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Background Methods and Results Conclusions Knowledge regarding adenocarcinoma of the rete testis (ACRT) is extremely limited due to its scarcity.This study enrolled 18 patients with ACRT from multiple institutions. Clinicopathological and immunohistochemical features were investigated, together with a comprehensive review of 95 previously reported cases. One case was assessed using next‐generation sequencing (NGS). The median age of the patient cohort was 54 years (range = 20–69 years), with the majority presenting with a testicular mass (13 of 18); predominantly right‐sided (11 of 18). Six patients died within the second year following diagnosis. The morphology of ACRT spans a wide spectrum, including newly identified mucinous carcinoid‐like features, with mucous cells floating in mucus and signet‐ring cells. Notably, transition from a benign to a malignant rete epithelium was noted in 38.9% of cases (seven of 18). Immunohistochemically, tumour cells most frequently showed strong positivity for CK7 (12 of 16) and CK20 (10 of 17), with occasionally positivity for calretinin (three of 16), WT‐1 (two of 17) and PAX‐8 (two of 15). According to NGS in a single case, MET was amplified, leading to the patient benefiting from mesenchymal–epidermal transition factor (MET) inhibitors. Furthermore, MET amplification was assessed in 13 cases using fluorescence in‐situ hybridisation and detected in two cases (15.4%). No significant correlation between MET amplification and mesenchymal–epidermal transition factor (MET) levels was observed in the cases studied.Primary ACRT is a rare malignant tumour which poses a diagnostic challenge, and is associated with poor prognosis. Cases of ACRT with MET amplification might represent promising candidates for the treatment with MET inhibitors. [ABSTRACT FROM AUTHOR]

Spermatogonial stem cells originate from gonocytes and undergo self-renewal and differentiation to generate mature spermatozoa via spermatogenesis in the seminiferous tubules of the testis in male mammals. Owing to the unique capacity of these cells, the spermatogonial stem cell transplantation technique, which enables the restoration of male fertility by transfer of germlines between donor and recipient males, has been developed. Thus, spermatogonial stem cell transplantation can be used as an important next-generation reproductive and breeding tool in livestock production. However, in large animals, this approach is associated with many technical limitations and inefficiency. Furthermore, research regrading spermatogonial stem cell transplantation in stallions is limited. Therefore, this review article describes the history and current knowledge regarding spermatogonial stem cell transplantation in animals and challenges in establishing an experimental protocol for successful spermatogonial stem cell transplantation in stallions, which have been presented under the following heads: spermatogonial stem cell isolation, recipient preparation, and spermatogonial stem cell transplantation. Additionally, we suggest that further investigation based on previous unequivocal evidence regarding donor-derived spermatogenesis in large animals must be conducted. A detailed and better understanding of the physical and physiological aspects is required to discuss the current status of this technique field and develop future directions for the establishment of spermatogonial stem cell transplantation in stallions.

Aquaporins (AQPs), also known as water channels, appear to be particularly promising in maintaining male reproductive potential. Therefore, this study aimed to determine the presence of classical AQPs in the bovine (Bos taurus) reproductive system and analyze changes in their expression with age using immunohistochemistry and Western blotting. Of the six classical AQPs, AQP0, AQP1, AQP4, AQP5 and AQP6 were detected, while AQP2 was absent. In the testis, AQP0 was visible in Leydig cells in selected animals, while AQP1 was found in myoid cells surrounding the seminiferous tubules of mature individuals. This characteristic expression patterns of AQP0, limited only to certain bulls, is difficult to explain unequivocally. It is possible that AQP0 expression in cattle is subject to individual variability or changes in response to specific physiological conditions. In the caput and corpus epididymis, AQP0 showed weak expression in epithelial cells of immature animals and stronger expression in basal and principal cells of reproductive bulls. In all animals, AQP1 was present on the apical surface of epithelial cells in the initial segment of the caput epididymis. AQP4, AQP5 and AQP6 were identified in principal and basal cells along the entire epididymis of reproductive bulls. The abundance of AQP4 and AQP6 increased from the caput to the cauda epididymis with the growth and development of the animals. In all males, AQP4, AQP5 and AQP6 were observed in epithelial cells of the vas deferens, and their expression in this section increased with age. In conclusion, the abundance and distribution of the classical AQPs in various cell types and parts of the male reproductive system indicate their crucial role in maintaining water homeostasis, which is essential for normal reproductive function in cattle. [ABSTRACT FROM AUTHOR]

