Computed Tomography Assessment of Retained Testes in Dogs

Cryptorchidism consists in the failure of one or both testicles to fully descend into the scrotum. The position of the retained testes can be abdominal or inguinal and may occur unilaterally or bilaterally. This retrospective, multi-center study aimed to describe the computed tomography (CT) features of retained testes in dogs. Nineteen CT scans of dogs, with either unilateral or bilateral cryptorchidism, were analyzed with both pre- and post-contrast imaging. The location, size, shape, margins, homogeneous parenchyma, and density calculated were examined with the Hounsfield unit. Statistical analyses were performed to assess the differences between the scrotal (ST) and undescended testes (UT) and to detect any correlation between the features, ages, and size of the dog. CT identified the retained testes and provided enhanced three-dimensional visualization compared to traditional ultrasound. This study revealed that the UT were significantly smaller than ST, with UT measuring around 70% of ST size. Additionally, the UT exhibited increased density in both pre- and post-contrast scans, potentially due to the reduced or absent spermatogenesis or to histological changes occurring in the parenchyma. While CT showed clear advantages, such as three-dimensional spatial resolution and deeper tissue penetration, limitations such as general anesthesia and radiation exposure should also be considered. However, the present study showed that CT could serve as a valuable second step tool in cases where ultrasound fails, particularly in challenging anatomical situations.

Shear Wave Elastography Evaluation of Testicular Stiffness in Dogs Affected by Testicular Pathology

Shear wave elastography (SWE) is an advanced ultrasound technique that assesses tissue stiffness by measuring shear wave speed (SWS) produced after an acoustic impulse. It includes bidimensional (2D-SWE) and focal point (pSWE) methods, allowing qualitative and quantitative analysis of tissue stiffness. This study aimed to describe the elastographic features of testicular abnormalities in dogs, supported by histological findings. Eighteen dogs with testicular abnormalities underwent B-mode ultrasound, power and color Doppler ultrasound, 2D-SWE, and pSWE before orchiectomy. Five cryptorchid testes were excluded and thirty-one testes (12 normal, 7 with leydigomas, 6 with seminomas, 1 with a round cell tumor, and 5 with orchitis) were examined. Normal testes, lesions, and adjacent healthy tissues (no evident ultrasound changes, NEUC) were sampled. Testicular abnormalities presented SWS values of 1.05-4.89 m/s (2D-SWE) and 1.35-5.31 m/s (pSWE). Significant differences were observed among normal testes, NEUC areas, and those with orchitis, leydigomas, and seminomas by both 2D-SWE and pSWE. Normal testes were significantly softer than ones with leydigomas, seminomas, and orchitis, and NEUC areas also had different SWS values compared to those with tumors and orchitis (p < 0.05). However, SWE techniques lacked specificity in differentiating between orchitis and tumors. Diagnostic accuracy of SWE techniques for testicular lesions remains challenging and requires further investigation to fully address its clinical potential.

Transferrin Receptor 2 in Canine Testicular Tumors: An Emerging Key Role in Seminomas

Transferrin Receptor 2 (TfR2) is a homolog of Transferrin Receptor 1 (TfR1), involved in regulating intra and extracellular iron levels. Altered iron pathways have been associated with cancer onset and progression; however, their role in canine tumors remains poorly explored. This study investigated TfR2 immunohistochemical expression in non-neoplastic canine testis for the first time and in the most common types of canine testicular tumors: intratubular seminomas (ITSEMs), diffuse seminomas (DSEMs), Leydig cell tumors (LCTs), and Sertoli cell tumors (SCTs). Immunohistochemical analysis revealed a differential pattern of TfR2 expression according to tumor type, with high expression observed in ITSEMs and DSEMs, occasional expression in LCTs, and absence in SCTs. These results suggest that TfR2 may play a relevant role in canine seminoma development. Furthermore, the specific expression of TfR2 in seminomas highlights its potential as a therapeutic target, where its role in iron regulation and possible compensatory mechanisms warrant further investigation.

Cryptorchidism and testicular cancer in the dog: unresolved questions and challenges in translating insights from human studies†

Cryptorchidism, the failure of one or both testes to descend into the scrotum, and testicular cancer show a strong correlation in both dogs and humans. Yet, long-standing medical debates persist about whether the location of undescended testes directly causes testicular cancer in humans or if both conditions stem from a common origin. Although testicular cancer is a prevalent disease in dogs, even less is known about its cause and correlation with testicular descent in this species. This review investigates the relation between these two disorders in dogs, drawing insights from human studies, and examines key biomarkers identified thus far. In addition, it explores potential causal links, including the impact of temperature on maturing testicular cells and a potential shared genetic origin. Notably, this literature review reveals significant differences between men and dogs in reproductive development, histological and molecular features of testicular tumors, and the prevalence of specific tumor types, such as Sertoli cell tumors in cryptorchid dogs and germ cell tumors in humans. These disparities caution against using dogs as models for human testicular cancer research and underscore the limitations when drawing comparisons between species. The paper concludes by suggesting specific research initiatives to enhance our understanding of the complex interplay between cryptorchidism and testicular cancer in dogs.

