicular germ cell tumors (TGCTs) that undergone radical orchiectomy. All non-tumoral areas of the orchiectomy specimens were examined for the status of spermatogenesis. Patients were divided into two groups as localized (stage I) and metastatic (stage II-III) disease and analyzed separately for seminomatous (SGCT) and nonseminomatous germ cell tumors (NSGCT).

RESULTS

Four hundred fifty-four patients were included in our final analysis. Of those, 195 patients had SGCT, and 259 patients had NSGCT. Three hundred and six patients had localized disease at the time of diagnosis. Median (Q1-Q3) age was 31 (26 - 38) years and 102 (22.5%) patients had normal spermatogenesis, 177 (39.0%) patients had hypospermatogenesis and 175 (38.5%) patients had no mature spermatozoa. On multivariate logistic regression analysis, embryonal carcinoma >50% (1.944, 95 %CI 1.054-3.585, P = .033) and spermatogenesis status (2.796 95% CI 1.251-6.250, P = .012 for hypospermatogenesis, and 3.907, 95% CI 1.692-9.021, P = .001 for absence of mature spermatozoa) were independently associated with metastatic NSGCT. However, there was not any variables significantly associated with metastatic SGCT on multivariate logistic regression analysis.

CONCLUSION

Our study demonstrated that only 22.5% of patients with TGCTs had normal spermatogenesis in tumor bearing testis. Impaired spermatogenesis (hypospermatogenesis or no mature spermatozoa) and predominant embryonal carcinoma are associated with advanced stage NSGCT.

Successful Multimodal Treatment of Intracranial Growing Teratoma Syndrome with Malignant Features

Molecular analysis of the growing teratoma syndrome has not been extensively studied. Here, we report a 14-year-old boy with a growing mass during treatment for a mixed germ cell tumor of the pineal region. Tumor markers were negative; thus, growing teratoma syndrome was suspected. A radical resection via the occipital transtentorial approach was performed, and histopathological examination revealed a teratoma with malignant features. Methylation classifier analysis confirmed the diagnosis of teratoma, and DMRT1 loss and 12p gain were identified by copy number variation analysis, potentially elucidating the cause of growth and malignant transformation of the teratoma. The patient remains in remission after intense chemoradiation treatment as a high-risk germ cell tumor.

Changes in adhesion molecules: β-catenin, E-cadherin and Galectin-3 in cells of testicular seminoma

Introduction

The most common testicular tumors are seminomas. They are characterized by rapid growth and a very high potential for metastasis to other organs. Mutual interactions of tumor cells play an important role in the invasiveness and metastatic capacity, in which complexes of adhesion proteins play a special role. There is a lack of studies on changes in these molecules and their behaviour in testicular cancer. The aim of the study was immunohistochemical identification and evalutaion of adhesive molecules β-catenin, E-cadherin, galectin-3 in testicular cancer - seminoma.

Methods

Tests were performed on sections of testicular cancer - seminoma in comparison with unchanged tissue samples as a control. Material was taken from 30 patients who underwent orchiectomy. Immunohistochemistry and PCR were used to identify β-catenin, E-cadherin and galectin-3 and gene expression.

Results

Immunoreactivity and expression of β-catenin and E-cadherin in seminomas were markedly decreased compared to non-cancerous testicular tissue. Galectin-3 immunoreactivity was found in both control and cancerous tissue, but in different location. In non-cancerous tissue, it was localized in the cytoplasm of the cells of the seminiferous tubules, in seminomas it was localized mainly in the endothelium. The expression of the Lgals3 gene encoding galectin-3 in seminomas was slightl higher in relation to the tissue unchanged by the carcinogenetic process.

Conclusions

The results of the study suggest a significant role of β-catenin, E-cadherin and galectin-3 in the carcinogenesis of seminomas and may indicate new aspects of the patomechanism of seminomas formation, and thus time lead to better understand the biology of these tumors.

