Klinefelter syndrome and mediastinal germ cell tumors

Mediastinal Tumor in a Boy With GnRH-Independent Precocious Puberty and Fluctuating β-HCG Levels

Gonadotropin-releasing hormone (GnRH(-independent premature puberty in boys, characterized by elevated β-human chorionic gonadotropin (β-hCG) levels, can indicate a secreting germ cell tumor (GCT). These tumors are rare but more common in individuals with Klinefelter syndrome (KS). We present a case of a 7.3-year-old boy with precocious puberty. Physical examination revealed bilateral testicular volumes of 8 to 10 mL and Tanner stage 3 secondary sexual characteristics (genitalia G3, pubic hair P3). His skeletal age was 12 years. Biochemical tests showed suppressed gonadotropin levels, elevated testosterone, and increased β-hCG of 86.6 mIU/mL (86.6 IU/L, reference range: <5 mIU/mL, <5 IU/L). Imaging, including magnetic resonance imaging (MRI), chest x-ray, whole-body computed tomography (CT), and testicular ultrasound, were interpreted as normal except for a small pineal cyst. Karyotype testing confirmed KS. Over 10 months, β-hCG levels fluctuated between 1 to 105 mIU/mL (1-105 IU/L). When β-hCG was 3.6 mIU/mL (3.6 IU/L), a fluorodeoxyglucose positron emission tomography-CT (FDG PET-CT) scan revealed a mediastinal tumor. The tumor was surgically removed and identified as a mature teratoma. This case underscores the importance of karyotype testing and repeated imaging in boys with premature puberty and elevated β-hCG levels, even if β-hCG levels decrease spontaneously and remain low.

Sperm extraction in nonmosaic Klinefelter syndrome patients: A case series and literature review of sperm extraction in Klinefelter syndrome patients

Objectives

Klinefelter syndrome (KF) is a group of chromosomal disorders with at least one extra X chromosome in male individuals that leads to infertility and diminished hair growth in affected males. In this study, we present a case series of 16 nonmosaic KF and an extensive literature review.

Patients and Methods

This is a retrospective study including 16 nonmosaic Klinefelter Syndrome patients that underwent micro-testicular sperm extraction (m-TESE) at our center between January 2016 and December 2022. Frequencies and percentages were used to present categorical variables, whereas continuous variables were presented as the median and interquartile range (IQR). The sperm retrieval rate (SRR) was assessed using a one-sample proportions test with continuity correction. Fisher's exact test was to assess the differences between patients with negative and positive retrieval in terms of the categorical variables. A Wilcoxon rank-sum test was applied to explore the between-group differences in the numerical variables. A literature search was performed for additional publications of discussing m-TESE among KF patients.

Results

The median (IQR) age of patients was 40.0 years (34.5-47.0). All of the patients had nonobstructive azoospermia, and the majority of them (93.8%) had primary infertility. The most common histopathological findings were atrophic tubules (57.1%), followed by Sertoli cell-only (28.6%). Sperm retrieval was positive for two patients with a rate of 12.5% (95% confidence interval 2.2 to 39.6). Patients with positive sperm retrieval were significantly younger than their peers with negative retrieval (median = 28.0, IQR = 27.5 to 28.5 vs. median = 41.5, IQR = 35.8 to 47.0, P = 0.031). The successful conception rate was 100% (n = 2) using intracytoplasmic sperm injection with a birth rate of 100% (n = 2).

Conclusion

Our observed SRR among nonmosaic KF patients was marginally lower than the reported literature. Younger-age patients were significantly more likely to benefit from the procedure.