A massive alteration of gene expression in undescended testicles of dogs and the association of KAT6A variants with cryptorchidism

Cryptorchidism is the most common form of disorder of sex development in male dogs, but its hereditary predisposition is poorly elucidated. The gonadal transcriptome of nine unilaterally cryptorchid dogs and seven control dogs was analyzed using RNA-seq. Comparison between the scrotal and inguinal gonads of unilateral cryptorchid dogs revealed 8,028 differentially expressed genes (DEGs) (3,377 up-regulated and 4,651 down-regulated). A similar number of DEGs (7,619) was found by comparing the undescended testicles with the descended testicles of the control dogs. The methylation status of the selected DEGs was also analyzed, with three out of nine studied DEGs showing altered patterns. Bioinformatic analysis of the cDNA sequences revealed 20,366 SNP variants, six of which showed significant differences in allelic counts between cryptorchid and control dogs. Validation studies in larger cohorts of cryptorchid (n = 122) and control (n = 173) dogs showed that the TT genotype (rs850666472, p.Ala1230Val) and the AA genotype in 3'UTR (16:23716202G>A) in KATA6, responsible for acetylation of lysine 9 in histone H3, are associated with cryptorchidism (P = 0.0383). Both the transcript level of KAT6A and H3K9 acetylation were lower in undescended testes, and additionally, the acetylation depended on the genotypes in exon 17 and the 3'UTR. Our study showed that the massive alteration of the transcriptome in undescended testicles is not caused by germinal DNA variants in DEG regulatory sequences but is partly associated with an aberrant DNA methylation and H3K9 acetylation patterns. Moreover, variants of KAT6A can be considered markers associated with the risk of this disorder.

G Protein-Coupled Estrogen Receptor (GPER) and ERs Are Modulated in the Testis-Epididymal Complex in the Normal and Cryptorchid Dog

There is growing evidence by the literature that the unbalance between androgens and estrogens is a relevant condition associated with a common canine reproductive disorder known as cryptorchidism. The role of estrogens in regulating testicular cell function and reproductive events is supposedly due to the wide expression of two nuclear estrogen receptors (ERs), ER-alpha and ER-beta and a trans-membrane G protein-coupled estrogen receptor (GPER) in the testis. In this study, immunohistochemistry, Western blotting and qRT-PCR were used to assess the distribution and expression of GPER in the testis-epididymal complex in the normal and cryptorchid dog. ER-alpha and ER-beta were also evaluated to better characterize the relative abundances of all three receptors. In addition, in these tissues, the expression level of two proteins as SOD1 and Nrf2 normally associated with oxidative stress was investigated to evaluate a possible relationship with ERs. Our data revealed changes in the distribution and expression of the GPER between the normal and cryptorchid dog. In particular, dogs affected by cryptorchidism showed an upregulation of GPER at level of the examined reproductive tract. Also considering the obtained result of a modulation of SOD1 and Nrf2 expression, we could hypothesize the involvement of GPER in the cryptorchid condition. Further studies are, however, necessary to characterize the role of GPER and its specific signaling mechanisms.

Ultrasound-Based Technologies for the Evaluation of Testicles in the Dog: Keystones and Breakthroughs

Ultrasonography is a valuable diagnostic tool extensively used in the andrology of human and domestic animals, including dogs. This review aims to provide an overview of various technologies based on ultrasound, from the basic B-Mode ultrasonography to the more recent advancements, such as contrast-enhanced ultrasonography (CEUS) and ultrasound elastography (UEl), all of which are utilized in the evaluation of canine testicles. The review outlines the principles behind each of these technologies and discusses their application in assessing normal and abnormal testicular conditions. B-mode canine testicular ultrasonography primarily focuses on detecting focal lesions but has limitations in terms of objectivity. Other technologies, including Doppler ultrasonography, B-Flow, and CEUS, allow for the characterization of vascular patterns, which could be further measured using specific applications like spectral Doppler or quantitative CEUS. Additionally, ultrasound elastography enables the assessment of parenchyma stiffness both qualitatively and quantitatively. These ultrasound-based technologies play a crucial role in andrology by providing valuable information for evaluating testicular function and integrity, aiding in the identification of pathological conditions that may impact the health and quality of life of male dogs.

MicroRNA as epigenetic regulators of canine cryptorchidism

Cryptorchidism, the failed descent of one or both testes into the scrotum, is a common developmental disorder in male dogs. Cryptorchidism may affect canine fertility, reducing the quality of the semen, and may promote spermatic cord torsion and onset of neoplasia. MicroRNAs (miRNAs) are epigenetic regulators of gene expression and their dysregulation is associated with disorders of spermatogenesis and testis neoplasia. The present study aimed at investigating the expression of miRNAs in formalin-fixed, paraffin-embedded (FFPE) canine retained testes and testes affected by seminoma, and at integrating miRNAs to their target genes. Forty testicular FFPE specimens from 30 dogs were included - 10 scrotal and 10 contralateral retained from 10 unilateral cryptorchid dogs; 10 tumoral testes affected by seminoma from non-cryptorchid dogs; 10 scrotal normal testes from non-cryptorchid dogs included as the control. The expression level of three miRNAs, namely miR-302c-3p, miR-302a-3p, and miR-371-3p, associated with testicular disorders, were quantified using RT-qPCR. The comparative analysis demonstrated that the level of miR-302a-3p and miR-371a-3p were quantifiable exclusively in control testes. The expression level of miR-302c-3p was higher in the control than in the other groups; its expression decreased in retained testes compared to scrotal testes and testes with seminoma. Gene Ontology analysis pointed out that these miRNAs may be involved in the modulation of estrogen and thyroid hormone signaling pathways. In conclusion, this study demonstrated that miRNAs are dysregulated in canine cryptorchid and seminoma-affected testes compared to control tissues, confirming the pivotal role of miRNAs in cryptorchidism.

[Diagnostic utility of the anti-Mullerian hormone in companion animals]

The anti-Mullerian hormone is a glycoprotein secreted by Sertoli cells in males and granulosa cells in females. The initial identification of this hormone in canine and feline serum was achieved in 2011. Meanwhile, a variety of studies have demonstrated its clinical significance as a tool in the endocrine diagnosis. This review summarizes the current knowledge about anti-Mullerian hormone in small animal reproduction and describes future opportunities for its diagnostic usage.