Testicular cancer: new developments, molecular pathology, and current research keynote

Germ cell tumors (GCTs) are now considered a curable cancer, with a > 95% cure rate in all patients and about 90% cure rate in patients with metastatic disease. The success of physicians in curing the disease is underpinned by multidisciplinary advances. Of relevance in this regard are the nowadays-applied homogeneous terminology based on pathologically better characterized testicular neoplasms and the development of a widely used risk stratification model for metastatic disease introduced by the International Germ Cell Cancer Collaborative Group in 1997 and updated in 2021. Non-pulmonary visceral metastases, high levels of the serum tumor markers alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG), and primary mediastinal non-seminoma are currently identified as determinants of poor prognosis. In addition, the presence of distinct microRNA profiles between seminomas and non-seminoma GCTs has opened up important perspectives in terms of noninvasive biomarkers that can be used in diagnosis and treatment monitoring.

Molecular Biomarkers With Potential Clinical Application in Testicular Cancer

Testicular germ cell tumors (TGCTs) and sex cord-stromal tumors (SCSTs) are the most common testicular neoplasms. The morphologic spectrum of such tumors is wide, with several histologic subtypes within each group. Testicular tumors often represent a diagnostic challenge, requiring proper identification of their biologic potential for accurate risk stratification and selection of therapy. In the era of precision medicine, molecular biomarkers are increasingly assuming a critical role in the management of patients with cancer. Given the overall rarity of certain types of testicular neoplasms, progress in biomarker research has been relatively slow. However, in recent years, we have witnessed a multitude of important contributions, including both tissue-based and liquid biopsy biomarkers, stemming from important discoveries of tumor pathobiology, accurate histopathological analysis, multi-institutional studies, and genome-wide molecular analyses of specific tumor subtypes. In this review, we provide an overview of the progress in molecular biomarkers of TGCTs and SCSTs, focusing on those with greatest potential for clinical application. In TGCTs, developmental biology has been the key to understanding these tumors and identifying clinically useful biomarkers (from classical serum tumor markers to pluripotency factors and circulating microRNAs of the 371-373 cluster). For SCSTs, studies have focused on tissue biomarkers only, and genome-wide investigations have recently contributed to a better understanding of rare phenotypes and the aggressive biological behavior of some tumors within this nosologic category. Several new biomarkers are moving toward clinical implementation in this field. Therefore, the practicing pathologist should be aware of their strengths and limitations in order to utilize them properly and maximize their clinical benefits.

Isochromosome 12p Formation Regulates Vitamin D Metabolism in Testicular Cancer

Isochromosome 12p (iChr12p) is typical in almost all invasive testicular cancers. Increased copy number of genes on 12p is associated with the development of a clinically manifest tumor; however, the causative genes have not yet been identified. Chromosome 12 harbors many genes involved in Vitamin D metabolism. RNAseq analysis of Vitamin D receptor (VDR) genes from the TCGA cohort revealed that clustering of VDR expression signatures could differentiate between pure seminomas and non-seminomatous germ cell tumors (NSGCT). Using TCGA mRNA expression of anabolic (CYP2R1, CYP27A1 and CYP27B1) and catabolic (CYP24A1) Vitamin D enzymes, positive (PTHLH, IFNG, and TNF) and negative (FGF23) feedback regulators could also clearly distinguish between pure seminomas and NSGCT. We hypothesize that the regulation of Vitamin D metabolism might be disturbed through iChr12p formation, influencing testicular carcinogenesis via increased FGF23 and PTHLH expression. While FGF23 represses CYP27B1 and activates catabolism of active hormone, increased PTHLH secretion can lead to hypercalcemia via inactivation of VDR. In conclusion, testicular cancer is associated with extensive modifications in intratesticular Vitamin D homeostasis. Further research is needed to clarify whether Vitamin D deficiency causes the formation of iChr12p and whether Vitamin D deficiency via iChr12p genomic aberration is involved in testicular carcinogenesis.

An update on diagnostic tissue-based biomarkers in testicular tumors

Testicular cancer is rare overall but comprises the most common solid malignancy diagnosed in young men aged ∼20-40 years. Most testicular neoplasms generally fall into 2 broad categories: germ cell tumors (GCTs; ∼95%) and sex cord-stromal tumors (SCSTs ∼5%). Given the relative rarity of these tumors, diagnostic biomarkers are highly relevant for their diagnosis. Over the past several decades, diagnostic biomarkers have improved dramatically through targeted immunohistochemical and molecular characterization. Despite these recent advances, most markers are not perfectly sensitive or entirely specific. Therefore, they need to be used in combination and interpreted in context. In this review, we summarize tissue-based biomarkers relevant to the pathologist, with a focus on practical diagnostic issues that relate to testicular GCT and SCST.