Tubular ectasia of the rete testis (TERT) presents as multiple cystic structures within the rete testis, often incidentally detected on ultrasound as echo-free intratesticular cystic lesions. Despite its benign nature, assessing testicular cystic lesions can sometimes be challenging. The primary importance of identifying this uncommon condition lies in its distinction from cystic testicular malignancies and thus avoiding further radical procedures. We report an instance of TERT within the right testis discovered incidentally in a patient with a medical background of epididymitis, presenting for management of left testis cryptorchidism, and bilateral inguinal hernia.

Carcinoma of rete testis is an extremely rare malignant tumor arising from its epithelium. Prognosis is poor with mean survival of 8 months. Lymph node metastases and the size of the tumor larger than 5 cm are poor prognostic factors. We report a case of primary undifferentiated carcinoma of the rete testis in a 46-year-old man who presented with testicular enlargement without previous trauma or cryptorchidism, and with extensive peritoneal carcinomatosis, retroperitoneal lymph node metastases and fatal outcome. We present this case because of the rarity of the carcinoma of the rete testis and its challenging diagnosis.

The androgen pathway via androgen receptor (AR) has received the most attention for development of male reproductive tracts. The estrogen pathway through estrogen receptor (ESR1) is also a major contributor to rete testis and efferent duct formation, but the role of progesterone via progesterone receptor (PGR) has largely been overlooked. Expression patterns of these receptors in the mesonephric tubules (MTs) and Wolffian duct (WD), which differentiate into the efferent ductules and epididymis, respectively, remain unclear because of the difficulty in distinguishing each region of the tracts. This study investigated AR, ESR1, and PGR expressions in the murine mesonephros using three-dimensional (3-D) reconstruction. The receptors were localized in serial paraffin sections of the mouse testis and mesonephros by immunohistochemistry on embryonic days (E) 12.5, 15.5, and 18.5. Specific regions of the developing MTs and WD were determined by 3-D reconstruction using Amira software. AR was found first in the specific portion of the MTs near the MT-rete junction at E12.5, and the epithelial expression showed increasing strength from cranial to the caudal regions. Epithelial expression of ESR1 was found in the cranial WD and MTs near the WD first at E15.5. PGR was weakly positive only in the MTs and cranial WD starting on E15.5. This 3-D analysis suggests that gonadal androgen acts first on the MTs near the MT-rete junction but that estrogen is the first to influence MTs near the WD, while potential PGR activity is delayed and limited to the epithelium. [ABSTRACT FROM AUTHOR]

Polysialic acid (polySia) is a carbohydrate polymer that modulates several cellular processes, such as migration, proliferation and differentiation processes. In the brain, its essential impact during postnatal development is well known. However, in most other polySia positive organs, only its localization has been described so far. For instance, in the murine epididymis, smooth muscle cells of the epididymal duct are polysialylated during the first 2 weeks of postnatal development. To understand the role of polySia during the development of the epididymis, the consequences of its loss were investigated in postnatal polySia knockout mice. As expected, no polysialylation was visible in the absence of the polysialyltransferases ST8SiaII and ST8SiaIV. Interestingly, cGMP-dependent protein kinase I (PGK1), which is essentially involved in smooth muscle cell relaxation, was not detectable in peritubular smooth muscle cells when tissue sections of polySia knockout mice were analyzed by immunohistochemistry. In contrast to this signaling molecule, the structural proteins smooth muscle actin (SMA) and calponin were expressed. As shown before, in the duct system of the testis, even the expression of these structural proteins was impaired due to the loss of polySia. We now found that the rete testis, connecting the duct system of the testis and epididymis, was extensively dilated. The obtained data suggest that less differentiated smooth muscle cells of the testis and epididymis result in disturbed contractility and thus, fluid transport within the duct system visible in the enlarged rete testis. [ABSTRACT FROM AUTHOR]