Metastatic Sertoli cell tumour in a captive giant anteater (Myrmecophaga tridactyla)

There are a few studies on diseases of anteaters, but reports on reproductive lesions and neoplasms of these animals are scarce. This is the first report of a case of metastatic Sertoli cell tumour in a giant anteater (Myrmecophaga tridactyla). The animal had renal lesions associated with impaired renal function as indicated by serum biochemistry. Histopathological and immunohistochemical examinations provided a conclusive diagnosis of Sertoli cell tumour with metastasis to the liver, kidneys and lymph nodes.

Vasectomy and ovary-sparing spay in dogs: comparison of health and behavior outcomes with gonadectomized and sexually intact dogs

OBJECTIVE

To compare health and behavior outcomes for dogs that underwent vasectomy or ovary-sparing spay (hysterectomy) with sexually intact dogs or dogs that had undergone traditional castration or spay.

SAMPLE

6,018 dog owners responded to a web-based survey between November 3, 2021, and January 7, 2022.

PROCEDURES

Participants were asked demographic questions and to provide information about 1 or more dogs (living or deceased). Options for reproductive status were as follows: sexually intact, castrated, spayed (ovariohysterectomy or ovariectomy), vasectomy, or ovary-sparing spay (hysterectomy). Participants were asked questions about orthopedic and other health problems, cancer, and problematic behavior. Logistic regression models, survival analyses, and descriptive statistics were used to assess relationships between reproductive status and outcomes.

RESULTS

Owners provided valid surveys for 6,018 dogs, including 1,056 sexually intact, 1,672 castrated, and 58 vasectomized male dogs and 792 sexually intact, 2,281 spayed, and 159 female dogs that had undergone ovary-sparing spay. Longer exposure to gonadal hormones, regardless of reproductive status, was associated with reduced odds of general health problems and both problematic and nuisance behaviors.

CLINICAL RELEVANCE

To our knowledge, this study provides the first data on health and behavior outcomes of vasectomy and ovary-sparing spay in dogs and is the first to compare these outcomes to sexually intact and gonadectomized dogs. It adds to accumulating data on the mixed benefits and risks of removing the gonads to prevent reproduction and emphasizes the importance of developing an informed, case-by-case assessment of each patient, taking into consideration the potential risks and benefits of spaying or neutering and alternative reproductive surgeries.

Morphological characteristics of testicular interstitial cell tumors in dogs

The study presents an assessment of variability of histological structure, measurement, and comparison of size of the neoplasm obtained by ultrasonographic examination and pathological examination, as well as the morphometric dimensions of nuclei and cytoplasm of testicular interstitial cell tumors in dogs. The study involved 35 dogs with neoplasms of 46 testes, where 11 animals had interstitial cell tumors in both testes. Insignificant differences of the size of these neoplasms were revealed (p 0.05) using ultrasonography and pathoanatomical measurement methods. Hence, it allows using both methods to assess the size of interstitial cell tumors. In the study, interstitial cell tumor was detected in both testes at once in 50 % of cases in dogs, however, this might be due to specific characteristics of the sample, and further research is required. In the course of scientific work, a morphological study showed the presence of variability in histological structure of interstitial cell tumors, which can lead to incorrect interpretation of the morphological picture and misdiagnosis, e. g. adipocyte-like morphology of interstitial cell tumors have morphological similarity to a benign neoplasm from adipose tissue - lipoma. In addition, there was an extremely pronounced difference in size of cytoplasm (from 23.6 to 148.4 m; average 66.21 22.42 m) and nuclei (from 9 to 57.6 m; average 23.19 7.10 m) in tumor cells. It proves the presence of pronounced anisocytosis and anisokariosis, which should indicate malignancy of the neoplasm, however, testicular interstitial cell tumors extremely rarely metastasize in practice and according to numerous studies.

Vet-OncoNet: Malignancy Analysis of Neoplasms in Dogs and Cats

Simple Summary

An overview analysis of tumors in dogs and cats, dividing them into malignant and benign, may provide previously unknown information about the biological behavior of tumors in these species and may serve many veterinarians as a support for clinical decision making. Based on a sample of 16,272 cancer records, including 3266 cats and 13,006 dogs, the analysis found that cats have a fourfold risk of malignant tumors, as in some topographies. Sex appears to play a role in the malignancy only in dogs. Some dog breeds (Pit bull and Boxer) have a higher risk of malignant tumors as opposed to Shih tzu and Yorkshire terrier. District of residence was not relevant in predicting malignancy risk. Most importantly, the risk of malignant tumors increases by 20% every three years.

Abstract

Analysis of canine and feline tumor malignancy data can help clinicians identify high-risk patients and make more accurate decisions. Based on a sample of 16,272 cancer records, including 3266 cats and 13,006 dogs, collected from January 2019 to December 2021 in the Vet-OncoNet Network database, this study aimed to compare the tumor malignancy profile between cats and dogs, considering animal-related factors (sex, age, and breed), topography, and geographic location using a mixed-effects logistic regression model. Cats had a higher proportion of malignant tumors (78.7%) than dogs (46.2%), and the malignancy profile was very different regarding tumors’ topographies. The mean age of malignant tumors occurred eight months later than benign ones (9.1, SD = 3.4; 9.8, SD = 3.2), in general. Species (OR = 3.96, 95%CI 3.57: 4.39) and topography (MOR = 4.10) were the two most important determinants of malignancy risk. Female dogs had a higher risk than male dogs (OR = 1.19, 95%CI 1.08: 1.31), which does not appear to be the case in cats (OR = 0.98, 95%CI 0.77: 1.23). Breed contributed significantly to differences in malignancy risk in dogs (MOR = 1.56), particularly in pit bulls and boxers. District of residence was not so relevant in predicting malignancy risk (MOR = 1.14). In both species, the risk of malignancy increased by approximately 20% every three years. It could be hypothesized that species differences in genetic structure may contribute to tumor malignancy.