Oncological diseases in Klinefelter Syndrome: an overview

Epidemiological studies have highlighted a higher incidence of morbidity and mortality among individuals with Klinefelter's Syndrome (KS), however, the relative impact of oncological diseases on KS subjects is still uncertain. While some malignancies (e.g., hematological and lung cancers) may show an increased prevalence in the KS population, only a few rare tumors (i.e., extragonadal germ cell tumors [GCTs] and male breast cancer [MBC]) seem to follow this trend. Additionally, hormonal and genetic determinants may be involved in the pathogenesis of neoplasia in KS, even if subjects affected by this syndrome generally show lower incidence of prostate cancer along with lower disease-specific mortality despite testosterone replacement therapy (TRT). This review deals with the pathophysiological and clinical aspects of neoplastic diseases occurring in KS.

Large mediastinal/thoracic benign teratoma presenting with haemoptysis: Report of a case and review of the literature

The mediastinal teratomas can grow to a large size before becoming symptomatic. The symptoms are usually due to the compression of adjacent structures. A computed tomographic scan of the chest is the investigation of choice for making a provisional diagnosis and planning for further management. Removal of large mediastinal/thoracic teratoma can be associated with various intraoperative and postoperative complications, which can be life-threatening sometimes. We operated on a patient with a large mediastinal mass extending into the right thoracic cavity up to the costo-phrenic angle. The postoperative period was eventful and required judicious intensive care. The patient eventually recovered with conservative treatment. A literature search was done on PubMed using the keywords benign mediastinal teratoma. Case series/original articles published in the last two decades, that is, after the year 2000, were evaluated. As per the review of the literature, the prevalence of benign mediastinal teratoma may be higher in eastern countries. Thoracoscopic surgery is the preferred modality except for cases with adhesions or infiltration into surrounding structures.

Treatment of congenital adrenal hyperplasia and Klinefelter Syndrome with central precocious puberty: a case report

The simultaneous occurrence of Klinefelter syndrome (KS) and congenital adrenal hyperplasia (CAH) is extremely rare, as the former causes androgen deficiency, while the latter results in androgen excess. In addition, central precocious puberty (CPP) will occur, which is caused by the activation of the hypothalamic-pituitary-gonadal (HPG) axis by androgens. We present the 7th reported case of simultaneous KS and CAH in a boy with CPP due to protopathy of CAH. He presented with increased gonadotropin and excessive androgen levels, and was diagnosed with KS due to his unexpected karyotype analysis results. This is the first reported case of an association between KS and CAH to undergo gonadotropin-releasing hormone analog (GnRHa) and recombinant human growth hormone (rhGH) therapy to increase his predicted final height. His predicted adult height was approximately 160 cm by estimation using the bone age as well as current height, which is much taller than the estimated height before treatment. Although KS may cause hypogonadism, the patient should be administered GnRHa and rhGH therapy if simultaneous CAH, CPP, and KS are present to increase the patient's predicted final height. Excessive androgen levels may mask the symptoms of KS-related hypogonadism during childhood; however, the patient should be made aware of the possibility of hypogonadism developing in the future.

Mediastinal mixed germ cell tumor: A case report and literature review

Mixed germ cell tumor (MGCT) mainly occurs in young women’s ovaries and men’s testicles and rarely occurs outside the gonad. Fewer than 10 cases of mediastinal MGCT are available in PubMed, Embase, and other databases in English, while mediastinal MGCT with three pathological components, such as yolk sac tumor, immature teratoma, and embryonal carcinoma, has not been reported previously. A 12-year-old male sought medical attention for chest discomfort and underwent a computed tomography (CT) scan. A large soft tissue mass occupying most of the left thoracic cavity and mediastinum was detected. A CT-guided biopsy was performed, and an MGCT was diagnosed with pathological components, including yolk sac tumor, immature teratoma, and a small amount of embryonal carcinoma. Due to the large size of the tumor, the patient was treated with an EP regimen (etoposide + cisplatin) and paclitaxel + ifosfamide + cisplatin interstitial chemotherapy. The patient was followed up for 6 months and was alive with the disease. To the best of our knowledge, this is the 10th patient with MGCT in the mediastinum. The incidence of mediastinal MGCT is low, but it should still be considered one of the differential diagnoses of isolated pleural fibroma and neurogenic tumors.

