A novel SRY missense mutation affecting nuclear import in a 46,XY female patient with bilateral gonadoblastoma

Patients with disorders of sex development (DSD), especially those with gonadal dysgenesis and hypovirilization, are at risk of developing the so-called type II germ cell tumors (GCTs). Both carcinoma in situ and gonadoblastoma (GB) can be the precursor lesion, resulting in a seminomatous or non-seminomatous invasive cancer. SRY mutations residing in the HMG domain are found in 10–15% of 46,XY gonadal dysgenesis cases. This domain contains two nuclear localization signals (NLSs). In this study, we report a unique case of a phenotypical normal woman, diagnosed as a patient with 46,XY gonadal dysgenesis, with an NLS missense mutation, on the basis of the histological diagnosis of a unilateral GB. The normal role of SRY in gonadal development is the upregulation of SOX9 expression. The premalignant lesion of the initially removed gonad was positive for OCT3/4, TSPY and stem cell factor in germ cells, and for FOXL2 in the stromal component (ie, granulosa cells), but not for SOX9. On the basis of these findings, prophylactical gonadectomy of the other gonad was performed, also showing a GB lesion positive for both FOXL2 (ovary) and SOX9 (testis). The identified W70L mutation in the SRY gene resulted in a 50% reduction in the nuclear accumulation of the mutant protein compared with wild type. This likely explains the diminished SOX9 expression, and therefore the lack of proper Sertoli cell differentiation during development. This case shows the value of the proper diagnosis of human GCTs in identification of patients with DSD, which allows subsequent early diagnosis and prevention of the development of an invasive cancer, likely to be treated by chemotherapy at young age.     

Ultrastructure of fetal human gonad before sexual differentiation and during early testicular and ovarian development

The development of the human gonad was investigated by light and transmission electron microscopy in 20 embryos and fetuses between 4.5 and 11.5 weeks of gestation, i.e. during the stages of sex-indifferent gonad, initial testicular and ovarian development. The gonadal blastema in 4.5-week-old embryos appeared formed by poorly differentiated somatic mesothelial cells, and by specialized germ cells (PGCs) with signs of ameboidism, cellular structures suggesting active protein biosynthesis and mitotic activity. The sexual differentiation of the gonads was clearly observed in 7-week-old embryos and involved at the same time the testis and the ovary. The former contained seminiferous cords formed by palisades of poorly differentiated Sertoli cells, which were segregated from the mesothelium by a rudimentary albuginea. The interstitial tissue at this age contained mesenchymal cells. Between 8 and 11.5 weeks of gestation, there was a synchronous cytodifferentiation of both Sertoli and Leydig cells. The latter acquired features of steroidogenic elements. The ovaries of 7-week-old fetuses contained packed ovigerous cords formed by somatic and germ cells (oogonia). The former embraced the oogonia with thin overlapping cytoplasm projections, and acquired features similar to those of cells in primary follicles, already at this early fetal age. At the same time the sexual differentiation of the gonads involved somatic and germ cells. In the female, the oogonia continued to show the main features they had during migration and colonization, including a high mitotic rate, signs of ameboidism and a developed apparatus for protein synthesis. On the contrary Gonocytes enclosed in the seminiferous cords progressively entered a quiescent phase characterized by a reduced mitotic rate, a decrease of endoplasmic reticulum and nucleolar complexity. The chronological relationship between the cytodifferentiation of Sertoli and Leydig cells, and changes of germ cells, suggest that somatic components of the testis may contribute to a male type of differentiation of germ cells from the very beginning of sexual differentiation.     

Carcinoma in situ, gonadoblastoma, and early invasive neoplasia in a nine-year-old girl with 46,XY gonadal dysgenesis.

Carcinoma in situ (CIS), gonadoblastoma, and early invasive neoplasia were detected in the dysgenetic gonad of a nine-year-old girl with 46,XY gonadal dysgenesis. A close relationship between the three neoplastic components was supported by morphological and immunohistochemical studies. Our findings support the hypothesis that all germ cell tumours, including gonadoblastomas, originate from CIS germ cells formed during early embryonic life.     