Cryptorchidism: The dog as a study model

Cryptorchidism (CO) or undescended testicle is an abnormality of male gonadal development that can generate long-term repercussions in men, such as infertility and germ cell neoplasia in situ (GCNIS). The origin of these alterations in humans is not completely clear, due to the absence of an animal model with similar testicular development as in humans with CO. This work intends to describe the testicular histological development of dogs with congenital CO, and determine whether the species could adequately serve as a study model for this pathology in humans. The study was carried out with 36 dogs, equally distributed in two groups: healthy control (CTRL) and CO groups. The contralateral testis to the undescended one in CO group of the animals was considered and analyzed. Each group was subdivided in three stages of development: (1) peripubertal stage (6–8 months), (2) young adult (9–48 months) and (3) senile (49–130 months). Histological development, the presence of cells with gonocyte morphology, cell proliferation, testicular lipoperoxidation and hormonal concentrations of testosterone, estradiol, FSH and LH were evaluated and described. In the cryptorchid testes, the first histological alterations appeared from the first stage of development and were maintained until the senile stage. A pronounced testicular lipoperoxidation occurred only in the second stage of development. The histological alterations due to CO were markedly evident in the young adult stage. Testosterone concentrations witnessed a decrease starting from in the second stage and kept on until the last stage. The contralateral testes of the CO animals showed alterations that positioned them between the control and CO testes. Testicular development of dogs with CO is similar to that of humans. The results of the study suggest that this species could serve as a suitable model for the study of CO in humans.

Canine testicular tumors: An 11-year retrospective study of 358 cases in Moscow Region, Russia

Background and Aim:

Canine testicular tumors are among the most common reproductive tract tumors in male dogs and have been studied in many countries. However, to the best of our knowledge, studies with a large sample size have not been conducted in Russia. This study aimed to provide the latest information on the prevalence of canine testicular tumors in the Veterinary Oncology Scientific Center for Small Animals “Biocontrol” in Moscow, Russia, in 2010-2020 and the characteristics of the affected canine population.

Materials and Methods:

A retrospective review of patients and histological reports was collected and analyzed from 358 dogs with 447 testicular tumors within 11 years.

Results:

The mean age of the affected dogs was 10.4 years, whereas that of dogs with Sertoli cell tumors was 9.4 years p=0.009. This study includes mixed-breed dogs (18.4%), Yorkshire Terriers (8.8%), Labrador Retrievers (7.9%), Golden Retrievers (5.0%), and Fox Terriers (3.4%). The most common tumors were interstitial cell tumors (n=227, 50.8%). In contrast, 107 (23.9%) seminomas, 80 (17.9%) Sertoli cell tumors, 19 (7.4%) mixed germ cell-sex cord-stromal tumors, and 26 (7.6%) testicular tumors developed from cryptorchid testes, which included 16 (61.5%) Sertoli cell tumors, 10 (38.5%) seminomas, and no interstitial cell tumors.

Conclusion:

This study provides baseline information on the prevalence of canine testicular tumors in the described population, including the median age of each tumor type and overrepresented dog breeds. We further found that the most common scrotal testicular tumor was interstitial cell tumor, whereas Sertoli cell tumor was the most common in cryptorchid testicles.

Characterization of Testicular Tumor Lesions in Dogs by Different Ultrasound Techniques

In this retrospective study, we assessed the accuracy of different blood flow imaging in diagnosing testicular tumor types in dogs. We recruited 27 dogs with leydigomas (14), seminomas (eight), sertoliomas (six), and mixed cells (five) confirmed histopathologically. In intact dogs, Pampiniform plexus and marginal arteries were scanned through pulsed Doppler. Blood flow and presence of intralesional/perilesional arteries were assessed by color and power Doppler, B-flow, and contrast-enhanced ultrasound. Tumor types did not differ by B-Mode ultrasonography characters. Pampiniform and testicular arteries of sertoliomas had higher (p < 0.05) pulsatility and resistive indexes. The proportion of leydigomas with a perilesional and/or perilesional/intralesional blood flow pattern detected by color and pulsed Doppler and B-flow was higher (p < 0.05) than that of the other tumors counted together. This resulted in a sensitivity of 81.8%, 83.3%, and 85.7%, a specificity of 76.5%, 56.3%, and 73.7%, and a correct classification rate of 78.6%, 67.9%, and 78.8%, respectively. While contrast enhanced ultrasound was highly effective in detecting all tumors, qualitative and quantitative parameters did not contribute to their differential diagnosis. In conclusion, results indicate that different testicular tumor types of dogs have subtly different vascular patterns, a condition that could help in identifying leydigomas.