12p gain is predominantly observed in non-germinomatous germ cell tumors and identifies an unfavorable subgroup of central nervous system germ cell tumors

BACKGROUND

Central nervous system (CNS) germ cell tumors (GCTs) are neoplasms predominantly arising in pediatric and young adult populations. While germinomas generally respond to chemotherapy and radiation, non-germinomatous GCTs (NGGCTs) require more intensive treatment. This study aimed to determine whether 12p gain could predict the prognosis of CNS GCTs.

METHODS

Eighty-two CNS GCTs were included in this study. The 12p gain was defined by an additional 12p in the background of potential polyploidy or polysomy. Cases were analyzed using an Illumina methylation 450K array for copy number investigations and validated by fluorescence in situ hybridization (FISH).

RESULTS

A 12p gain was found in 25-out-of-82 cases (30%) and was more frequent in NGGCTs (12% of germinoma cases and 50% of NGGCT cases), particularly in cases with malignant components, such as immature teratoma, yolk sac tumor, choriocarcinoma, and embryonal carcinoma. 12p gain and KIT mutation were mutually exclusive events. The presence of 12p gain correlated with shorter progression-free (PFS) and overall survival (OS) (10-year OS: 59% vs 94%, with and without 12p gain, respectively, P = 0.0002), even with histology and tumor markers incorporated in the multivariate analysis. Among NGGCTs, 12p gain still had prognostic significance for PFS and OS (10-year OS: 47% vs. 90%, respectively, P = 0.02). The 12p copy number status was shared among histological components in mixed GCTs.

CONCLUSIONS

12p gain may predict the presence of malignant components of NGGCTs, and poor prognosis of the patients. It may be associated with early tumorigenesis of CNS GCT.

Testicular Germ Cell Tumors: Classification, Pathologic Features, Imaging Findings, and Management

Testicular germ cell tumors (TGCTs) demonstrate a wide variety of histopathologic, genetic, pathogenetic, and immunocytochemical characteristics and various clinical-biologic profiles and prognoses. Most TGCTs arise from an intratubular precursor cell referred to as germ cell neoplasia in situ (GCNIS), which is an embryonic germ cell with the potential to differentiate into a plethora of embryonic and extraembryonic lineages. Advances in pathologic examination and genetics paved the way for the 2016 World Health Organization (WHO) classification system, which recognizes two pathogenetically distinct groups of TGCTs. Although postpubertal tumors originate from GCNIS, almost all prepubertal tumors belong to the non-GCNIS category. Molecular testing for chromosome 12p amplification helps to distinguish the two tumor categories. Imaging techniques such as US, CT, MRI, and fluorine 18 (¹⁸F)-fluorodeoxyglucose PET/CT are pivotal to the diagnosis and staging, evaluation of complications and treatment response, and long-term surveillance of TGCTs. In addition, select MRI findings may help to differentiate a seminoma from a nonseminomatous mixed TGCT. Accurate diagnosis of TGCTs has therapeutic and prognostic implications. Although seminomas show exquisite response to chemotherapy and radiation therapy, postpubertal teratomas are highly resistant to both. The 2016 WHO classification system introduced changes in the diagnosis and management of TGCTs, including the development of new treatment and follow-up guidelines. Radiologists play an essential role in the optimal treatment of patients with TGCTs. Online supplemental material is available for this article. ©RSNA, 2021.