How Successful Is Surgical Sperm Retrieval in Klinefelter Syndrome?

Klinefelter Syndrome (KS) is characterized by the presence of an extra X chromosome. It was first diagnosed in 1942 in a group of azoospermic men. KS is the most common chromosomal abnormality encountered in infertile men and accounts for more than 10% of the causes of azoospermia. Men who are azoospermic may still father children via testicular sperm extraction followed by intracytoplasmic sperm injection (ICSI). This review article summarizes the success rates of the available techniques for surgical sperm retrieval (SSR) in KS including conventional testicular sperm extraction (cTESE) and micro testicular sperm extraction (mTESE), as well as the risks of these procedures for future fertility. The evidence indicates that the SSR rate is as successful in non-mosaic men with KS as those with normal karyotypes, with retrieval rates of up to 55% reported. The influence of different factors that affect the chances of a successful outcome are discussed. In particular, the impact of aneuploidy rate, physical characteristics, co-morbidities, reproductive endocrine balance and the use of different hormone management therapies are highlighted. Evidence is presented to suggest that the single most significant determinant for successful SSR is the age of the patient. The success of SSR is also influenced by surgical technique and operative time, as well as the skills of the surgeon and embryology team. Rescue mTESE may be used successfully following failed TESE in KS patients in combination with hormone stimulation.

Bilateral Testicular Epidermoid Cysts in a Man with Klinefelter Syndrome: A Case Report

Klinefelter syndrome is a rare chromosomal disorder with at least one extra X chromosome in males resulting in male hypogonadism, androgen deficiency and impaired spermatogenesis. It is associated with an increased risk of certain malignancies; including leukemia, breast cancer, non-Hodgkin's lymphoma and mediastinal germ cell tumors, however, testicular tumors are rare in men with Klinefelter syndrome. Testicular epidermoid cysts are rare benign tumors affecting the testes. We report a case of bilateral testicular epidermoid cysts in a 30-year-old man known to have Klinefelter syndrome. He had an incidental finding of bilateral hard irregular-surfaced testes during routine assessment for testosterone replacement therapy. Biochemical investigation confirmed primary hypogonadism and ultrasound imaging demonstrated bilateral solid testicular masses with no blood flow seen within the lesions. The patient went on to have a right-sided radical orchiectomy with left-side sparing. The histology revealed features in keeping with that of a testicular epidermoid cyst with no evidence of malignancy. The patient was commenced on testosterone replacement therapy. This case emphasizes the importance of routine physical examination of the male external and internal genitalia when considering testosterone replacement therapy.

SDHx and Non-Chromaffin Tumors: A Mediastinal Germ Cell Tumor Occurring in a Young Man with Germline SDHB Mutation

Background: Mutations in genes encoding one of the subunits of succinate dehydrogenase (SDH) are involved in pheochromocytoma (PHEO) and paraganglioma (PGL) development. Over the last few years, such mutations have also been associated with non-chromaffin tumors. However, immunohistochemistry (IHC) on the tumor tissue and a study on the loss of heterozygosity (LOH) aimed at demonstrating the pathogenic role of SDHx genes have only been employed in a few cases. Case report: We describe the case of a 19-year-old Caucasian man with a germline SDHB mutation, who presented with acne vulgaris resistant to medical treatment. His follow-up for chromaffin tumors was negative, while hormonal tests revealed suppressed gonadotropins with testosterone in the upper range of normality and elevated β-human chorionic gonadotropin (β-hCG). At the whole-body enhanced CT scan, a mediastinal lesion suggestive of a germ cell tumor (GCT) was detected. ¹⁸FDG-PET (fluorodeoxyglucose-positron emission tomography) imaging showed low glucose metabolism at the mediastinal site. Surgical removal of the mass was uneventful. Pathology confirmed the diagnosis of GCT consisting of cystic teratoma (95%) and seminoma (5%). IHC for SDHB showed normal protein expression, and genetic analysis of the tumor tissue revealed the absence of SDHB LOH. Normalization of the hormonal tests and acne attenuation were achieved after surgery. Conclusion: We report an incidental association of a germinal SDHB mutation and mediastinal GCT in a young Caucasian man. Our paper highlights the importance of IHC and genetic analysis in confirming the etiologic role of SDHx genes in nonchromaffin tumors, thus excluding incidental associations.