Outcome of dogs with bone marrow suppression secondary to Sertoli cell tumour

Sertoli cell tumours are one of the most common canine testicular neoplasia. These tumours are significantly more likely to arise in cryptorchid dogs and are often functional, oestrogen-secreting tumours which can lead to fatal myelotoxicity. The goal of this study was to describe the outcome of dogs with oestrogen-induced bone marrow suppression secondary to Sertoli cell tumours in seven client-owned dogs. Medical records from April 1, 2011 through April 1, 2021 were reviewed to identify dogs that underwent surgical management of a Sertoli cell tumour with documented bone marrow suppression. Overall, 5/7 dogs required transfusion of blood products peri-operatively. Cases 1 and 6 received a transfusion of packed red blood cells (RBC) prior to surgery and case 5 required a transfusion of whole blood. Case 1 also required a transfusion of platelets before surgery. Post-operatively, cases 1 and 2 received packed RBC's and case 6 received two transfusions of whole blood. Case 3 required transfusions of both fresh frozen plasma and platelets post-operatively. All dogs survived to discharge and 6/7 dogs had documented improvement in haematopoietic values. Two dogs remained chronically thrombocytopenic. The median hospital stay was 4 days. One dog died within 4 weeks of surgery from worsening pancytopenia. Survival for greater than 1 year was documented in 4/7 dogs, and one dog was lost to follow-up 4 months post-operatively. One dog remained severely pancytopenic 4 weeks post-operatively and received oral lithium treatment. Improvements in all blood cell lines were observed within the 4 weeks and resolution of pancytopenia within 6 weeks. Historically, the prognosis for dogs with bone marrow suppression secondary to Sertoli cell tumours was guarded to poor. This report documented improved outcomes for dogs that underwent surgery, including one dog that received lithium chloride as treatment for Sertoli cell tumour-induced bone marrow suppression.

Atypical cytomorphologic description of a seminoma in a rabbit

Seminoma is reported as a rare disease associated with specific micro‐morphologic findings. In the present report, we describe the case of a testicular seminoma in a 7‐year‐old Holland Lop rabbit, in which the cytology presented an atypical pattern. Upon presentation, the left testicle was severely enlarged, and the patient also had a history of radiation therapy for a previously diagnosed thymoma. Following excision and histopathology of the abnormal organ, results showed a mixed intratubular‐diffuse pattern with evidence of torsion. Moreover, cytology revealed a cohesive pattern with multiple malignancy criteria. To our knowledge, this is the first published report of a seminoma with these cytologic features.

Immunohistochemical insights into a hidden pathology: Canine cryptorchidism

Cryptorchidism is a common disorder in the canine population with some aspects still unclear. Although the bilateral condition is known to lead to fertility problems and predisposition to testicular cancer, the neoplastic risk for scrotal testis in unilateral cryptorchid dog is controversial. Therefore, the therapeutic approach to the canine unilateral cryptorchid is arbitrary so far. This study aimed to investigate precancerous testicular lesions, such as immaturity and atrophy, and compare them in scrotal and undescended testes using an in-depth diagnostic analysis based on immunophenotypic patterns. With this purpose, 26 adult male dogs of different ages and breeds, affected by unilateral or bilateral cryptorchidism were enrolled. After surgical removal, testes were examined immunohistochemically to assess their positivity for specific markers of the canine foetal/neonatal period, that is vimentin (VIM), cytokeratin (CK), desmin (DES), inhibin-α (INH), and anti-Müllerian hormone (AMH) in Sertoli cells, and placental alkaline phosphatase (PLAP) in germ cells. Except for the ubiquitous VIM, all the markers were more expressed in neoplastic gonads compared to healthy ones (P < 0.05). Similarly, testes detected with Sertoli cell-only tubules as well as with Sertoli cells hyperplasia showed higher expression than gonads without such alterations for CK, DES, AMH and PLAP, and for CK and DES, respectively (P < 0.05). The same trend was observed in undescended respect to scrotal testes even though their positivity was significant only for DES, INH and AMH (P < 0.05). Immunohistochemical positivity found in scrotal testes of unilateral cryptorchid dogs, even in absence of detectable anatomical abnormalities, was suggestive of precancerous lesions. Despite the limited sample size, this study could help to clarify the predisposition to neoplastic development in normally descended testes. These markers expression in adult life could allow identifying the early stages of the testicular carcinogenesis process besides suggesting a precautionary bilateral surgical approach in unilateral cryptorchid dogs.

A Rare Case of Canine Metastatic Spermatocytic Tumor without Sarcomatous and Anaplastic Variants

Spermatocytic tumor is a rare testicular tumor, which is originated from gonocytes. It is characterized by the histological feature of tripartite which is composed of large, medium, and lymphocyte-like small cells. It is well-known that spematocytic tumor is benign, thus a good prognosis is expected after simple resection. Metastatic spermatocytic tumor is extremely rare and usually accompanied by histological variants including sarcomatous changes and anaplastic variants. In this case, however, we report a canine metastatic spermatocytic tumor without prominent sarcomatous changes and anaplastic variants. The mass was composed of three kinds of cells including large, medium, and small cells with high pleomorphism. The neoplastic cells had an indistinct cytoplasmic border and mitotic figures were frequently observed. The primary spermatocytic tumor metastasized to the abdominal organs one month after the resection, and the dog died 13 months after the surgery. Thus, careful follow-up is recommended after surgical resection of canine spermatocytic tumor even though metastasis in spermatocytic tumors is rare.