Intratubular germ cell neoplasia of unclassified type occupying the whole testis accompanied by a small mature teratoma and metastatic choriocarcinoma and Sertoli cell-only tubules in the other testis

A 19-year-old man with mild mental retardation was diagnosed as having metastatic choriocarcinoma and a testicular tumor. Histopathological examination of the resected testis revealed the presence of a small lesion of mature teratoma but no trace of choriocarcinoma. The remaining seminiferous tubules were atrophic and lined by large atypical germ cells, which were diagnosed as intratubular germ cell neoplasia of the unclassified type (IGCNU). A small area with prominent tubules was also observed. Within this lesion, the tubules were dilated and contained several layers of cells with central necrosis. Immunohistological comparison of staining for several biological markers (Ki-67, c-kit and placental alkaline phosphatase) between cells in the atrophic tubules and those in the dilated tubules indicated a progression of the latter cells to cells with a more proliferative ability. In the opposite testis, examined at autopsy after death due to metastatic choriocarcinoma, all seminiferous tubules were lined by Sertoli cells only. It was therefore assumed that the germ cell tumor of the combined histological type had primarily arisen in the background of IGCNU, and that choriocarcinoma had spontaneously regressed. The early onset of these testicular neoplastic lesions strongly indicates their occurrence under the genetic background of gonadal dysplasia, the Sertoli cell-only syndrome. The possible relation of gonadal disease to mental retardation in this patient is also discussed.     

True hermaphroditism and mixed gonadal dysgenesis in young children: a clinicopathologic study of 10 cases.

True hermaphroditism (TH) refers to individuals who have both unequivocal ovarian tissue and testicular elements regardless of their karyotypes; whereas mixed gonadal dysgenesis (MGD) refers to individuals who usually have a differentiated gonad on one side and a streak gonad or streak testis on the other side. A differential diagnosis between the TH and MGD has important clinical implications for gender assignment and the decision for early gonadectomy; however, variable clinical and histological features frequently lead to the confusion of TH with MGD. We reviewed the clinicopathological features of TH (n = 4) and MGD (n = 6) in young children to identify which morphological features are important for a differential diagnosis between the two conditions. In both conditions, the testicular compartment was composed of immature seminiferous tubules lined by immature Sertoli cells and primitive germ cells; this finding was not helpful for a differential diagnosis. The ovarian compartment in TH cases showed numerous primordial follicles containing primary oocytes with a few primary or antral follicles; however, ovarian compartments in patients with MGD were characterized by primitive sex-cordlike structures with or without germ cell components within the ovarian-type stroma, mimicking gonadoblastomas in two cases and granulosa cell or Sertoli cell tumors in three cases. Hormonal profiles, cytogenetic results, and an internal duct system were not helpful in a differential diagnosis. In conclusion, a differential diagnosis between TH and MGD is largely dependent on the histological features of the gonads. Therefore, examination of all resected or biopsied tissue and the application of strict histological criteria are important.     

Differentiation of mammalian embryonic gonad

Formation and differentiation of a gonad depend on finely controlled interactions between germ cells and various types of somatic cells. These interactions already begin when the germ cells start migrating toward the gonadal ridge. Reaching the presumptive gonadal area on the mesonephros, the germ cells join with the mesonephric-derived cells. These mesonephric cells are probably the precursors of the steroid-producing cells. A crucial event for gonadal function is the enclosure of germ cells and somatic cells in specific germ cell compartments. Survival and differentiation of the germ cells depend on this separation. Differentiation of the steroid-producing cells depends in turn on remaining outside the cell compartments. The mechanisms directing the gonad to develop into a testis or an ovary are still obscure, but specific gene products from the sex chromosomes probably play a basic role in gonadal sex differentiation.     

