Testis Mass Research Articles

A Case of Metastatic Testicular Cancer after Kidney Transplantation in which Complete Remission was Achieved

We report a case of testicular cancer after kidney transplantation in a 29-year-old man. Twenty-two years after the surgery, computed tomography (CT) showed a retroperitoneal mass 3 cm in diameter. Positron emission tomography (PET) -CT revealed high FDG uptake in both the right testis and retroperitoneal mass. Regarding serum tumor markers, α fetoprotein (AFP) was slightly elevated to 12.5 ng/ml. He underwent right radical orchiectomy, and pathological examination revealed pure seminoma. After surgery, the serum AFP level remained high (12. 9 ng/ml), and we initially considered this nonseminoma patient to have a good prognosis according to International Germ Cell Consensus Classification. During three cycles of a combination regimen including bleomycin, etoposide, and cisplatin (BEP), we performed adjustment of immunosuppressive therapy, treatment for Cytomegalovirus infection (valganciclovir hydrochloride), and that for other adverse events associated with systemic chemotherapy. The chemotherapy schedule was delayed, and bleomycin (third course, day 15) was skipped due to adverse effects. After 3 cycles of BEP, the retroperitoneal lymph node metastasis shrunk from 3.0 to 1.5 cm in diameter. In contrast to the good radiological response, the serum AFP level gradually increased during the treatment to 102.6 ng/ml. Therefore, we did not consider the AFP elevation to have derived from residual cancer, and decided to perform close follow-up. During the 3-year follow-up, AFP decreased to around 20 ng/ml, and PET-CT did not show any uptake in the retroperitoneal mass or other sites.

Exposure to novel females increases fecundity in adult male prairie voles.

Social circuitry of the mammalian brain can influence male reproductive physiology. This often manifests as plasticity in sperm production or allocation, particularly in response to male-male competition. However, socially mediated testicular plasticity has not been investigated with respect to mating and parental strategy. Testis mass and sperm production of sexually naïve and female-exposed adult male individuals of three rodent species were compared: the socially monogamous and paternal prairie vole (Microtus ochrogaster), the promiscuous and non-paternal meadow vole (Microtus pennsylvanicus), and the promiscuous and non-paternal house mouse (Mus musculus). Monogamously paired prairie vole males exhibited significantly larger testes and greater sperm production than naïve prairie vole males. Comparatively, there were no significant differences between naïve and monogamously paired male meadow voles or mice. To investigate the role of olfactory cues for regulating this phenomenon in prairie voles, a group of naïve males exposed to soiled bedding from novel females was used. These males were more similar to paired males than to naïve males not exposed to novel female odors, demonstrating a strong role of the social olfactory system. Further, while the predictions of sperm competition theory (species with greater female promiscuity have larger testes than closely related species with less female promiscuity) are consistent between naïve meadow voles and prairie voles, the prediction does not hold for monogamously paired prairie voles and meadow voles. This demonstrates the complexity of internal social dynamics and reproductive pressures which socially monogamous paternal males face and the evolutionary adaptions that may develop in response.

Fertility up in flames: Reduced fertility indices as a consequence of a simulated heatwave on small African mammals

AbstractWith the increasing frequency and intensity of heatwaves due to climate change, the survival and reproductive success of mammals could be under significant threat. However, the specific effects of these environmental stressors on mammalian reproductive fitness remain insufficiently explored. This study investigates the impact of a simulated heatwave on male fertility indices in two African rodent species: the mesic four‐striped field mouse (Rhabdomys dilectus) and the Namaqua rock mouse (Micaelamys namaquensis) during the breeding season. We measured key indicators of male fertility, including testes mass, testes volume, seminiferous tubule diameter, the presence of sperm, and plasma testosterone levels. Our findings reveal that both species experienced significant effects on male fertility indices, with the smaller R. dilectus showing a decline in all fertility indices following a simulated heatwave. These results suggest that the projected increase in heatwave events may compromise the reproductive success of small mammals, potentially leading to population declines. Finally, this study highlights the need for focused studies on the effect of heatwaves on long‐term reproductive success in both males and females.