A five-year cohort study on testicular tumors from a population-based canine cancer registry in central Italy (Umbria)

Canine testicular tumors account for about 90 % of tumors affecting the male genitalia. Seminomas (SEM), Sertoli cell tumors (SCT), and interstitial cell tumors (ICT) are the most common histological diagnoses, but their incidence shows high variability among studies. Our aim is to report the results on the analysis of testicular tumors recorded by the population-based Umbria Canine Cancer Registry (CCR) for a 5-year time period and to assess the value of tumor major diameter, measured during trimming, in discriminating neoplastic from non-neoplastic lesions. The study was conducted on 388 testicular tumors (on 1969 total male tumors) diagnosed in 355 dogs from 2014 to 2018. The median incidence was 35 cases/100,000 dogs, with a proportion equal to 19,7 % of all tumors. The incidence on neutered male dogs was 352/100,000. Most tumors were ICTs (50 %), with fewer SEMs and SCTs (29 % and 17 %, respectively). Only 3 % of tumors were mixed germ cell-sex cord-stromal tumors (MGC-SCST). Ten percent of cases had multiple tumors in the same testicle, with SEM-ICT being prevalent (69.2 %). Tumors in cryptorchid testes were 5.9 % of the total, mostly SCT (60.9 %). Mean age at diagnosis was 10.7 ± 2.7, with similar values for different tumor types. Significant incidence ratios (IRR) were found in Golden retriever (IRR 7.18, CI95 % 4.72-10.92) and in English cocker spaniel (IRR 2.30, CI95 % 1.28-4.13) when compared with mixed breed dogs. A value of 0.3 cm (major diameter) of lesions at the moment of trimming was helpful in discriminating a final tumor histological diagnosis from a non-tumor lesion. Since the number of tumors included in this evaluation was limited, further studies to confirm the diagnostic value of this measure are recommended. Our results provided information on the incidence of canine testicular tumors in Umbria region that can be compared with future results and incidence from other geographical areas if provided with reliable data on the total population, can offer solid information on the incidence and proportion of different tumor types in specific territories, contributing also to the supervision of its inhabitants' health. Moreover, pathological data such as the major diameter of tumors can be obtained and contribute to diagnostic routine and standardization.

Analysis of transcript and methylation levels of INSL3 and RXFP2 in undescended and descended dog testes suggested promising biomarkers associated with cryptorchidism

Cryptorchidism is the most common disorder of sex development (DSD) in dogs. This malformation is associated with reduced fertility and with a higher risk of gonadal cancer. Testicular descent is a complex process, and the functions of many environmental and genetic factors are crucial for the proper migration of fetal gonads into the scrotum. Among these, the hormone INSL3 (insulin-like peptide 3) and its receptor RXFP2 (relaxin family peptide receptor 2) play crucial roles in the transabdominal migration of the testes. The genetic background of canine cryptorchidism is poorly elucidated. The aim of this study was to compare the transcript and methylation levels of INSL3 and RXFP2 genes in undescended and descended testes of isolated unilateral cryptorchids, and in gonads of control male dogs with scrotal testes. Next, we searched for polymorphic variants in the 5'-regulatory regions of both genes associated with predispositions to cryptorchidism. The INSL3 transcript level was significantly higher in the undescended testes than in the descended testes of both the affected and control dogs. On the other hand, the mRNA level of RXFP2 was significantly lower in the retained gonads of cryptorchids than in the scrotal testes. The methylation level of a single CpG site located 15 bp upstream of the translation start codon in INSL3 was significantly higher in the testes of the control dogs than in both gonads of cryptorchids. The methylation level of 14 CpG sites in the coding region of INSL3 was significantly higher in undescended testes than in the scrotal testes, which may be associated with the higher mRNA levels of INSL3 observed in these samples. The methylation pattern of two CpG sites in the 5'-flanking region of RXFP2 was similar in both descended and undescended testes. We detected three and seven single nucleotide polymorphisms (SNPs) in the 5'-regulatory regions of INSL3 and RXFP2, respectively. Among these, the frequency of A > C substitution (ss7093349755) located 495 bp upstream of the transcription start site of RXFP2 differed significantly between cryptorchids and control dogs. Our study showed two possible genetic biomarkers associated with canine cryptorchidism: a hypomethylation of a single CpG site in the 5'-flanking region of INSL3, and the ss7093349755 SNP in the 5'-flanking region of RXFP2.

Altered expression of CYP17A1 and CYP19A1 in undescended testes of dogs with unilateral cryptorchidism

Cryptorchidism is the most common disorder of sex development in dogs and testosterone plays a crucial role in the inguinal phase of the testes descending into the scrotum. The molecular background of impaired testosterone synthesis in the testes of cryptorchid dogs is poorly elucidated. In this study, we analyzed the expression of four genes involved in testicular steroidogenesis (CYP17A1, CYP19A1, HSD3B2 and HSD17B3) in undescended and contralateral scrotal testes from inguinal unilateral cryptorchid dogs (n = 13) and from the scrotal gonads of normal males (n = 15). We found that transcript level of CYP17A1 was significantly increased in inguinal gonads, while the level of CYP19A1 was decreased. For these two genes, we analyzed the methylation level of single CpG sites in the promoter region localized within putative target sites for testicular transcription factors (NUR77, CREB, CAR and HSF2). A correlation between decreased methylation in the promoter of CYP17A1 and its increased transcript level in undescended gonads was observed, but the change in protein level was not significant. We also resequenced the 5'-flanking region of both genes and two known polymorphic sites, SNP in CYP17A1 and an indel in CYP19A1, were found. However, the distribution of the variants in affected (n = 80) and control (n = 75) dogs was not associated with cryptorchidism. We tentatively conclude that the altered expression of CYP17A1 and CYP19A1 in undescended testes could be caused by their exposure to increased temperature in the body. Furthermore, we showed that the identified polymorphisms cannot be considered markers associated with a predisposition to cryptorchidism.