Role of chromosomal imbalances in the pathogenesis of DSD: A retrospective analysis of 115 prenatal samples

Differences of sex development (DSDs) are a group of congenital conditions characterized by a discrepancy between chromosomal, gonadal, and genital sex development of an individual, with significant impact on medical, psychological and reproductive life. The genetic heterogeneity of DSDs complicates the diagnosis and almost half of the patients remains undiagnosed. In this context, chromosomal imbalances in syndromic DSD patients may help to identify new genes implicated in DSDs. In this study, we aimed at describing the burden of chromosomal imbalances including submicroscopic ones (copy number variants or CNVs) in a cohort of prenatal syndromic DSD patients, and review their role in DSDs. Our patients carried at least one pathogenic or likely pathogenic chromosomal imbalance/CNV or low-level mosaicism for aneuploidy. Almost half of the cases resulted from an unbalanced chromosomal rearrangement. Chromosome 9p/q, 4p/q, 3q and 11q anomalies were more frequently observed. Review of the literature confirmed the causative role of CNVs in DSDs, either in disruption of known DSD-causing genes (SOX9, NR0B1, NR5A1, AR, ATRX, …) or as a tool to suspect new genes in DSDs (HOXD cluster, ADCY2, EMX2, CAMK1D, …). Recurrent CNVs of regulatory elements without coding sequence content (i.e. duplications/deletions upstream of SOX3 or SOX9) confirm detection of CNVs as a mean to explore our non-coding genome. Thus, CNV detection remains a powerful tool to explore undiagnosed DSDs, either through routine techniques or through emerging technologies such as long-read whole genome sequencing or optical genome mapping.     

Inhibin-alpha CD99, HEA125, PLAP, and chromogranin immunoreactivity in testicular neoplasms and the androgen insensitivity syndrome

We investigated 115 testicular and 3 epididymal tumors and 6 cases of the complete androgen insensitivity syndrome (AIS) for the expression of inhibin-alpha, CD99, HEA125, PLAP, and chromogranin, using monoclonal antibodies and standard immunhistochemical techniques. Ihibin-alpha was detected in the neoplastic cells in 27 of 27 primary Leydig cell tumors (LCTs), 1 of 1 metastatic LCT, 6 of 20 Sertoli cell tumors (SCTs), 4 of 5 juvenile granulosa cell tumors (GCTs), and 2 of 5 unclassified sex cord-stromal tumors (USCSTs). Except for 2 choriocarcinomas, the choriocarcinomatous component of 1 mixed germ cell tumor, and a small focus of inhibin-positive syncytiotrophoblast in 1 embryonal carcinoma, inhibin-a immunoreactivity was not present in the neoplastic cells of the 38 remaining testicular germ cell tumors; 11 B-cell and 1 T-cell lymphomas; 1 granulocytic sarcoma; and 1 rhabdomyosarcoma of the testis; 1 adenoma of the rete testis, and 3 adenomatoid tumors of the epididymis. Inhibin-alpha immunoreactivity was present in the Sertoli cells and Leydig cells in 5 testicular hamartomas and in 1 Sertoli cell adenoma in 6 cases of AIS; both Sertoli and Leydig cells were also positive in the extranodular testicular parenchyma present in 2 of these cases. CD99 was detected in 10 of 15 primary LCTs, 1 of 7 SCTs, 3 of 5 JGCTs, and in 1 of 5 USCSTs but was not found in any tumor outside the sex cord-stromal category. HEA125 immunostaining was not detected in sex cord-stromal tumors; however, 3 of 12 seminomas, 3 of 12 embryonal carcinomas, 6 of 8 yolk sac tumors, and 1 of 2 teratomas were HEA125 positive. PLAP was not detected in sex cord-stromal tumors except for 4 of 15 primary LCTs but was present in most germ cell tumors. Chromogranin immunostaining was present in the sex cord-like element in 1 of 5 USCSTs, 1 of 8 YSTs, 1 of 2 teratomas, and in 1 of 1 rete adenoma, and in normal adjacent rete testis. In conclusion, although inhibin-alpha and PLAP, and, to a somewhat lesser extent, CD99 and HEA125 immunostaining are helpful in the differential diagnosis of certain testicular neoplasms that are difficult to distinguish on morphologic grounds, chromogranin is far less helpful in this context.     