Sperm competition intensity shapes divergence in both sperm morphology and reproductive genes across murine rodents.

It remains unclear how variation in the intensity of sperm competition shapes phenotypic and molecular evolution across clades. Mice and rats in the subfamily Murinae are a rapid radiation exhibiting incredible diversity in sperm morphology and production. We combined phenotypic and genomic data to perform phylogenetic comparisons of male reproductive traits and genes across 78 murine species. We identified several shifts towards smaller relative testes mass (RTM), presumably reflecting reduced sperm competition. Several sperm traits were associated with RTM, suggesting that mating system evolution selects for convergent suites of traits related to sperm competitive ability. We predicted that sperm competition would also drive more rapid molecular divergence in species with large testes. Contrary to this, we found that many spermatogenesis genes evolved more rapidly in species with smaller RTM due to relaxed purifying selection. While some reproductive genes evolved rapidly under recurrent positive selection, relaxed selection played a greater role in underlying rapid evolution in small testes species. Our work demonstrates that postcopulatory sexual selection can impose strong purifying selection shaping the evolution of male reproduction and that broad patterns of molecular evolution may help identify genes that contribute to male fertility.

Sperm competition intensity shapes divergence in both sperm morphology and reproductive genes across murine rodents.

It remains unclear how variation in the intensity of sperm competition shapes phenotypic and molecular evolution across clades. Mice and rats in the subfamily Murinae are a rapid radiation exhibiting incredible diversity in sperm morphology and production. We combined phenotypic and genomic data to perform phylogenetic comparisons of male reproductive traits and genes across 78 murine species. We identified several shifts towards smaller relative testes mass, presumably reflecting reduced sperm competition. Several sperm traits were associated with relative testes mass, suggesting that mating system evolution selects for convergent suites of traits related to sperm competitive ability. We predicted that sperm competition would also drive more rapid molecular divergence in species with large testes. Contrary to this, we found that many spermatogenesis genes evolved more rapidly in species with smaller relative testes mass due to relaxed purifying selection. While some reproductive genes evolved rapidly under recurrent positive selection, relaxed selection played a greater role in underlying rapid evolution in small testes species. Our work demonstrates that postcopulatory sexual selection can impose strong purifying selection shaping the evolution of male reproduction, and that broad patterns of molecular evolution may help identify genes that contribute to male fertility.

Nicotinamide mononucleotide ameliorates ionizing radiation-induced spermatogenic dysfunction in mice by modulating the glycolytic pathway.

Radiotherapy, a common cancer treatment, leads to infertility in male cancer survivors, particularly young and middle-aged patients. Nicotinamide mononucleotide (NMN), a precursor of nicotinamide adenine dinucleotide (NAD +), plays crucial roles in energy metabolism, DNA repair, and gene expression. The purpose of this study is to investigate the protective effects and underlying mechanisms of NMN against ionizing radiation (IR)-induced testicular injury and spermatogenic dysfunction in an adult male mouse model. To assess the effects of NMN, single whole-body γ-ray irradiation is used to induce testicular injury and spermatogenic dysfunction in adult male mice. NMN is orally administered at 500 mg/kg before and after IR exposure. The structural and cellular damage to the testes caused by 5 Gy γ-ray irradiation, as well as the protective effect of NMN on testicular spermatogenic dysfunction, are evaluated. The serum hormone testosterone, LH, and FSH levels, as well as testicular NAD +, lactate, and pyruvate levels, are detected. Furthermore, the expressions of the apoptosis-related genes Bcl-2, Bax, and Caspase-3 and the rate-limiting enzymes HK2, PKM2, and LDHA, which are potentially associated with the mechanism of injury, are examined. The results demonstrate that 5 Gy γ-ray irradiation exposure causes a decrease in the serum testosterone, LH, and FSH levels in adult male mice, as well as in the testicular NAD +, lactate, and pyruvate levels, and causes damage to the testicular structure and cells. Morphometric analysis reveal a decrease in the testis mass, seminiferous tubule diameter, and height of the germinal epithelium. The sperm quantity, motility, and testicular volume are reduced in the 5 Gy group but are restored by NMN supplementation. NMN intervention downregulates the expressions of proapoptotic genes ( Bax and Caspase-3) and upregulates the expression of an antiapoptotic gene ( Bcl- 2). Sertoli cells marker genes ( WT-1, GATA-4, SOX9, and vimentin) and glycolysis rate-limiting enzyme-encoding genes ( HK2, PKM2, LDHA) are significantly upregulated. In summary, NMN has a positive regulatory effect on testicular spermatogenic dysfunction in male mice induced by ionizing radiation. This positive effect is likely achieved by promoting the proliferation of spermatogenic cells and activating glycolytic pathways. These findings suggest that NMN supplementation may be a potential protective strategy to prevent reproductive damage to male subjects from ionizing radiation.