Recurrence of a Mediastinal Germ-Cell Tumor as a Somatic-Type Malignancy: A Complex Case Report

Background and case: An adolescent male presented with a second mediastinal tumor 1.5 years after treatment of a proven malignant germ-cell tumor in that location. The differential diagnosis included a recurrent germ-cell tumor or a non-germ cell malignancy. Serum tumor markers alpha-fetoprotein (AFP) and human chorionic gonadotrophin (HCG) were negative. The first biopsy was not informative, and the second biopsy gave a broad differential diagnosis including secondary non-germ cell malignancy using histology and immunohistochemistry. DNA methylation profiling, RNA sequencing, and targeted microRNA371a-3p profiling was subsequently performed, without a supportive result. After resection of the tumor the definitive diagnosis yielded two secondary non-germ cell malignancies in the form of a leiomyosarcoma and a solitary neuro endocrine carcinoma (NEC). In spite of the differences between the molecular profiles of the initial germ-cell tumor, the leiomyosarcoma and large-cell NEC are clonally related, as determined by the presence of identical chromosomal breakpoints. The copy number profiles suggest an initial polyploidization step, followed by various independent chromosomal gains and losses. This case demonstrates that germ-cell tumors must be evaluated carefully, including molecularly, in which the non-germ cell malignancy is negative for miR-371a-3p, both in tissue as well as in serum, in contrast to the primary tumor. We conclude that the patient presented with a primary type II mediastinal GCT and, a year and a half later, followed by a leiomyosarcoma and a large-cell NEC presenting as two secondary somatic-type malignancies clonally related to the original GCT. Conclusions: Malignant germ-cell tumors are known to recur as a somatic-type malignancy in very rare cases. This case report illustrates the challenges faced in defining the nature and clonality of the secondary somatic-type malignancies.

A 25 year perspective on advances in the pathologic assessment and diagnosis of urologic cancers

Over the past 25 years, diagnostic categories in genitourinary pathology have changed dramatically. Prostate cancer reporting incorporated numerous new variant categories, recognized the importance of intraductal carcinoma, and introduced the concept of Grade Groups. Pathologic diagnosis of bladder cancer not only added new variant categories, but also modified the grading of non-invasive urothelial neoplasms and refined staging definitions. Kidney cancer classification expanded from a handful of diagnostic categories to a broad array of additional cancer types defined by unique immunohistochemical and molecular findings. Segregation of penile carcinoma by human papillomavirus status more accurately reflected pathogenesis and helped improve prediction of cancer behavior. Testicular pathology research advanced understanding of germ cell tumor subtypes and their impact on patient outcomes. Finally, adrenal gland pathology has evolved to incorporate a broader recognition of morphological variation and risk factors associated with tumor progression. Taken together, changes in pathology over the past quarter century have revolutionized our approach to genitourinary cancers. This review seeks to highlight some of the many significant changes in genitourinary pathology that have occurred during the past 25 years and emphasize impacts on clinical outcomes or therapy, as relevant.

Metastatic Seminoma with Positive Staining of Cytokeratin and MOC31: A Diagnostic Pitfall

Retroperitoneal metastasis of seminoma often occurs in the higher stage through lymph nodes. Generally, seminoma expresses specific germ cell markers while being negative for carcinoma markers. We present a unique case of cytokeratin positive seminoma initially presented as retroperitoneal metastasis. The diagnosis was made based on the histological features and immunohistochemical stains. Testicular ultrasound confirmed the primary tumor in the patient's left testicle. Pathologists should always be aware of germ cell tumors when encountering a metastasis of an unknown primary.

Circulating MicroRNAs, the Next-Generation Serum Biomarkers in Testicular Germ Cell Tumours: A Systematic Review

CONTEXT

Clinical management of testicular germ cell tumours (GCTs) is hampered by low sensitivity and specificity of the biomarkers currently in use. Circulating microRNAs (miRs) might offer the potential to address areas of unmet clinical need.

OBJECTIVE

To systematically evaluate the evidence for clinical applications of serum levels of miR302/367 and miR371-3 in adult testicular GCTs in terms of primary diagnosis, various clinical scenarios, and the costs of clinical implementation.

EVIDENCE ACQUISITION

We performed a critical review of PubMed/Medline, Embase and the Cochrane Library in January 2021 in accordance with Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement.