Klinefelter syndrome and germ cell tumors: review of the literature

Objective

The most common presentation of Klinefelter syndrome (KS) is infertility and features of hypogonadism. Currently no consensus exists on the risk of malignancy in this syndrome. Several case reports show an incidence of extragonadal germ cells tumors (eGCT) of 1.5 per 1000 KS patients (OR 50 against healthy population). Malignant germ cell tumors are rare in children. They account for 3% of all children cancers. Young patients with a germ cell tumor are not routinely tested for Klinefelter syndrome. This can therefore result in underdiagnosing. Literature data suggest a correlation between eGCT and KS. To the best of our knowledge there is no precise description of the primary locations of germ cell tumors in KS patients. The purpose of this study is to evaluate age groups and primary locations of extragonadal germ cell tumors in Klinefelter patients. With this data we investigate whether it is necessary to perform a cytogenetic analysis for KS in every eGCT patient.

Study design

This study is based on case report publications in PubMed/Medline published until march 2020 that described "Klinefelter Syndrome (MeSH) AND/OR extragonadal germ cell tumors". Publications were included when patients age, location and histology of the germ cell tumor was known. Two double blinded reviewers selected the studies.Results: 141 KS patients with eGCTs were identified. Mean age at presentation was 17.3 years (StDev + - 10.2). In contrast to the extragonadal germ cell tumors in adults, most eGCT in children were mediastinal or in the central nervous system (respectively 90/141; 64% and 23/141; 16% of all tumors). Distribution of histologic subtypes showed that the largest fraction represented a teratoma, mixed-type-non-seminomateus GCT and germinoma, respectively 34/141; 24%, 26/141; 18% and 20/141; 14% of all tumors.

Conclusion

These data suggest a correlation between primary extragonadal germ cell tumors and Klinefelter syndrome. There appears to be an indication for screening on KS in young patients with an eGCT in the mediastinum. A low threshold for radiologic examinations should be considered to discover eGCT. We emphasize the need for genetic analysis in all cases of a male with a mediastinal germ cell tumor for the underdiagnosed Klinefelter syndrome.

Coincidental Central Precocious Puberty and Wilms Tumor in a 5-Year-Old Girl

Wilms tumor is the most frequent pediatric renal malignancy, and its usual presentation is an abdominal mass or hematuria. Unusual presentations have also been reported, such as paraneoplastic syndromes (acquired von Willebrand disease, sudden death due to pulmonary embolism, and Cushing syndrome). These conditions can precede, occur concomitantly, or present in a later phase of tumor development. Precocious puberty, as paraneoplastic endocrine syndrome, has already been described in children with malignant tumors (brain, gonadal, adrenal tumors, and hepatoblastoma). However, little is known about central precocious puberty, as paraneoplastic manifestation of nephroblastoma or secondary to its specific chemotherapy. Here, we report a case of Wilms tumor and simultaneous precocious puberty in a 5-year-old girl. The initial diagnosis was premature telarche, but the clinical and biological pubertal progression changed our diagnosis to idiopathic central precocious puberty. Chemotherapy and nephrectomy were well tolerated, and we began treatment with a gonadotropin-releasing hormone agonist which showed favorable outcomes over the short term. We highlight the need for early diagnosis and work-up in all patients of precocious puberty, in order to institute timely management.

Central precocious puberty as a prelude to hypogonadism in a patient with Klinefelter syndrome

INTRODUCTION

Incomplete pubertal development is a common phenomenon found in patients with Klinefelter syndrome (KFS). KFS combined with central precocious puberty (CPP) rarely occurs. We herein report a rare case of KFS with CPP and review several studies to determine the possible mechanism underlying this condition.