Horn size is linked to Sertoli cell efficiency and sperm size homogeneity during sexual development in common eland (Taurotragus oryx).

Background: In polygynous species, the development of secondary sexual characters is usually decisive for male reproductive success. However, our understanding about the links between the growth of these traits and reproductive efficiency is still elusive. Most research efforts in this topic have been also focused on adult males, although the development of some secondary sexual characters, like bovid horns, typically starts after birth, continues during the puberty and in some species, such as the common eland, slows or even stops during adulthood. In this study, we investigated the relationships between horn size and testicular function during sexual development in common elands using a comprehensive approach that considers both spermatogenic and sperm parameters. Methods: Twenty-two non-sexually mature common elands were used for the present study. Horn size, body mass, testes mass, and gonadosomatic index were assessed. Spermatogenic activity was determined by cytological and histological analyses. Sperm concentration, morphology, morphometry, and intramale variation in sperm size were evaluated on epididymal sperm samples. Cluster analysis was performed to explore the influence of age on relationships between horn size and reproductive function. Results: We found that bigger horns are associated with increased Sertoli cell efficiency and reduced intramale variation in sperm size. Both parameters were not related to one another while they have shown to be associated with enhanced sperm quality in ungulates. Moreover, horn size was positively linked to the testis mass, sperm concentration, and testicular investment in the seminiferous epithelium. Spiral length and basal circumference were the horn traits most strongly correlated with spermatogenic and sperm parameters as well as those responsible for the sexual dimorphism in this species. Cluster analysis rendered two groups: the first one including males ≤30months old, while the second one those >30months old. Horn development and reproductive function were still correlated within age groups, with the strongest relationship found between horn size and sperm size homogeneity in males >30months old. Conclusion: Taken together, our results indicate that horn size can be regarded as a good index of male reproductive potential during sexual development and provide insights into the role of secondary sexual characters in sexual selection dynamics.

Rare Case of Testicular Metastasis of Prostate Carcinoma after 13 Years of Prostatectomy: A Case Report and Review of the Literature

Metastasis of prostate cancer to the testes is a rare phenomenon, often indicating advanced-stage disease. This case report details a 79-year-old man with a history of prostate cancer, who underwent endoscopic-extraperitoneal radical prostatectomy and bilateral pelvic lymph node dissection. The patient subsequently received radiation therapy for local recurrences. Thirteen years post-surgery, a testicular ultrasound revealed a cystic mass in the left testis, initially suspected to be a primary neoplasm. However, pathology with immunohistochemical analyses confirmed metastasis from prostate adenocarcinoma. Testicular metastasis of prostate cancer is uncommon, underscoring the aggressiveness and potential spread of the tumor. Clinically evident testicular metastases develop in only a small percentage of prostate cancer patients. This case report highlights the importance of considering metastatic disease in the differential diagnosis of testicular masses and the necessity of clinicopathologic correlation in such evaluations. Early detection and accurate diagnosis are crucial for managing testicular metastasis and improving patient outcomes. The case also emphasizes the significance of long-term follow-up in prostate cancer patients, as metastasis can occur many years post-initial treatment. Furthermore, it illustrates the critical role of advanced imaging techniques and thorough pathological assessments in identifying and managing metastatic spread. This report contributes to the limited but growing body of literature on testicular metastasis from prostate cancer, providing insights for clinicians in recognizing and managing this rare but serious complication. It underscores the need for ongoing research to better understand the mechanisms of metastatic spread and develop targeted therapeutic strategies.