Polysialic acid (polySia) is a carbohydrate polymer that modulates several cellular processes, such as migration, proliferation and differentiation processes. In the brain, its essential impact during postnatal development is well known. However, in most other polySia positive organs, only its localization has been described so far. For instance, in the murine epididymis, smooth muscle cells of the epididymal duct are polysialylated during the first 2 weeks of postnatal development. To understand the role of polySia during the development of the epididymis, the consequences of its loss were investigated in postnatal polySia knockout mice. As expected, no polysialylation was visible in the absence of the polysialyltransferases ST8SiaII and ST8SiaIV. Interestingly, cGMP-dependent protein kinase I (PGK1), which is essentially involved in smooth muscle cell relaxation, was not detectable in peritubular smooth muscle cells when tissue sections of polySia knockout mice were analyzed by immunohistochemistry. In contrast to this signaling molecule, the structural proteins smooth muscle actin (SMA) and calponin were expressed. As shown before, in the duct system of the testis, even the expression of these structural proteins was impaired due to the loss of polySia. We now found that the rete testis, connecting the duct system of the testis and epididymis, was extensively dilated. The obtained data suggest that less differentiated smooth muscle cells of the testis and epididymis result in disturbed contractility and thus, fluid transport within the duct system visible in the enlarged rete testis.

Understanding squamate reproductive morphology is crucial for investigating ecological, behavioral, and evolutionary questions. Here, we describe the anatomy and histology of the male genital system of Ameiva ameiva from southeastern Brazil. Ten adult males were dissected to characterize genital macroscopy and collect fragments of the testes, gonadoducts, and kidneys for histological examination. We examined 10 transverse histological sections per individual and measured the epithelial height of the epididymis and ductus deferens. The male reproductive system consists of a pair of yellowish oval testes, the rete testis, ductuli efferentes, epididymis, ductus deferens, ampulla ductus deferentis, sexual segment of the kidney (SSK), cloaca, and hemipenis. The hemipenis is elongated, cylindrical, and unilobed, with a sulcate face and an asulcate face, which has continuous fringes throughout its length. Seminiferous tubules exhibited germ cells at various stages. The epididymis is wider and more coiled than the ductus deferens. The rete testis has a simple squamous epithelium with long stereocilia, while the narrower ductuli efferentes are lined by a simple ciliated cuboidal epithelium. The epididymal epithelium is pseudostratified columnar, with basal and ciliated principal cells, whereas the ductus deferens epithelium is pseudostratified to simple cuboidal. The epididymal epithelium is 1.5 times taller than the ductus deferens epithelium. Here, we observed the SSK present in the cortex of the ventral region of the kidneys due to the hypertrophy of the distal convoluted tubules, as well as its secretory activity. Our findings will contribute to future research into the evolution of squamate reproductive morphology., (© 2024 American Association for Anatomy.)

Cystic dysplasia of the rete testis is a rare benign abnormality seen in the pediatric population. Diagnosed by scrotal ultrasonography, this lesion is often associated with congenital renal tract anomalies, most commonly ipsilateral renal agenesis or multicystic dysplastic kidney. Treatment traditionally involves orchiectomy or testicular sparing surgery; however, conservative treatment with surveillance has been used as an appropriate alternative. We present the case of a 5-year-old boy with cystic dysplasia of the rete testis with associated unilateral renal agenesis.

Cystic dysplasia of the rete testis (CDRT) is a rare cause of testicular masses in children. The pathogenesis of this malformation remains unclear. It is often associated with other genitourinary anomalies, commonly presenting as agenesis or dysplasia of the ipsilateral kidney. A case involving a 9-year-old boy with a testicular lesion and ipsilateral renal agenesis, who was diagnosed with CDRT after histological examination, is reported. In addition, a systematic review of the literature was performed to better understand this pathology to design the most appropriate treatment and follow-up strategy for patients with CDRT.