Developmental regulation of connexin 43 expression in fetal mouse testicular cells

Multiple connexins have been identified in testicular cells. Several lines of evidences indicate that, among them, connexin 43 (Cx43) may be unique for control of gonad development and spermatogenesis. To date, however, it is not known whether Cx43 is expressed in the fetal testis and what possible types of cellular interactions mediated by this connexin are critical to male fertility. In the present work, expression of Cx43 was investigated at various developmental ages in cryosections from mouse testis by using specific antibodies against Cx43. In serial or double-labeled sections, Cx43 localization was compared with immunocytochemical distribution of steroidogenic enzyme, 3beta-hydroxysteroid dehydrogenase (3betaHSD), Mullerian inhibitory hormone (MIH), and germinal nuclear cell antigen (GCNA1), which are specific markers, respectively, of interstitial Leydig, Sertoli, and germinal cells. Sections were analyzed by fluorescence microscopy. We found that Cx43 immunofluorescence (IF) was uniformly distributed in the undifferentiated gonad at 11.5 days post coitus (dpc) and in cells of the mesonephric tubules. In the undifferentiated gonad, Cx43 was localized between primordial germ cells and somatic cells. At 12.5 dpc, when the gonad has undergone sexual differentiation, in the interstitium Cx43 was localized in Leydig cells and in the seminiferous cord it was localized between adjacent Sertoli cells. In Leydig and Sertoli cells, Cx43 labeling increased at 14.5, 16.5, and 18.5 dpc. From day 12.5 up to 18.5 dpc, Cx43 was also localized in cell borders between germinal and Sertoli cells. In conclusion, this study demonstrates that from the earliest stages of gonadal development, Cx43 is expressed in the principal cell types that participate in the control of male fertility. It also shows that Cx43 expression in Leydig and Sertoli cells increase during fetal life. Finally, it provides evidence that, throughout embryonic life, Cx43 forms gap junctions between Sertoli and germinal cells.     

Mammalian sex determination—insights from humans and mice

Disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Many of the genes required for gonad development have been identified by analysis of DSD patients. However, the use of knockout and transgenic mouse strains have contributed enormously to the study of gonad gene function and interactions within the development network. Although the genetic basis of mammalian sex determination and differentiation has advanced considerably in recent years, a majority of 46,XY gonadal dysgenesis patients still cannot be provided with an accurate diagnosis. Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. Here, we review our current knowledge of mammalian sex determination drawing on insights from human DSD patients and mouse models.     

The World Health Organization 2016 classification of testicular non‐germ cell tumours: a review and update from the International Society of Urological Pathology Testis Consultation Panel

The World Health Organization (WHO) released a new tumour classification for the genitourinary system in early 2016 after consensus by pathologists with expertise in these organs. It utilized the framework of the 2004 classification, and incorporated the most up‐to‐date information concerning these tumours. In testicular tumours, the majority of the changes occurred in the nomenclature and classification of germ cell tumours; however, several modifications were also made for non‐germ cell tumours. Among sex cord–stromal tumours, sclerosing Sertoli cell tumour (SCT) is no longer recognized as a separate entity but as a morphological variant of SCT not otherwise specified (NOS), as CTNNB1 gene mutations have been noted in both neoplasms but not in the other forms of SCT. Similarly, the lipid cell variant is not separately classified, but is considered to be a morphological variant of SCT NOS. Large‐cell calcifying SCT is recognized as a distinct entity that occurs either sporadically or in association with Carney complex, with the latter patients having a distinct germline PRKAR1A gene mutation. Intratubular large‐cell hyalinizing Sertoli cell neoplasia is also accepted as a separate entity linked with Peutz–Jeghers syndrome. The subcategories of ‘mixed’ and ‘incompletely differentiated’ forms of sex cord/gonadal stromal tumours have been replaced by ‘mixed and unclassified sex cord–stromal tumours’. New entities introduced in the latest WHO revision include: myoid gonadal stromal tumour and ‘undifferentiated gonadal tissue’, a putative precursor lesion of gonadoblastoma, whereas juvenile xanthogranuloma and haemangioma are included in the miscellaneous category of tumours.     