The origins and drivers of sexual size dimorphism in sharks.

While sexual size dimorphism (SSD) is abundant in nature, there is huge variation in both the intensity and direction of SSD. SSD results from a combination of sexual selection for large male size, fecundity selection for large female size and ecological selection for either. In most vertebrates, it is variation in the intensity of male-male competition that primarily underlies variation in SSD. In this study, we test four hypotheses regarding the adaptive value of SSD in sharks-considering the potential for each of fecundity, sexual, ecological selection and reproductive mode as the primary driver of variation in SSD between species. We also estimate past macroevolutionary shifts in SSD direction/intensity through shark phylogeny. We were unable to find evidence of significant SSD in early sharks and hypothesise that SSD is a derived state in this clade, that has evolved independently of SSD observed in other vertebrates. Moreover, there is no significant relationship between SSD and fecundity, testes mass or oceanic depth in sharks. However, there is evidence to support previous speculation that reproductive mode is an important determinant of interspecific variation in SSD in sharks. This is significant as in most vertebrates sexual selection is thought to be the primary driver of SSD trends, with evidence for the role of fecundity selection in other clades being inconsistent at best. While the phylogenetic distribution of SSD among sharks is superficially similar to that observed in other vertebrate clades, the relative importance of selective pressures underlying its evolution appears to differ.

Ex-vivo microscopic oncotesticular sperm extraction: step-by-step surgical technique at time of radical orchiectomy

To demonstrate the intraoperative surgical techniques required for simultaneous radical orchiectomy and microscopic oncotesticular sperm extraction (m-OncoTESE) in a step-by-step fashion. Video presentation. University Hospital (University of Chicago). A 37-year-old man (status after right orchiectomy at another institution for stage II-C testicular seminoma with positive preoperative tumor markers) was referred for contralateral orchiectomy of multifocal left testis mass and fertility preservation. Semen analysis before, microscopic testicular sperm extraction during, and semen or testicular specimen analysis after the first orchiectomy were unable to identify any sperm. A postoperative analysis of the m-OncoTESE performed on the left testis resulted in the cryopreservation of 200,000 motile sperm for future assisted reproductive technology (i.e., invitro fertilization or invitro fertilization-intracytoplasmic sperm injection). Left radical orchiectomy and left m-OncoTESE. A comprehensive visual documentation of m-OncoTESE surgical techniques with concurrent commentary detailing the reasons behind each surgical step. A brief discussion on the background of m-OncoTESE and alternative fertility preservation methods accompanies the procedure. This video provides a step-by-step guide to performing an m-OncoTESE (proceeding a radical orchiectomy in a patient with testicular cancer) as a means of fertility preservation in an azoospermic patient. Successful extraction and cryopreservation of testicular spermatozoa were achieved after targeted ex-vivo testicular microdissection. Sperm extraction via m-OncoTESE is a viable option for azoospermic patients with testicular cancer undergoing radical orchiectomies. The use of preoperative imaging and microsurgical techniques facilitates and optimizes surgical dissection and sperm recovery.

Seasonal remodeling of visceral organs in the invasive desert gecko Tarentola annularis.

In winter, many reptiles have a period of inactivity ("brumation"). During brumation there is no energetic intake, therefore there would be an advantage to reducing energetic expenditure. The size of energetically costly organs, a major determinant of metabolic rate, is known to be flexible in many tetrapods. Seasonal plasticity of organ size could serve as both an energy-saving mechanism and a source of nutrients for brumating reptiles. We studied a population of an invasive gecko, Tarentola annularis, to test for seasonal changes in activity, metabolic rate, and mass of various organs. The observed period of inactivity was December-February. Standard metabolic rates during the activity season were 1.85 times higher than in brumating individuals. This may be attributed to decreased organ mass during winter: heart mass decreased by 37%, stomach mass by 25%, and liver mass by 69%. Interestingly, testes mass increased by 100% during winter, likely in preparation for the breeding season, suggesting that males prioritize breeding over other functions upon return to activity. The size of the kidneys and lungs remained constant. Organ atrophy occurred only after geckos reduced their activity, so we hypothesize that organ mass changes in response to (rather than in anticipation of) cold winter temperatures and the associated fasting. Degradation of visceral organs can maintain energy demands in times of low supply, and catabolism of the protein from these organs can serve as a source of both energy and water during brumation. These findings bring us closer to a mechanistic understanding of reptiles' physiological adaptations to environmental changes.