CASE PRESENTATION

An 8-year, 5-month-old male patient was admitted to our hospital because of enlargement of the penis and small testes. Laboratory evaluation revealed high luteinizing hormone and follicle-stimulating hormone levels, a high testosterone level, and the 48,XXYY karyotype. He was treated with triptorelin. One year later, the patient's testosterone level decreased and pubertal arrest occurred.

CONCLUSION

The literature review in this study showed that the occurrence of hypogonadism combined with CPP is not unique to patients with KFS; it has also been reported in individuals with Turner syndrome, adrenal hypoplasia congenita, and other diseases. Such individuals share common features including partial hypogonadism and a normal hypothalamic-pituitary-gonadal axis. CPP is considered a prelude to hypogonadism, and treatment with a gonadotropin-releasing hormone agonist may prevent gonadal failure.

Central precocious puberty as a prelude of gonad dysplasia

There is increasing evidence that patients with gonad dysplasia, as characterized by absent or incomplete puberty, can also exhibit central precocious puberty (CPP). Herein, we review the reported cases that manifest with both gonad dysplasia and CPP. Further, we examine the hypothesis that these patients exhibit a normal hypothalamic-pituitary-gonadal axis, hypogonadism, and the presence of residual gonadal function, and that the onset of disease is related to early initiation of the hypothalamic-pituitary-gonadal axis. Thus, we suggest that CPP is a prelude of some partial hypogonadism.

Klinefelter syndrome in males with germ cell tumors: A report from the Children's Oncology Group

BACKGROUND

Males with Klinefelter syndrome (KS) (47,XXY) may be more likely to develop germ cell tumors (GCTs), particularly mediastinal GCTs. To date, there are no reports characterizing the prevalence of KS among male GCT cases.

METHODS

The authors used array genotyping data from a Children's Oncology Group epidemiology study to estimate the prevalence of KS in males with GCTs (433 males aged birth-19 years). Using Fisher's exact tests, the authors examined differences in age at diagnosis, race/ethnicity, tumor location and histology, and several birth characteristics between cases of KS-GCT and GCT cases without chromosomal abnormalities. Using publicly available data, the authors estimated the 1-year risk, risk ratio, and corresponding 95% confidence interval of GCTs among KS cases.

RESULTS

Based on analysis of array genotyping data, 3% of male GCT cases (13 cases) had KS. The additional X chromosome was of maternal origin in 7 of the 13 cases. Of these 13 KS cases, 5 of 9 KS-GCT cases with parental questionnaire data (56%) reported a diagnosis of KS. No significant differences were observed with regard to patient or birth characteristics between KS-GCT and non-KS-GCT cases. KS-GCT cases were significantly more likely to be diagnosed with mediastinal tumors than non-KS-GCT cases (P<.01). The authors estimated the risk of developing a GCT among males with KS to be 0.00025, or 1 per 4000 males (risk ratio, 18.8; 95% confidence interval, 11.7-30.0).

CONCLUSIONS

Compared with males without chromosomal abnormalities, males with KS are more likely to be diagnosed with a mediastinal GCT. The presence of KS should be considered in males with a diagnosis of mediastinal GCT. In the current study, the authors report that approximately one-third of males with mediastinal germ cell tumors have Klinefelter syndrome, and therefore screening of these individuals for the syndrome may be warranted. Males with Klinefelter syndrome are 19 times as likely as males without Klinefelter syndrome to develop germ cell tumors.