Numb (Nb) and Numb-like (Nbl) are functionally redundant adaptor proteins that critically regulate cell fate and morphogenesis in a variety of organs. We selectively deleted Nb and Nbl in testicular germ cells by breeding Nb/Nbl floxed mice with a transgenic mouse line Tex101-Cre. The mutant mice developed unilateral or bilateral cystic dilation in the rete testis (RT). Dye trace indicated partial blockages in the testicular hilum. Morphological and immunohistochemical evaluations revealed that the lining epithelium of the cysts possessed similar characteristics of RT epithelium, suggesting that the cyst originated from dilation of the RT lumen. Spermatogenesis and the efferent ducts were unaffected. In comparisons of isolated germ cells from mutants to control mice, the Notch activity considerably increased and the expression of Notch target gene Hey1 significantly elevated. Further studies identified that germ cell Fgf4 expression negatively correlated the Notch activity and demonstrated that blockade of FGF receptors mediated FGF4 signaling induced enlargement of the RT lumen in vitro. The crucial role of the FGF4 signaling in modulation of RT development was verified by the selective germ cell Fgf4 ablation, which displayed a phenotype similar to that of germ cell Nb/Nbl null mutant males. These findings indicate that aberrant over-activation of the Notch signaling in germ cells due to Nb/Nbl abrogation impairs the RT development, which is through the suppressing germ cell Fgf4 expression. The present study uncovers the presence of a lumicrine signal pathway in which secreted/diffusible protein FGF4 produced by germ cells is essential for normal RT development. [ABSTRACT FROM AUTHOR]

Abstract Background Seminoma accounts for 30–50% of testicular germ cell tumors (TGCT)—the most common solid malignancy in men aged 15–35 years. The American Joint Committee on Cancer (AJCC) 8th edition (2018) created the subclassifications pT1a (tumor size 4 cm are considered features associated with a higher recurrence risk, but not formally used for staging. The authors propose further understanding the subclassification’s potential impact in clinical practice, by summarizing current evidence and reviewing clinical cases in their institutions. Methods All consecutive cases of seminoma stage I, pT1 treated in two institutions between January 2005 and December 2016 were included. Clinical data were retrieved, and variables were analyzed using SPSS. Relevant literature on the topic was reviewed. Results Seminoma pT1 was identified in 58 patients. By using newly AJCC criteria, 29 (50%) would have been staged as pT1a and 29 (50%) pT1b. Median age at diagnosis was similar (33 in pT1a vs 32 in pT1b). Median follow-up time 5.8 years. Almost half (45%) of pT1b patients had a tumor size