EVIDENCE SYNTHESIS

Thirty-one manuscripts addressed miR performance and potential clinical use in testicular GCT. Of these, 23 evaluated the utility in primary diagnosis, seven in early-stage disease, and 13 in metastatic disease, and two addressed the costs of clinical implementation. Of the various miRs studied, miR-371a-3p appears the most useful and potentially the only one that needs to be assayed, with an area under the receiver operating characteristic curve >0.90, sensitivity of 89-96%, and specificity of >90% for both seminoma and nonseminoma, surpassing the classic serum tumour markers. The miRs studied to date are not elevated in cases with teratoma only. Levels of miR-371a-3p correlate with primary tumour mass, clinical stage, and International Germ Cell Cancer Collaborative Group risk groups. Serial measurements mirror treatment efficacy in all clinical stages.

CONCLUSIONS

Circulating miRNA levels, particularly of miR-371a-3p, have potential for incorporation in clinical practice and may aid in clinical decision-making in various clinical scenarios in GCT.

PATIENT SUMMARY

We analysed the current evidence on the usefulness of blood levels of molecules called microRNAs in the management of testicular tumours. The microRNA-371a-3p molecule has better sensitivity and specificity than the markers currently being measured. This new biomarker may soon have a place in clinical practice.

Primary Testicular Neuroendocrine Tumor Coexisting With Seminoma Sharing Germ Cell Origin

A 40-year-old, male, Japanese patient presented with the complaint of painless, right testicular swelling. Tumor markers for testicular cancer were normal. He underwent radical orchiectomy with the clinical diagnosis of stage I seminoma. Pathological examination revealed seminoma and coexisting neuroendocrine tumor (NET). Germ cell neoplasia in situ (GCNIS) was present in the vicinity of seminoma, but there was no continuity between NET and seminoma. Tumor cells of both lesions displayed amplification of 12p and isochromosome 12p on fluorescence in situ hybridization, suggesting that both tumors originated from GCNIS. The present report is the first to describe a case of primary testicular NET coexisting with seminoma in an ipsilateral testis.

Terminal Deoxynucleotidyl Transferase Commonly Expresses in Germ Cell Tumors: Evaluation on a Large Series from Multiple Centers

Aim

The concrete features of expression of terminal deoxynucleotidyl transferase (TdT) are needed to be revealed in male and female germ cell tumors (GCTs).

Methods

TdT immunostaining was performed in 195 GCTs, and the tumor and/or tumorous components included seminomas, germ cell neoplasias in situ (GCNISs), dysgerminomas, embryonal carcinomas (ECs), extragonadal germinomas, yolk sac tumors (YSTs), teratomas, and spermatocytic tumors. Twenty-one sex cord-stromal tumors were also added. Expression of the classical germ cell tumor markers (PLAP, OCT4, SALL4, CD117, and D2-40) was compared to that of TDT.

Results

Nearly all (tumors or tumorous components) seminomas (99%, 107/108), GCNISs (98%, 51/52), dysgerminomas (94%, 17/18), ECs (100%, 15/15), and extragonadal germinomas (100%, 11/11) were positive for TdT. None of the cells in YSTs (0/38), teratomas (0/19), spermatocytic tumors (0/1), or sex cord-stromal tumors (0/21) were immunoreactive for TdT staining. The normal testicular and ovarian gonadal tissues were also negative for TdT. However, TdT presented with significant loss of antigen immunoreactivity in the paraffin-embedded tissues older than 3 years, giving rise to weak or moderate staining in a subset of cases. The expressions of TdT showed no significances with PLAP, OCT4, SALL4, CD117, and D2-40 during the diagnosis of the most GCTs (P>0.05), except for with PLAP, SALL4, or CD117 in YST (P=0.000 each), and D117 (P=0.000) or D2-40 (P=0.006) in ECs.

Conclusion

Our findings further verify that TdT can serve as a new GCT marker for seminomas, GCNISs, dysgerminomas, ECs, and extragonadal germinomas, with a highly positive rate. Awareness of TdT positivity in GCTs contributes to the prevention of erroneous diagnoses, particularly in the setting of core needle biopsies. To determine the properties where TdT staining may not be apparent in some old archived paraffin-embedded tissues, one could circumvent the potential misinterpretations of false-negative immunohistochemistry results.