Hematologic Malignancies Associated With Mediastinal Germ Cell Tumors: 10 Years' Experience at Thailand's National Pediatric Tertiary Referral Center

Mediastinal germ cell tumor (MGCT), which accounts for 1% to 3% of extragonadal germ cell tumors, has unique manifestations; it is associated with several types of hematologic malignancy, particularly myeloid neoplasm. The aim of this study was to report the 10-year incidence, clinical characteristics, and outcomes of MGCT at Thailand's national pediatric tertiary referral center. This retrospective study included patients diagnosed with MGCT at the Department of Pediatrics, Siriraj Hospital during 2005 to 2014. Eight patients (all male) were diagnosed with MGCT. Five of 8 patients were found to have hematologic abnormalities. Three patients were diagnosed with acute myeloid leukemia (AML) (one patient with M1, another having M7, and the other with M0). Another patient had mixed MGCT with mediastinal myeloid sarcoma (MMS). The other patient had malignancy-associated hemophagocytic lymphohistiocytosis syndrome (M-HLH). Isochromosome 12p was detected in 3 patients (AML [2], mixed MGCT/MMS [1]). Four of 5 patients with hematologic abnormalities died of hematologic abnormalities or treatment complication (AML [3], M-HLH [1]). One patient with mixed MGCT/MMS survived with chemotherapy. All patients with AML and MMS were nonseminomatous MGCT and the onset of myeloid malignancies were within 1 year after the diagnosis of MGCT. Associated hematologic malignancies should be suspected in MGCT with abnormal blood count or hematologic symptoms. Isochromosome 12p was the most common cytogenetic finding in MGCT-associated myeloid malignancies patients. Those with nonseminomatous MGCT should have their blood count carefully monitored especially during the first year after the diagnosis of MGCT. Better treatment alternatives for MGCT with associated hematologic malignancies are warranted to ameliorate adverse outcomes.

Anatomical and clinical aspects of Klinefelter's syndrome

Klinefelter's syndrome, the most common sex disorder associated with chromosomal aberrations, is characterized by a plethora of clinical features. Parameters for diagnosis of the syndrome are constantly expanding as new anatomical and hormonal abnormalities are noted, yet Klinefelter's remains underdiagnosed and underreported. This review outlines the key anatomical characteristics associated with the syndrome, which are currently used for clinical diagnosis, or may provide means for improving diagnosis in the future. Clin. Anat. 29:606-619, 2016. © 2016 Wiley Periodicals, Inc.

Anti-N-methyl-D-aspartate (anti-NMDA) receptor antibody encephalitis in a male adolescent with a large mediastinal teratoma

We present a case of a 16-year-old boy with Klinefelter syndrome who presented with a syndrome of impaired alertness, orofacial dyskinesias, choreiform movements, epileptic seizures, and autonomic instability, pointing to a diagnosis of anti-N-methyl-Daspartate (anti-NMDA) receptor antibody encephalitis.

It's not all about the testes: medical issues in Klinefelter patients

Important medical conditions associated with Klinefelter syndrome (KS) are categorized as: 1) motor, cognitive, and behavioral dysfunction; 2) tumors; 3) vascular disease; and 4) endocrine/metabolic and autoimmune diseases. Earlier diagnosis of KS may lead to earlier intervention with effective treatment.

Extragonadal mixed germ cell tumor of the right arm: description of the first case in the literature

BACKGROUND

Extragonadal localization of germ cell tumors (GCTs) is rare; to the best of our knowledge, a location in the soft tissue of the arm has never been previously reported in the literature.

CASE PRESENTATION

We report the case of a 37-year-old man who presented with a primary malignant mixed non-seminomatous GCT (teratocarcinoma variety) in the right arm, treated by a combination of cisplatin-based chemotherapy and surgery. After 18 months of close follow-up, no locoregional recurrence or distant metastases have been detected.

CONCLUSIONS

A combination of chemotherapy and surgery is the most appropriate treatment strategy for extragonadal GCTs, to ensure both local and systemic control.

Clinical and hormonal status of infants with nonmosaic XXY karyotype

AIM

To compare our recent findings in a cohort of 77 nonmosaic XXY infants <2 years of age with clinical and biological features already reported.