Influence of triazines and lipopolysaccharide coexposure on inflammatory response and histopathological changes in the testis and liver of BalB/c mice

BackgroundTriazines are environmental active chemicals that have been reported to alter the inflammatory status of the gonads. We tested the anti-inflammatory effect of the triazines (atrazine; ATZ, simazine; SMZ and cyanazine; CYZ) on the testis and compared it with the more classical liver model that has substantial populations of resident macrophages comparable to the testis. MethodsBalB/c mice were treated with 25 mg/kg ATZ, SMZ and CYZ for 30 days and injected with lipopolysaccharide (0.5 mg/kg i.p.) 6 h before sacrifice. Myeloperoxidase activity and nitric oxide level in the testis and liver homogenates were determined by spectrophotometry whereas tumor necrosis factor-alpha and interleukin-6 concentrations were evaluated by immunoassay. Haematoxylin and eosin stained sections of the tissues were observed using a light microscope. ResultsMyeloperoxidase activity, nitric oxide, tumor necrosis factor-alpha, and interleukin-6 levels were decreased in the liver and testis of the triazines co-treated animals. SMZ has the most potent inhibitory effect and ATZ the least effect on inflammatory mediators in both tissues. Microscopic evaluation showed loss of inflammatory cells in the inter-tubular areas of the testis and few patchy masses of infiltrating inflammatory cells around the central vein of the liver. ConclusionTriazines inhibit the levels of inflammatory mediators in the testis and liver of mice. The anti-inflammatory effect of triazines in a lipopolysaccharide-induced inflammation model was established in this study.

Effects of sub-chronic exposure to microcystin-LR on the endocrine system of male rats

Microcystins (MCs) can cause reproductive and developmental toxicity and disrupt endocrine homeostasis in mammals. In the present study, male, Sprague-Dawley (SD) rats were administrated 3 or 30 μg MC-LR/kg, body mass (bm) per day via intraperitoneal (i.p.) injections for 6 weeks. Effects of MC-LR on histology, hormone concentrations, gene transcriptional profiles and protein expressions along the hypothalamic-pituitary-adrenal (HPA), ‐gonad (HPG) and -thyroid (HPT) axes were assessed. Sub-chronic administration with MC-LR caused histological damage to hypothalamus, pituitary, adrenal, testes and thyroid and affected relative masses of pituitary, adrenal and testes. The HPA axis was activated and serum concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were significantly augmented. Along the HPG axis, serum concentrations of gonadotropin-releasing hormone (GnRH) and dihydrotestosterone (DHT) were diminished, while concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) and estradiol (E2) were augmented. For the HPT axis, only concentrations of free tetra-iodothyronine (fT4) were significantly diminished, while concentrations of thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH) or free tri-iodothyronine (fT3) were not significantly changed. Also, several genes and proteins related to synthesis of steroid hormones were significantly altered. Findings of the present study illustrate that MC-LR can cause endocrine-disrupting effects through the disruption of synthesis and secretion of hormones along the HPA, HPG and HPT axes and negative feedback regulation. Also, there could be crosstalk among HPA, HPG and HPT axes. These findings elucidate mechanisms of endocrine-disrupting effects of MCs.