Background: Rete testis dysplasia is a cystic anomaly arising from the rete testis presenting normally in the pediatric population. These cases usually regress spontaneously without the need for surgical intervention. There are rare, reported cases of rete testis dysplasia in adulthood, which have been managed surgically., Case Presentation: A 58-year-old man presented with lower urinary tracts symptoms and found to have a slightly larger right testicle namely in the lower pole near the epididymis. Investigation was done using ultrasound of the testicles with Doppler showing an 8 mm cyst contained in 16.5×12.1 mm cystic dysplasia near the rete testis. MRI of the testicles revealed a small intratesticular cyst with adjacent band-like signals, in keeping with rete testis dysplasia. This patient was placed under surveillance and the rete testis dysplasia is stable after 6 months and will not be operated on unless progression on ultrasound is encountered., Clinical Discussion: The management of cystic dysplasia of the rete testis has been evolving with time. While there have never been clear-cut guidelines on the treatment of this condition, a radical orchiectomy of the affected testicle had traditionally been the preferred treatment option. There have only been three case reports of cystic dysplasia of the rete testis in adults, none of which are known to have been managed by observation., Conclusion: In conclusion, the authors report a unique case of rete testis dysplasia being managed conservatively showing the benign features of such a pathology, which may be actively surveyed through sequential imaging., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Signaling by androgens through androgen receptor (AR) is essential to complete spermatogenesis in the testis. Similarly, loss of the main estrogen receptor, estrogen receptor 1 (ESR1; also known as ERα), results in male infertility, due in part to indirect deleterious effects on the seminiferous epithelium and spermatogenesis. Effects of steroid hormones are induced primarily through genomic changes induced by hormone-mediated activation of their intracellular receptors and subsequent effects on nuclear gene transcription. However, androgens and estrogens also signal through rapid nonclassical pathways involving actions initiated at the cell membrane. Here we review the data that nonclassical androgen and estrogen signaling pathways support processes essential for male fertility in the testis and reproductive tract. The recent development of transgenic mice lacking nonclassical AR or ESR1 signaling but retaining genomic nuclear signaling has provided a powerful tool to elucidate the function of nonclassical signaling in the overall response to androgens and estrogens. Results from these mice have emphasized that nonclassical signaling is essential for full responses to these hormones, and absence of either nonclassical or classical AR or ESR1 pathways produces abnormalities in spermatogenesis and the male reproductive tract. Although additional work is required to fully understand how classical and nonclassical receptor signaling synergize to produce full steroid hormone responses, here we summarize the known physiological functions of the classical and nonclassical androgen and estrogen signaling pathways in the testis and reproductive tract. [ABSTRACT FROM AUTHOR]

The rete testis connects seminiferous tubules in which germ cells develop to the efferent ducts and the epididymis, where gametes mature and gain mobility. Several recent studies have thoroughly explored the morphogenesis of this structure in mice during embryonic and postnatal periods. A part of the rete testis has been shown to derive from the precursors of gonad somatic cells before sex determination. The other part forms from embryonal Sertoli cells of testis cords adjacent to the mesonephros. The transformation of Sertoli cells into rete testis cells is apparently not limited to the embryonic stage of development and continues during postnatal testis development. Recently, it was found that the rete testis participates in the formation and maintenance of specialized Sertoli cells in terminal segments of seminiferous tubules, transitional zones. Current views suggest that the transitional zones of the seminiferous tubules may represent a niche for spermatogonial stem cells, the site of the prolonged proliferation of Sertoli cells in the pubertal and postpubertal periods of testis development, and also could be a generator of spermatogenic waves. To sum up, the rete testis transports gametes from the testis to the epididymis, maintains pressure within seminiferous tubules, regulates the composition of the testicular fluid, and impacts the spermatogenic process itself. [ABSTRACT FROM AUTHOR]

An 18‐month‐old Angus bull presented to Auburn University College of Veterinary Medicine for a routine breeding soundness evaluation and lameness evaluation. He was classified as deferred potential breeder due to a lameness and was donated to the university. Following treatment, the bull's lameness resolved. He passed the breeding soundness examination in accordance with the Society for Theriogenology standards. However, avascular dilated areas at the level of the mediastinum testis of the right testicle were detected via Doppler ultrasonography. A high level of vascularity is routinely seen with neoplasia, such as teratomas. Due to the lack of vascularity, a presumptive diagnosis of tubular ectasia of the rete testis was made. The bull was castrated. The right testicle was submitted for histopathology revealing a definitive diagnosis of tubular ectasia of the rete testis. [ABSTRACT FROM AUTHOR]