RESULTS

The majority of reported XXY neonates had normal external genitalia. Only undescended testes and/or micropenis were identified reasons for referral. Delayed ambulation and speech skills were also indications for postnatally karyotyping. All subjects from our cohort (73 prenatally detected subjects, five postnatal diagnoses) had height and weight within the normal range, and were not dysmorphic. Insulin-like-peptide-3 and testosterone secretion by Leydig cells appeared normally sensitive to luteinizing hormone. In reported studies, inhibin B levels were within normal range, anti-Mullerian hormone levels were normal or high and follicle-stimulating hormone (FSH) levels were significantly higher than control values, data consistent with a relative resistance to FSH.

CONCLUSION

Early detection of Klinefelter syndrome is desirable for prospectively monitoring the apparition of developmental problems and the progressive decline in the tubular function of the testis, with the hope of designing future conservative interventions before germ cell degeneration is completed.

Gonadotropin-dependent precocious puberty: neoplastic causes and endocrine considerations

Premature activation of the hypothalamic-pituitary-gonadal (HPG) axis manifests as gonadotropin-dependent precocious puberty. The mechanisms behind HPG activation are complex and a clear etiology for early activation is often not elucidated. Though collectively uncommon, the neoplastic and developmental causes of gonadotropin-dependent precocious puberty are very important to consider, as a delay in diagnosis may lead to adverse patient outcomes. The intent of the current paper is to review the neoplastic and developmental causes of gonadotropin-dependent precocious puberty. We discuss the common CNS lesions and human chorionic gonadotropin-secreting tumors that cause sexual precocity, review the relationship between therapeutic radiation and gonadotropin-dependent precocious puberty, and finally, provide an overview of the therapies available for height preservation in this unique patient population.

Gonadal tumours and DSD

Disorders of sex development (DSD), previously referred to as intersex, has been recognised as one of the main risk factors for development of type II germ cell tumours (GCTs), that is, seminomas/dysgerminomas and non-seminomas (e.g., embryonal carcinoma, yolk sac tumour, choriocarcinoma and teratoma). Within the testis, this type of cancer is the most frequent malignancy in adolescent and young adult Caucasian males. Although these males are not known to have dysgenetic gonads, the similarities in the resulting tumours suggest a common aetiological mechanism(s),--genetically, environmentally or a combination of both. Within the group of DSD patients, being in fact congenital conditions, the risk of malignant transformation of germ cells is highly heterogeneous, depending on a number of parameters, some of which have only recently been identified. Understanding of these recent insights will stimulate further research, with the final aim to develop an informative clinical decision tree for DSD patients, which includes optimal (early) diagnosis without overtreatment, such as prophylactic gonadectomy in the case of a low tumour risk.

The role of the mouse y chromosome on susceptibility to testicular germ cell tumors

Testicular germ cell tumors (TGCT) are sex limited, occurring only in males with a Y chromosome. Recently, the gr/gr deletion on the human Y chromosome was associated with increased risk of TGCTs. In addition, the presence of Y chromosome sequences is associated with TGCTs in cases of gonadal dysgenesis. TGCTs in strain 129 males recapitulate many aspects of testicular cancer in human infants and can be used to evaluate the role of the Y chromosome in TGCT risk. We used chromosome substitution strains and a sex-reversing mutant to test the role of the Y chromosome on TGCT susceptibility. Our results show that a Y-linked gene that does not differ among the tested strains is essential for tumorigenesis.

Tumor risk in disorders of sex development (DSD)