Evaluation of an Algorithm for Testis-Sparing Surgery in Boys with Testicular Tumors: A Retrospective Cohort Study

Aim: This study reports surgical treatment and its outcome for boys with a testicular tumor, in order to analyze the considerations of testis-sparing surgery (TSS) and investigate whether, in retrospect, treatment was according to a recently developed algorithm. Methods: We retrospectively reviewed boys with testicular tumors who underwent surgical treatment between January 2000 and June 2020 at the Wilhelmina’s Children’s Hospital and the Princess Máxima Center for Pediatric Oncology, The Netherlands. Medical records were searched for clinical characteristics and outcome. Results: We identified 31 boys (median age = 5.5 years) with a testicular tumor, 26 germ cell tumors (GCTs), four sex cord-stromal tumors, and one gonadoblastoma. Seventeen boys (median age = 1.5 years) had malignant and 14 (median age = 3.6 years) had benign tumors. Four boys with benign GCTs were treated with TSS, 25 with radical inguinal orchiectomy (RIO), and 2 with scrotal orchiectomy. No recurrence or testicular atrophy was reported. All boys with benign testicular tumors were treated as suggested by the algorithm, except for one boy treated with RIO. Conclusion: Retrospective analysis of surgical treatment of prepubertal boys with benign testicular tumors showed that TSS appears to be safe, and should be considered based on clinicoradiological data, in line with our algorithm.

[Molecular pathology of urogenital tumors : Recommendations from the 2019 International Society of Urological Pathology (ISUP) Consensus Conference]

Das zunehmende Verständnis molekularer Grundlagen von Tumoren sowie der Fortschritt in der Diversifizierung der onkologischen Therapien versprechen individualisierte Therapieoptionen, welche bislang jedoch nur ansatzweise in die Therapieplanung von urologischen Tumoren eingegangen sind. Daher hat die Internationale Gesellschaft für Urologische Pathologie (ISUP) im März 2019 eine Konsenskonferenz zur Erarbeitung evidenzbasierter Handlungsempfehlungen zur molekularpathologischen Diagnostik beim Urothelkarzinom, Nierenzellkarzinom, Prostatakarzinom, Peniskarzinom und testikulären Keimzelltumoren durchgeführt. Die auf dieser Konsenskonferenz erarbeiteten Empfehlungen sind kürzlich in 5 separaten Manuskripten veröffentlich worden und werden in der vorliegenden Arbeit zusammengefasst.

Im Rahmen der Konferenzvorbereitung wurde eine umfassende Umfrage zur derzeitigen Praxis molekularer Testungen bei urogenitalen Tumoren unter den Mitgliedern der ISUP durchgeführt. Auf der Konferenz wurden die Ergebnisse und die entsprechenden Hintergrundinformationen durch 5 Arbeitsgruppen präsentiert und Handlungsempfehlungen für die Diagnostik erarbeitet. Eine Übereinstimmung von 66 % der Konferenzteilnehmer wurde als Konsens definiert.

The detection of isochromosome i(12p) in malignant germ cell tumours and tumours with somatic malignant transformation by the use of quantitative real-time polymerase chain reaction

AIMS

Malignant germ cell tumours (GCTs) of the testis are rare neoplasms, but the most common solid malignancies in young men. World Health Organization guidelines divide GCTs into five types, for which numerous immunohistochemical markers allow exact histological subtyping in the majority of cases. In contrast, a germ cell origin is often hard to prove in metastatic GCTs that have developed so-called somatic malignant transformation. A high percentage, up to 89%, of GCTs are characterised by the appearance of isochromosome 12p [i(12p)]. Fluorescence in-situ hybridisation has been the most common diagnostic method for the detection of i(12p) so far, but has the disadvantages of being time-consuming, demanding, and not being a stand-alone method. The aim of the present study was to establish a quantitative real-time polymerase chain reaction assay as an independent method for detecting i(12p) and regional amplifications of the short arm of chromosome 12 by using DNA extracted from formalin-fixed paraffin-embedded tissue.

METHODS AND RESULTS

A cut-off value to distinguish between the presence and absence of i(12p) was established in a control set consisting of 36 tumour-free samples. In a training set of 149 GCT samples, i(12p) was detectable in 133 tumours (89%), but not in 16 tumours (11%). In a test set containing 27 primary and metastatic GCTs, all 16 tumours with metastatic spread and/or somatic malignant transformation were successfully identified by the detection of i(12p).