Reproduction in males requires the transfer of spermatozoa from testis tubules via the rete system to the efferent ductules, epididymis, and vas deferens. The rete therefore forms an essential bridging system between the testis and excurrent ducts. Yet the embryonic origin and molecular regulation of rete testis development is poorly understood. This review examines the anatomy, endocrine control, and development of the mammalian rete testis, focusing on recent findings on its molecular regulation, identifying gaps in our knowledge, and identifying areas for future research. The rete testis develops in close association with Sertoli cells of the seminiferous cords, although unique molecular markers are sparce. Most recently, modern molecular approaches such as global RNA-seq have revealed the transcriptional signature of rete cell precursors, pointing to at least a partial common origin with Sertoli cells. In the mouse, genes involved in Sertoli cell development or maintenance, such as Sox9 , Wt1 , Sf1 , and Dmrt1 , are also expressed in cells of the rete system. Rete progenitor cells also express unique markers, such as Pax8, E-cadherin, and keratin 8. These must directly or indirectly regulate the physical joining of testis tubules to the efferent duct system and confer other physiological functions of the rete. The application of technologies such as single-cell RNA-seq will clarify the origin and developmental trajectory of this essential component of the male reproductive tract. [ABSTRACT FROM AUTHOR]

Cystic dysplasia of the rete testis (CDT) is a rare cause of scrotal swelling in children. It is a congenital disorder and it can be associated with other genitourinary abnormalities. At present, there is no clear consensus on treatment. Surgical approach has traditionally been the treatment of choice, while, more recently, conservative approach has been applied, justified by the benign nature of the lesion and after few cases of spontaneous regression have been documented. Ultrasonography, supported by negative tumor markers, plays a key role in the diagnostic work up and during observational follow-up. We report a further case of spontaneous regression of suspected CDT in an 18-month-old boy, who has been followed with clinic and ultrasonographic checks. [ABSTRACT FROM AUTHOR]

Spermatogonial stem cells originate from gonocytes and undergo self-renewal and differentiation to generate mature spermatozoa via spermatogenesis in the seminiferous tubules of the testis in male mammals. Owing to the unique capacity of these cells, the spermatogonial stem cell transplantation technique, which enables the restoration of male fertility by transfer of germlines between donor and recipient males, has been developed. Thus, spermatogonial stem cell transplantation can be used as an important next-generation reproductive and breeding tool in livestock production. However, in large animals, this approach is associated with many technical limitations and inefficiency. Furthermore, research regrading spermatogonial stem cell transplantation in stallions is limited. Therefore, this review article describes the history and current knowledge regarding spermatogonial stem cell transplantation in animals and challenges in establishing an experimental protocol for successful spermatogonial stem cell transplantation in stallions, which have been presented under the following heads: spermatogonial stem cell isolation, recipient preparation, and spermatogonial stem cell transplantation. Additionally, we suggest that further investigation based on previous unequivocal evidence regarding donor-derived spermatogenesis in large animals must be conducted. A detailed and better understanding of the physical and physiological aspects is required to discuss the current status of this technique field and develop future directions for the establishment of spermatogonial stem cell transplantation in stallions., Competing Interests: No potential conflict of interest relevant to this article was reported., (© Copyright 2024 Korean Society of Animal Science and Technology.)

A 60-year-old male reported a painless left scrotal mass for months. The testicle was removed due to the fact that malignancy could not be excluded from physical examination, tumor markers, or scrotal imaging. Afterward, further pathological examinations diagnosed the patient's condition as tubular ectasia of the rete testis (TERT) rather than malignancy. TERT is a rare benign lesion that may be mistaken for malignant tumors at first glance. However, distinguishing diagnoses can be made with a combination of sonography and magnetic resonance imaging without much difficulty. That is why it is highly recommended to consider this condition before confirming the final diagnosis of similar cases.