Desexing Dogs: A Review of the Current Literature

Background: Desexing dogs is promoted for population control, preventative healthcare, and behavior modification. Common methods are orchiectomy and ovariectomy/ovariohysterectomy. GnRH superagonist implants are available in some areas. Alternative methods like vasectomy and salpingectomy/hysterectomy are uncommon. The terminology used to describe desexing is inconsistent and contradictory, showing a need for the adaption of standardized terminology. Population Control: Surprisingly, empirical studies show no effects of desexing on population control in companion and shelter dogs despite desexing being consistently recommended in the literature. There is evidence for a population control effect in free-roaming dogs, where desexing also has benefits on zoonotic disease and bite risk. Population control in free-roaming dogs is mostly correlated with female, not male desexing. Health and Lifespan: Desexing affects numerous disease risks, but studies commonly neglect age at diagnosis and overall lifespan, age being by far the most important risk factor for most diseases. We argue that lifespan is a more important outcome than ultimate cause of death. A beneficial effect of desexing on lifespan is consistently demonstrated in females, while evidence for a beneficial effect in males is inconsistent. Studies are likely biased in desexing being a proxy for better care and desexed dogs having already lived to the age of desexing. Desexing reduces or eliminates common life-limiting diseases of the female reproductive system such as pyometra and mammary tumors, while no analogous effect exists in males. Disease risks increases across sexes and breeds include cruciate ligament rupture, various cancers, and obesity. Urinary incontinence risk is increased in females only. Various other disease risk changes show considerable variability between breeds and sexes. Behavioral Effects: Desexed males show reduced libido, roaming, conspecific mounting, and urinary marking frequency, as well as reduced male dog-directed aggression in a majority of males desexed for behavioral reasons. There is a detrimental effect on the risk and progression of age-related cognitive dysfunction. Desexed dogs may be less likely to cause bite injuries across sexes. The evidence for other effects such as human-directed aggression, human or object mounting, resource guarding, or shyness and anxiety is inconsistent and contradictory. There are few studies specific to females or individual breeds. Conclusions: The evidence for a beneficial effect of desexing is stronger in female than in male dogs; however, there is significant variation between breeds and sexes, and more research is needed to further elucidate these differences and to arrive at individualized evidence-based recommendations for clinical practice.

Canine cryptorchidism: An update

This review article is aimed at providing an update on canine cryptorchidism based on the research studies published in this area over the last 26 years. Although a majority of these research studies were directed at investigating the genetic and molecular basis of cryptorchidism, the mechanisms underlying this problem in dogs are still not clear. Future studies using advanced genomic and molecular approaches and including a larger number of dogs of multiple breeds are required to further our understanding of canine cryptorchidism. Diagnosis and treatment of cryptorchidism in dogs have not received much attention. Research advancements include investigation of ultrasonography and anti-Müllerian hormone assay as potential diagnostic methods. Advancements in treatment include the use of laparoscopic-assisted cryptorchidectomy. Based on the available literature, this method appears to be the best for removal of abdominal cryptorchid testes from dogs. However, future studies that compare laparoscopic-assisted cryptorchidectomy with the traditional approaches are required for a more conclusive determination of the best method for cryptorchidectomy in dogs.

Anti-Müllerian hormone: a potentially useful biomarker for the diagnosis of canine Sertoli cell tumours

Background

Testicular tumours are common in dogs and in many cases do not give rise to clinical signs. In other cases, signs of feminization, hyperpigmentation or alopecia may be observed, most commonly associated with Sertoli cell tumours (SCT). Although these signs are often associated with elevated concentrations of oestradiol, analysis of oestradiol may give inconclusive results due to large variations among individuals. Other biomarkers are therefore needed. Anti-Müllerian hormone (AMH) is expressed by the Sertoli cell. In humans, AMH has been shown to be a specific marker of Sertoli cell origin in gonadal tumours. Using immunohistochemistry, AMH has been shown to be a useful marker of immature and neoplastic Sertoli cells in dogs. The aim of the present study was to evaluate the clinical relevance of AMH analysis in peripheral blood in the diagnostic workup of dogs with suspected testicular tumours.

Results

Blood was collected from 20 dogs with a palpable testicular mass and from 27 healthy controls. Serum was analysed for oestradiol-17β using a RIA and for AMH using an ELISA. The Mann–Whitney U test was used to compare hormone concentrations between different groups.

All control dogs had AMH concentrations ≤ 10 ng/mL, except one outlier that had a concentration of 43 ng/mL. Six dogs with SCT or mixed tumours containing SCT had AMH concentrations higher than 22 ng/mL, significantly higher than AMH concentrations in control dogs (P = 0.0004). Concentrations between 10 and 22 ng/mL were found in about half of the dogs with non-neoplastic testicular pathologies or with testicular tumours other than SCTs. Age did not significantly affect concentrations of AMH in the control dogs.

Conclusion

AMH was shown to be a promising biomarker for the diagnosis of Sertoli cell tumours in dogs.

Canine testicular tumors: two types of seminomas can be differentiated by immunohistochemistry

Background

Testicular tumors are the most common genital neoplasms in male dogs, with Leydig cell tumors (LCT), seminomas (SEM), and Sertoli cell tumors (SCT) the most common forms. Human SEM are classified as classical (CSEM) or spermatocytic (SSEM). Intratubular germ cell neoplasia of undifferentiated origin (IGCNU) is another form of human testicular tumor. The aim of this study was to verify that CSEM/SSEM classification is valid in dogs and confirm the existence of canine IGCNU.

Results

Testicular tumors were found in 46% of dogs at necropsy and accounted for 7% of tumors biopsied. The median age of dogs with tumors at necropsy was 10.16 years; median age at positive biopsy was 10.24 years. The most common tumors, in decreasing order, were LCT, mixed tumors, SEM and SCT at necropsy, and SEM, SCT, mixed tumors, LCT, peripheral nerve sheath tumor, and teratoma in the biopsy group. IGCNU was found in 3% of testicles at necropsy and in 3% of biopsy samples. Two dogs had testicular tumor metastasis. Expression of c-KIT was most common in SEM and seminomatous components of mixed tumors. PLAP was mostly expressed in IGCNU, SEM, teratoma, and some mixed tumors. Cytokeratin was mainly expressed in SCT. CD30 expression was low in both groups.