Disorders of sex development (DSD), previously referred to as intersex disorders, comprise a variety of anomalies defined by congenital conditions in which chromosomal, gonadal, or anatomical sex is atypical. Besides issues such as gender assignment, clinical and diagnostic evaluation, surgical and psychosocial management, and sex steroid replacement, the significantly increased risk for developing specific types of malignancies is both clinically and biologically relevant. This relates to germ-cell tumors specifically in DSD patients with hypovirilization or gonadal dysgenesis. The presence of a well-defined part of the Y chromosome (known as the GBY region) is a prerequisite for malignant transformation, for which the testis-specific protein on the Y chromosome (TSPY) is a likely candidate gene. The precursor lesions of these cancers are carcinoma in situ (CIS)/intratubular germ-cell neoplasia unclassified (ITGCNU) in testicular tissue and gonadoblastoma in those without obvious testicular differentiation. Most recently, undifferentiated gonadal tissue (UGT) has been identified as the likely precursor for gonadoblastoma. The availability of markers for the different developmental stages of germ cells allows detailed investigation of the characteristics of normal and (pre)malignant germ cells. Although informative in a diagnostic setting for adult male patients, these markers - such as OCT3/4 - cannot easily distinguish (pre)malignant germ cells from germ cells showing delayed maturation. This latter phenomenon is frequently found in gonads of DSD patients, and may be related to the risk of malignant transformation. Thus, the mere application of these markers might result in over-diagnosis and unnecessary gonadectomy. It is proposed that morphological and histological evaluation of gonadal tissue, in combination with OCT3/4 and TSPY double immunohistochemistry and clinical parameters, is most informative in estimating the risk for germ-cell tumor development in the individual patient, and might in future be used to develop a decision tree for optimal management of patients with DSD.

Extragonadal germ cell tumors: a review with emphasis on pathologic features, clinical prognostic variables, and differential diagnostic considerations

Extragonadal germ cell tumors (GCTs) are relatively uncommon, but represent 1% to 5% of all GCTs. Their morphology varies widely and includes mature teratoma, immature teratoma, seminoma, yolk sac tumor, embryonal carcinoma, choriocarcinoma, and mixed GCTs. Noncentral nervous system extragonadal GCTs are found in a variety of anatomic locations, but most commonly affect the mediastinum and sacrococcygeal region. Predicting behavior in these tumors can be confusing because it is based on a combination of varying factors including patient age, histologic subtype, anatomic site, and clinical stage. This review attempts to dissect these issues by separating the discussion into 3 age groups: neonatal (congenital), children (prepubertal), and adult (postpubertal). Within each individual age group, we cover the significance of anatomic site, morphology, and staging parameters. In addition, we discuss the spectrum of associated secondary malignancies and their impact on patient outcome. Finally, we provide a detailed survey of differential diagnostic considerations grouped by anatomic site.

Management of pineal region tumors

Tumors of the pineal region represent a diverse collection of tumors with a variety of natural histories. This diversity necessitates accurate histologic diagnosis to allow rational therapeutic planning. Evaluation of a pineal lesion should begin with craniospinal MRI and analysis of the cerebrospinal fluid (CSF). Whereas certainty of the histologic diagnosis is now a requirement for treatment in Western nations, some Asian centers continue to recommend a test dose of radiation therapy based on the high incidence of germinoma in those countries. If there is high clinical suspicion of a germinoma or tectal glioma, stereotactic or endoscopic biopsy may be pursued. All other lesions should be referred for open biopsy with microsurgical techniques. This approach provides adequate tissue for diagnosis, may be curative in low-grade tumors, and may substantially improve survival in patients with malignant tumors. If open surgery is not desired by the patient or practitioner, stereotactic or endoscopic biopsy may be followed by radiosurgery for localized, well-demarcated tumors. Radiation therapy is the first-line therapy for germinomas. Although the optimal radiation dosage and volume have not been decided, the current Children's Oncology Group trial may offer definitive evidence to address this dilemma in germ cell tumors. Evidence of CSF seeding requires craniospinal radiation and adjuvant chemotherapy regardless of tumor type. Diagnosis of any of the malignant tumors (non-germ cell tumors, pineoblastomas, and parenchymal tumors of intermediate determination) also requires craniospinal radiation (with local tumor doses of at least 50 Gy) and adjuvant chemotherapy (generally platinum based). Patients with tectal gliomas may undergo excision with or without postoperative radiation; however, they also may be observed with vigilant follow-up alone.