Background: Although the prognosis of childhood cancer survivors has increased dramatically during recent years, chemotherapy and radiation treatments for cancer and other conditions may lead to permanent infertility in prepubertal boys. Recent developments have shown that spermatogonial stem cell (SSC) transplantation may be a hope for restoring fertility in adult survivors of childhood cancers. For this reason, several centres around the world are collecting and cryopreserving testicular tissue or cells anticipating that, in the near future, some patients will return for SSC transplantation. This review summarizes the current knowledge and utility of SSC transplantation techniques.Objective and Rationale: The aim of this narrative review is to provide an overview of the currently used experimental injection techniques for SSC transplantation in animal and human testes. This is crucial in understanding and determining the role of the different techniques necessary for successful transplantation.Search Methods: A comprehensive review of peer-reviewed publications on this topic was performed using the PubMed and Google Scholar databases. The search was limited to English language work and studies between 1994 (from the first study on SSC transplantation) and April 2019. Key search terms included mouse, rat, boar, ram, dog, sheep, goat, cattle, monkey, human, cadaver, testes, SSC transplantation, injection and technique.Outcomes: This review provides an extensive clinical overview of the current research in the field of human SSC transplantation. Rete testis injection with ultrasonography guidance currently seems the most promising injection technique thus far; however, the ability to draw clear conclusions is limited due to long ischemia time of cadaver testis, the relatively decreased volume of the testis, the diminishing size of seminiferous tubules, a lack of intratesticular pressure and leakage into the interstitium during the injection on human cadaver testis. Current evidence does not support improved outcomes from multiple infusions through the rete testes. Overall, further optimization is required to increase the efficiency and safety of the infusion method.Wider Implications: Identifying a favourable injection method for SSC transplantation will provide insight into the mechanisms of successful assisted human reproduction. Future research could focus on reducing leakage and establishing the optimal infusion cell concentrations and pressure. [ABSTRACT FROM AUTHOR]

Six males ferret used in this present study, the age of animal (four-six) years. The head of epididymis located at the lateral aspect of the testicule, it consist of head, body and tail. The efferent ductules connected with head of epididymis, the epithelial lining of the efferent ductules and the epididymis head in the ferret were pseudo stratified ciliated columnar. Sterocilia similar to brush border projected from free surface of epithelial linings of efferent ductules and the epididymis head. The type of epithelial cells found in the mucosa of epididymis head includes, basal, principle, clear and apical cells, beside the intra epithelial cavities were distributed among the epithelial cells of the efferent ductules and epididymis head. The efferent ductules was surrounded by abundant of smooth muscle fibers arranged in circular arrangement. The rete testis of the ferret testicule was large and lined with simple cuboidal cells. [ABSTRACT FROM AUTHOR]

During human fetal development, sex differentiation occurs not only in the gonads but also in the adjacent developing reproductive tract. However, while the cellular composition of male and female human fetal gonads is well described, that of the adjacent developing reproductive tract remains poorly characterized. Here, we performed single-cell transcriptomics on male and female human fetal gonads together with the adjacent developing reproductive tract from first and second trimesters, highlighting the morphological and molecular changes during sex differentiation. We validated different cell populations of the developing reproductive tract and gonads and compared the molecular signatures between the first and second trimesters, as well as between sexes, to identify conserved and sex-specific features. Together, our study provides insights into human fetal sex-specific gonadogenesis and development of the reproductive tract beyond the gonads. [Display omitted] • Pronounced sex differences emerge in the reproductive tract in the first trimester • Key genes in the early reproductive tract associate with urogenital diseases • The human rete testis and rete ovarii share common features in the first trimester • Stromal and epithelial signatures diverge in gonads and adjacent reproductive tract Using single-cell transcriptomics and extensive validation by immunofluorescence, Taelman and Czukiewska et al. examine the development of fetal human gonads and the adjacent reproductive tract of both sexes during the first and second trimesters, identifying morphological and molecular changes as well as conserved and sex-specific features during differentiation. [ABSTRACT FROM AUTHOR]