CONCLUSION

In summary, the qPCR assay presented here can help to identify, further characterise and assign a large proportion of histologically inconclusive malignancies to a GCT origin.

The International Society of Urological Pathology Consultation on Molecular Pathology of Urogenital Cancer

The 2019 Consultation Conference on the molecular pathology of urogenital cancers was organized by the International Society of Urological Pathology (ISUP) to have an understanding of the current use of molecular-genetic markers and to make recommendations on their application in prostate, bladder, renal, testicular, and penile cancer. This brief introductory article describes the organization of this conference and provides its rationale and main findings.

Testis Sparing Surgery in Pediatric Testicular Tumors

Simple Summary

Testis sparing surgery (TSS) is a safe treatment option in selected cases of testicular tumors in adults, focusing on technical feasibility, oncologic safety, preserving of testicular function, and long-term outcome. This surgical technique is also increasingly being considered in children, as benign tumors are more common in this population. With this systematic review, we aim to evaluate outcome of TSS and to investigate under which circumstances TSS can be considered safe in boys with testicular tumors. Based on the current practice described in this systematic review, combined with the outcome of TSS, we would like to suggest an algorithm to guide clinicians in determining the appropriate surgical treatment in prepubertal patients less than 12 years of age with a testicular tumor. TSS may lead to improved testicular function and quality of life in boys with testicular tumors.

Abstract

Objective: The purpose of this review is to evaluate the outcomes of testis sparing surgery (TSS) and to investigate under which circumstances TSS can be considered a safe treatment option in pediatric patients with testicular tumors. Methods: A database search was performed in Cochrane, Pubmed, and Embase for studies that focused on TSS as treatment for testicular tumors in the pediatric population, excluding reviews and single case reports. Results: Twenty studies, describing the surgical treatment of 777 patients with testicular tumors, were included in the analysis. The majority of pediatric patients with benign germ cell tumors (GCTs) (mean age: 3.7 years) and sex cord-stromal tumors (SCSTs) (mean age: 6.6 years) were treated with TSS, 61.9% and 61.2%, respectively. No cases of testicular atrophy occurred. Four of the benign GCTs, i.e., three teratomas and one epidermoid cyst, recurred. No cases of recurrence were reported in patients with SCSTs. Of the 243 malignant GCTs (mean age: 4.2 years), only one patient had TSS (0.4%). Conclusion: TSS is a safe treatment option for prepubertal patients less than 12 years of age with benign GCTs and low grade SCSTs.

The decisive role of molecular pathology in presumed somatic metastases of type II testicular germ cell tumors: report of 2 cases

Background

Molecular diagnostics can be decisive in the differential diagnosis between a somatic metastasis of type II testicular germ cell tumor (TGCT) or a second primary carcinoma. This is in line with recent recommendations from the International Society of Urological Pathology, based on an international survey which showed that molecular testing is currently only performed by a minority of urological pathologists.

Case presentations

This case report illustrates the necessity of molecular testing in two patients with a history of type II TGCT and a metastatic (retro) peritoneal carcinoma years later. The genetic hallmark of type II TGCT, chromosome 12p gain, was studied by fluorescence in situ hybridization and whole genome methylation profiling in case 1, and by single nucleotide polymorphism (SNP)-array in case 2. Next generation sequencing (NGS) was used to further explore clonality between the primary TGCT and peritoneal metastasis in case 2. In case 1, chromosome 12p gain was found in the primary type II TGCT and in the acinar cell carcinoma of the metastatic malignancy. In case 2, SNP array showed 12p gain in the epithelial component of the primary teratomatous TGCT but not in the peritoneal adenocarcinoma. Furthermore, NGS showed no mutations in the primary teratomatous TGCT but a KRAS and GNAS mutation in the peritoneal adenocarcinoma, suggestive of an appendicular origin.

Conclusions

Without the molecular data, both cases would have been regarded as a metastatic TGCT with development of somatic-type malignancy, which appeared a wrong diagnosis for case 2. These cases demonstrate the importance of molecular methods as an adjunct in today’s pathology practice.