Small Testicular Masses: Contemporary Diagnostic and Treatment Strategies, Future Directions, and Knowledge Gaps

The incidental discovery of small masses in the testicles of young men is becoming an increasing clinical dilemma. We are learning that the malignancy rate in masses ≤ 2 cm is much lower than traditionally thought and could be as low as 13% to 21%. The challenge remains in identifying which of these patients harbor malignant tumors that need to be treated, and benign lesions that could be safely surveilled. The aim of this narrative review is to discuss the current scientific evidence, diagnostic work-up, and treatment strategies for small testicular masses. We also discuss selection criteria, follow-up schedules and triggers for intervention for the surveillance of these small testis masses. Furthermore, we give a set of recommendations for assessing and treating these patients, based on the available literature and our experience at a dedicated testicular cancer clinic.

Polychlorinated Biphenyls (PCBs) Impact Prostatic Collagen Density and Bladder Volume in Young Adult Mice Exposed during in Utero and Lactational Development.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants linked to deleterious health outcomes, including voiding dysfunction in developmentally exposed mice. Changes in prostate volume and/or extracellular matrix composition are associated with voiding dysfunction in men and animal models. Whether PCB-induced changes in voiding function in male mice occur in part via alterations to the prostate or an alternate mechanism is unclear. Therefore, we tested whether developmental exposure to the MARBLES PCB mixture altered prostate morphology in young adult offspring. C57Bl/6J female mice were dosed daily with the MARBLES PCB mixture at 0, 0.1, 1 or 6 mg/kg/d for two weeks prior to mating and through gestation and lactation, offspring were collected at 6 weeks of age. Ventral prostate mass was decreased in the 1 mg/kg/d PCB group compared to other PCB groups. There were no PCB-induced changes in prostate smooth muscle thickness, apoptosis, proliferation, or testes mass. PCBs impacted the prostate extracellular matrix; anterior prostate collagen density was decreased in the 1 mg/kg/d PCB group compared to all other groups. Normalized bladder volume was increased in male and female offspring in the 6 mg/kg/d PCB group compared to control. No change in water consumption, bladder mass or bladder smooth muscle thickness accompanied changes in bladder volume. Urine and serum creatinine concentrations were elevated but only in male mice. Together, these results suggest that developmental exposure to PCBs can influence prostate wet weight and prostate/bladder morphology, but PCBs do not promote prostate enlargement. Whether these changes persist throughout adult life and how they contribute to voiding function in animal models and humans is of future interest.

Long-term effects of incubation temperature on growth and thermal physiology in a small ectotherm.

Thermal conditions in the developmental environment can substantially affect an individual's phenotype, particularly in egg-laying ectotherms. However, whether these effects persist into adulthood is rarely examined. To investigate this, we incubated delicate skink, Lampropholis delicata, eggs at either cool (22°C), mild (26°C) or hot (30°C) temperatures. After hatching, we measured growth, thermal performance curves of locomotor activity, and thermal sensitivity of resting metabolic rate of offspring as juveniles (4-6 weeks of age), sub-adults (approx. 200 days of age), and adults (approx. 2 years of age), and then measured developmental temperature impacts on male fertility. Incubation temperature had a lasting effect on growth and locomotor performance, with cool and hot incubation temperatures resulting in faster growth and larger maximum size, and hot incubation temperatures reducing locomotor performance at all timepoints. Effects on resting metabolic rate were only present in sub-adults, with a higher metabolic rate at high and average body mass and negative metabolic scaling exponent in cool-incubated lizards. Additionally, cool and hot incubation treatments resulted in shorter sperm midpieces and heads. Incubation temperature did not affect testis mass or sperm count. Overall, our results demonstrate that incubation temperature can have lasting effects on later life stages, highlighting the importance of maternal nest-site selection, but that some effects are age dependent. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.

Dasatinib and quercetin increase testosterone andsperm concentration in mice.