Background: The mechanisms by which the rete testis joins the efferent ducts, which joins the Wolffian duct during development, are not known. Mouse and chick models have been helpful in identifying genes that are important for the development of each part, but genes have not been identified as to those that play a role in the joining of each part. Clinical implications of the failure of the male reproductive tract to form a fully functional conduit for spermatozoa are not trivial. Epididymal disjunction, the failure of the efferent ducts to join the testis, is one of several epididymal anomalies that have been observed in some boys who were cryptorchid at birth. Objective: A systematic review of studies focusing on the morphogenesis of the mesonephric duct and mesonephric tubules in different species, and identification of clinical issues should there be failure of these tissues to develop. Design: PubMed and GUDMAP databases, and review of books on kidney development were searched for studies reporting on the mechanisms of morphogenesis of the kidney and epididymis. Main outcomes measure(s): Gaps in our knowledge were identified, and hypotheses coupled with suggestions for future experiments were presented. Results: A total of 64 papers were identified as relevant, of which 53 were original research articles and 11 were book chapters and reviews covering morphogenesis and clinical issues. Investigators utilized multiple species including, human, mouse, chick, Xenopus, bovine, and sheep. Conclusion: Fundamental understanding of the morphogenesis of the male reproductive tract is limited, especially the morphogenesis of the rete testis and efferent ducts. Therefore, it is not surprising that we do not understand how each part unites to form a whole. Only one mechanism of joining of one part of the tract to another was identified: the joining of the Wolffian duct to the cloaca via controlled apoptosis. [ABSTRACT FROM AUTHOR]

Objectives Rete testis invasion by germ cell tumors is frequently concomitant with lymphovascular or spermatic cord invasion (LVI/SCI); independent implications for staging are uncertain. Methods In total, 171 seminomas and 178 nonseminomatous germ cell tumors (NSGCTs; 46 had 1%-60% seminoma component) came from five institutions. Metastatic status at presentation, as a proxy for severity, was available for all; relapse data were unavailable for 152. Rete direct invasion (ReteD) and rete pagetoid spread (ReteP) were assessed. Results ReteP and ReteD were more frequent in seminoma than NSGCT. In seminoma, tumor size bifurcated at 3 cm or more or less than 3 cm predicted metastatic status. Tumors with ReteP or ReteD did not differ in size from those without invasions but were less than with LVI/SCI; metastatic status or relapse did not show differences. In NSGCT, ReteP/ReteD did not correlate with size, metastatic status, or relapse. Conclusions Findings support retaining American Joint Committee for Cancer pathologic T1 stage designation for rete testis invasion and pT1a/pT1b substaging of seminoma. [ABSTRACT FROM AUTHOR]

Background: Tubular ectasia of the rete testis (TERT) is a dilatation of the seminiferous tubules of the mediastinum testis. It tends to be asymptomatic and usually constitutes an incidental finding of imaging studies. Scrotal ultrasound (SU) shows tubules with a cystic appearance, suggesting a number of possible diagnoses, including testicular tumours. Objective: To review our experience and describe the clinical and ultrasound features. Design: Retrospective descriptive review. Setting: The images were obtained by SU on an ambulatory basis. SU was performed with the Pro Focus Ultrasound System (BK Medical®, Massachusetts, USA). The indications of the exploration, the SU findings, and the associated conditions were the variables analysed. Participants: 460 SU studies performed in our hospital between 2010 and 2013. The subjects were men, with a median age of 66 years (range 47–78). Outcome Measurements and Statistical Analysis: SPSS® version 20 (IBM, New York, USA) was used for the descriptive analysis of the data. Results and Limitations: TERT was identified in 23 out of 460 SU studies performed. SU was indicated due to the presence of scrotal swelling in 7 patients (30%), an epididymal mass in 8 patients (35%), mild testicular pain in 6 patients (26%), and post-surgical control in 2 asymptomatic patients. Within the 23 patients, 10 (43.4%) were diagnosed with an epididymal cyst, 3 (13%) with chronic epididymitis, and 9 (39%) with a hydrocoele. With regard to associated conditions, 3 (13%) had undergone ipsilateral inguinal hernia repair, 3 (13%) had undergone ipsilateral hydrocoelectomy, and 1 (4%) had a history of contralateral testicular cancer. TERT was unilateral in all cases. No malignant degeneration of the lesions was observed in our series. Conclusions: According to our experience, TERT is an incidental condition where detailed clinical history, adequate physical examination, and SU findings can lead to the diagnosis. Knowledge of this disease is therefore essential for urologists. Patient summary: In this report we analyse the clinical features and the SU findings associated with TERT, a condition incidentally found in imaging studies of men in their 60s usually performed for other reasons.