Immunohistochemical study of Sertoli-stromal cell tumor; comparison between the tumor arising from the gonad of a testicular feminization syndrome bearing patient and from ovaries of non-bearing patients

The association of Sertoli-stromal cell tumor with testicular feminization syndrome (TFS) has been elaborated in the past studies. Here, we described immunohistochemical studies on Sertoli cell tumor of the gonad in a TFS patient and compare with 2 other cases of spontaneous ovarian Sertoli-stromal tumor. [Case 1] The case was a 73 year-old Japanese patient (46XY karyotype), who had had primary amenorrhea. High level of testosterone was noted in laboratory investigation (1900 ng/ml). No ambiguous morphology of external genitalia was present, but atrophy of vagina was noted. The patient was diagnosed as TFS. A left gonadal tumor was identified histologically showing well differentiated Sertoli cell tumor. The tumor cells were positive for anti-vimentin antibody but negative for anti-keratin, EMA and p53 antibodies by immunohistochemistry. The right gonad was an immature testis. [Case 2] The case was a 33 year-old female with ovarian Sertoli-Leydig cell tumor. Immunohistochemically, positive reaction for anti-keratin and p53 antibodies were observed. [Case 3] The case was a 17 year-old female with moderately differentiated Sertoli cell tumor of the ovary. The tumor cells were positive for anti-keratin, EMA and p53 antibodies by immunohistochemistry. Difference in immunohistochemical reactions between Sertoli cell tumor in TFS and Sertoli-stromal cell tumors of the ovaries was probably due to variation in the degree of gonadal development.     

Whole exome sequencing combined with linkage analysis identifies a novel 3?bp deletion in NR5A1

Disorders of sex development (DSDs) encompass a broad spectrum of conditions affecting the development of the gonads and genitalia. The underlying causes for DSDs include gain or loss of function variants in genes responsible for gonad development or steroidogenesis. Most patients with DSD have an unknown genetic etiology and cannot be given an accurate diagnosis. We used whole exome capture and massively parallel sequencing to analyse a large family with 46,XY DSD and 46,XX premature ovarian insufficiency. In addition, we used a recently developed method for linkage analysis using genotypes extracted from the MPS data. This approach identified a unique linkage peak on chromosome 9 and a novel, 3 bp, in-frame deletion in exon six of NR5A1 (steroidogenic factor-1 or SF1) in all affected individuals. We confirmed that the variant disrupts the SF1 protein and its ability to bind and regulate downstream genes. NR5A1 has key roles at multiple points in gonad development and steroidogenic pathways. The variant described here affects the function of SF1 in early testis development and later ovarian function, ultimately leading to the 46,XY DSD and 46,XX premature ovarian insufficiency phenotypes, respectively. This study shows that even at low coverage, whole exome sequencing, when combined with linkage analysis, can be a powerful tool to identify rapidly the disease-causing variant in large pedigrees.     

Dysgerminoma in Turner's syndrome.

The importance of the Y-chromosome for the germ cell tumour development in gonadal dysgenesis has been emphasized many times. In contrast, only two cases of dysgerminoma or gonadoblastoma had been published so far in the XO-Turner's syndrome. With this report, another case of Turner's syndrome developing a dysgerminoma in a gonadal streak is presented. No Y-chromosome containing stemline could be detected in the patient nor in the tumour. A primary genetic etiology or a mechanism related to early secondary regression or dysgenesis of the gonad are discussed as causative factors in germ cell tumour development within gonadal streaks.     

Accelerated germ cell apoptosis in sex chromosome aneuploid fetal human gonads

The purpose of the study was to examine the occurrence of programmed cell death (apoptosis) in normal and chromosomally aneuploid testis and ovaries during the second trimester of human development. Such information may be useful in understanding normal and abnormal germ cell development and disorders associated with infertility in adult life. Apoptosis was studied by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) analysis in human fetal ovaries (n = 16) and testis (n = 14) between 9 and 23 weeks of development, in ovaries of four Turner's syndrome fetuses (45X) and in the gonad of an XO/XY fetus. In normal fetal testis, a small proportion of germ cells, Sertoli cells and Leydig cells undergo apoptosis. In normal fetal ovaries, some developing oocytes and granulosa cells were detected as TUNEL positive. Semiquantitative analysis of fetal ovaries revealed that approximately 3-7% of oocytes were apoptotic. In abnormal fetal testis (XO/XY genotype). TUNEL analysis revealed that only germ cells not enclosed in seminiferous tubules undergo apoptosis. TUNEL analysis of the Turner's syndrome (45X) ovaries studied at 15 and 20 weeks of development revealed massive apoptosis of the oocytes. Nearly 50-70% of the oocytes were TUNEL positive in these ovaries. These results suggest that germ cell apoptosis is a common event occurring during development of human gonads. Chromosomal defects by some means accelerates apoptosis that probably leads to gonadal dysgenesis later in life.     