Cellular senescence is a defense mechanism to arrest proliferation of damaged cells. The number of senescentcells increases with age in different tissues and contributes to the development of age-related diseases. Old mice treated with senolytics drugs, dasatinib and quercetin (D+Q), have reduced senescent cells burden. The aim of this study was to evaluate the effects of D+Q on testicular function and fertility of male mice. Mice (n = 9/group) received D (5 mg kg-1) and Q (50 mg kg-1) via gavage every moth for three consecutive days from 3 to 8 months of age. At 8 months mice were breed with young non-treated females and euthanized. The treatment of male mice with D+Q increased serum testosterone levels and sperm concentration and decreased abnormal sperm morphology. Sperm motility, seminiferous tubule morphometry, testicular gene expression and fertility were not affected by treatment. There was no effect of D+Q treatment in β-galactosidase activity and in lipofuscin staining in testes. D+Q treatment also did not affect body mass gain and testes mass. In conclusion, D+Q treatment increased serum testosterone levels and sperm concentration and decreased abnormal sperm morphology, however did not affect fertility. Further studies with older mice and different senolytics are necessary to elucidate the effects in the decline of sperm output (quality and quantity) associated with aging.

Sexual maturation in male bowhead whales (Balaena mysticetus) of the Bering-Chukchi-Beaufort Seas stock

Since the mid-1970s, study has focused on reproductive biology of female bowhead whales, while little has been described for males. This study evaluates testicular morphology (mass and length) and histology in relation to body length to determine the onset of male sexual maturity. Mean testis mass and mean testis length were highly correlated. Body length and mean testis mass were significantly correlated and an inflection of increased testicular mass occurred at approximately 12.5-13.0m suggesting the onset of puberty, and also indicated by histologic findings. Biological variability and the fact that few male animals have been examined within this critical length cohort do not allow determination of the onset of maturity with higher precision. Too few mature males have been landed in spring to make statistical comparisons of testes mass with autumn-landed animals within specific size cohorts. Two large (15.7m and 17.7m) males landed in spring had relatively small inactive testes and were diagnosed as pseudohermaphrodites; body length and mean testis length and seminiferous tubule diameter (STD) were not correlated with the other ‘normal’ whales. The smallest male confirmed as mature based on the presence of spermatocytes was 12.7m. The largest testes measured (combined mass 203kg) were from a whale landed in autumn. Mean STD for individual whales ranged from 33.3-170.9m and increased with mean testis weight and whale length. The STD is similar within a testis regardless of region evaluated, with minor variability. Some variation was noted for transverse sections within a cross section for some whales but no pattern was evident.

Pre- and postcopulatory competition affect testes mass and organization differently in two monophyletic mole-rat species, Georychus capensis and Fukomys damarensis.

Sperm competition results from postcopulatory continuation of male-male competition for paternity. The level of sperm competition is predicted to be highest in species with greater polyandry and weakest in monogamous pairs. Sperm competition levels can be indexed using traits that reflect male investment in fertilization, particularly relative testes mass (RTM). However, the relationship between RTM and levels of sperm competition may also be influenced by precopulatory competition selecting for higher levels of testosterone, also produced by the testes. To test the relationship between RTM and both pre- and postcopulatory male-male competition we compared two bathyergid mole-rat species, the promiscuous Georychus capensis and the monogamous eusocial Fukomys damarensis. The promiscuous species had not only larger RTM, but also a greater proportion of spermatogenic tissue, maximizing germ cell production as well. Conversely, the eusocial species had smaller testes, but a higher proportion of interstitial tissue (which contains the androgenic Leydig cells) and higher levels of testosterone. Consequently, testicular traits as well as testes mass may be under selection, but these are not normally measured. More research is required on relative investment in different testicular traits in relation to both pre- and postcopulatory selection pressures.

A Boy with 46,XX Karyotype (SRY double-positive) having a Leydig Cell Tumor.

Leydig cell tumors are the most common type of testicular sex cord stromal tumors. Presence of Y chromosome is associated with tumor risk in sex development disorder (DSD), however tumor development without Y chromosome are extremely rare. A 16-year-old boy diagnosed with Leydig cell tumor due to a mass in the right testis was referred after the right orchiectomy. In physical examination, left testis was 10 ml, and a labium residue in penoscrotal region with bilateral gynecomastia was present. Karyotype was 46,XX, and SRY was double-positive in FISH analysis. Ifosfamide, carboplatin and etoposide chemotherapy was initiated due to Leydig cell tumor. Here, we report the first pediatric case having 46,XX, SRY double-positive testicular DSD with Leydig cell tumor.