Detection of Y-chromosome in gonadal tumours using fluorescence in situ hybridization: diagnostic value in intersex conditions including older patients with clinically unsuspected androgen insensitivity syndrome

Aims:  To evaluate fluorescence in situ hybridization (FISH) for SRY , the testis-determining gene on the Y-chromosome, in gonadal specimens from patients with intersex disorders including two older individuals presenting with Sertoli cell adenomas and clinically unsuspected androgen insensitivity syndrome (AIS).
Methods and results:  FISH, using probes for SRY and the X-centromere, was performed on two Sertoli cell adenomas presenting as ovarian masses in phenotypic females aged 62 and 73 years with previously undiagnosed AIS. Gonadal biopsies and tumours from eight additional patients with known intersex disorders and XY phenotype were also studied. Signal for SRY was demonstrated in at least one specimen from all patients, and from 16/18 (89%) specimens overall. The specificity of FISH was determined by analysis of 10 sporadic ovarian tumours including six dysgerminomas and four Sertoli-Leydig cell tumours: all cases expressed a female XX chromosomal signal.
Conclusions:  The demonstration of SRY using FISH is useful in the assessment of gonadal specimens from patients with intersex disorders, particularly in older individuals where the diagnosis may be unsuspected clinically. However, it may be necessary to examine multiple specimens in some cases to confirm the presence of Y-chromosomal material.     

Atypical development of Sertoli cells and impairment of spermatogenesis in the hypogonadal (hpg) mouse

Testes of hypogonadal (hpg) mice show arrested postnatal development due to congenital deficiencies of gonadotrophin-releasing hormone (GnRH) and gonadotrophin synthesis and secretion. Follicle-stimulating hormone (FSH), androgen or oestrogen treatment restore qualitatively normal spermatogenesis in hpg testes. Understanding the cellular and molecular changes accompanying hormone-induced spermatogenesis in hpg mice requires detailed morphological analyses of the germ cells and Sertoli cells in the untreated hpg testis. We compared seminiferous epithelial cytology in adult hpg, immature and adult wild-type mice using unbiased optical disector-based stereology, immunolocalization of Sertoli cell microtubules (MT), espin (a component of the blood-testis barrier), markers of Sertoli cell maturity (p27(kip1) and WT-1), and electron microscopy. Hpg testes had marked reductions in weight, seminiferous cord volume and length, and severe spermatogenic impairment with germ cells per testis < 1% of adult wild-type testes. Sertoli cell nuclei expressed WT-1 in hpg testes, but often were centrally located, similar to 9-14-day-old wild-type testes, and they expressed p27(kip1), indicating that hpg Sertoli cells were post-mitotic. Hpg testes had significantly (P < 0.05) reduced Sertoli cells per testis (0.56 million) compared with 10-day wild-type (1.15 million) and adult wild-type testes (2.06 million). Immunofluorescence labelling of normal adult Sertoli cells showed supranuclear MT columns and basally located espin, but these features were absent in 10-day-old and hpg Sertoli cells. Hpg Sertoli cells showed pleomorphic nuclear ultrastructure with mature-type nucleoli, similar to normal adult-type Sertoli cells, but hpg Sertoli cells exhibited incomplete tight junctions that lacked ectoplasmic specializations. We conclude that in hpg mice, chronic gonadotrophin insufficiency restrains Sertoli cell proliferation and maturation, forming pseudo-adult-type Sertoli cells that are incapable of supporting germ cell proliferation and maturation.