Conclusions

The high tumor incidence at necropsy can be attributed to older age. Tumor incidence in biopsy samples, dog age, and histological classification were consistent with previous studies. The higher incidence of SEM and SCT in the biopsy group probably resulted from the obvious clinical expression of these tumor types. The low incidence of metastasis confirmed the predominance of benign tumors. Low CD30 expression confirmed the low incidence of testicular embryonal carcinoma. Cytokeratin helps differentiate stromal tumors, especially SCT, from germ cell tumors. Histology and c-KIT and PLAP expression indicate that IGCNU exists in dogs. Expression of c-KIT and PLAP confirmed that CSEM and SSEM classification is valid in dogs.

Morphological and immunohistochemical characterisation of seminomas in Norwegian dogs

Background

Seminomas in the dog have traditionally been assumed to resemble human spermatocytic seminomas, based on their low malignancy and high occurrence in old individuals. However, recently published studies indicate that canine seminomas can be classified as classical and spermatocytic seminomas in a similar way as in man, and that classical seminomas comprise a substantial proportion of seminomas in the dog. These two factors both contribute to increasing the potential of canine seminoma as a relevant model for human testicular cancer. The aim of the present study was to characterise seminoma in Norwegian dogs using morphology and immunohistochemistry, and determine whether these tumours are comparable with human classical seminoma.

Methods

By applying diagnostic criteria from human pathology, 45 seminomas from the Norwegian Canine Cancer Register were examined histologically with hematoxylin and eosin (HE) and periodic acid-Schiff (PAS) stains. All sections were stained immunohistochemically with antibodies against human placental alkaline phosphatase (PLAP) and the transmembrane receptor c-KIT.

Results

Although two of the seminomas showed immunohistochemical staining characteristics indicative of classical seminoma (PLAP+/c-KIT+), all 45 examined seminomas were morphologically consistent with spermatocytic seminoma.

Conclusions

The value of canine seminoma as a model for SE in man remains unclear. Among the 45 investigated tumours from Norwegian dogs, none were classified as classical seminoma based on morphological criteria consistent with human seminomas. Regional or breed differences in the occurrence of classical seminoma in the dog, as well as the lack of uniform diagnostic criteria, might explain the discrepancy between the findings in the current study and the results presented by other authors.

Testicular neoplasia in the retained testicles of an intersex male dog

This case describes the presentation and management of an 8 yr old phenotypically female intersex male dog presented for evaluation of a mass in the right inguinal region. The right inguinal space was surgically explored, and a large irregular mass resembling a fully developed testicle was identified in the right vaginal tunic. A second mass resembling an atrophied, but anatomically mature testicle, was identified in the left tunic. The larger mass was identified as a Sertoli cell tumor that had replaced all normal testicular tissue. The smaller mass was identified as a testicle that contained a small intratubular seminoma. The patient was diagnosed as having a phenotypic female sex, chromosomal male sex, and a gonadal male sex. Hormone assays completed before and after the gonadectomy and mass removal document an elevation of circulating progesterone presurgically that returned to baseline by 1 mo postsurgically. The source of the progesterone was identified to be the Leydig cells of the atrophied testicle.

Unusual systemic metastases of malignant seminoma in a dog

Unilateral enlargement of left testicle and scrotum was detected in an 8-year-old West Highland White Terrier. The histopathological diagnosis after surgery was a seminoma (SEM) tumour, and a diagnosis of metastatic foci was also detected in vaginal tunic and scrotum. Two months later, new metastatic SEM foci in the skin were diagnosed. Twenty-two months after the initial orchiectomy new multiple cutaneous nodules and a swelling of periesophageal structures were observed. Finally, the necropsy revealed multiple malignant metastatic SEM focus. To the author's knowledge, this is the first description of a canine SEM with unusual widespread metastasis on the base of tongue, soft palate, trachea and pericardium.

Fibrolipoma of a cryptorchid testis in a young bull

A six-month-old Japanese Black bull was found to have no left testis in the scrotum. A fist-sized mass was palpated per rectum. Two months later, hCG was injected and blood samples were collected before and after injection. No testosterone response to hCG was observed. On the cut surface of the excised mass, most of the mass was composed of homogeneous adipose-like tissue. The rest of the surface was composed of a well-circumscribed testicular parenchyma-like tissue (18 × 16 × 15 mm). Histology revealed diffusely distributed mature adipocytes and septa of fibrous connective tissue. Neither germ cells nor spermatozoa were observed in the seminiferous tubules. A diagnosis was made of fibrolipoma and aspermatogenesis of the left cryptorchid testis.

Laparoscopic-Assisted Cryptorchidectomy in an Adult Reindeer (Rangifer tarandus)

A successful laparoscopic-assisted cryptorchidectomy is reported in a novel species, the reindeer (Rangifer tarandus). The procedure was performed in an 8-year-old adult positioned in dorsolateral oblique recumbency, with an open approach midline subumbilical placement of the primary 10 mm optical port and carbon dioxide insufflation at 12 mmHg. Three 5 mm instrument ports were inserted under visualization in the left caudal abdomen as the retained testicle was localized to the internal inguinal ring. A 5 mm flexible organ retractor was used to assist in localizing the retained testicle. This procedure provided a less invasive alternative to open laparotomy. The authors are unaware of any published reports of laparoscopy in reindeer, or of laparoscopic assisted cryptorchidectomy in deer species.

Spermatocytic seminoma with neuroectodermal differentiation and sertoli cell tumor in a dog

Two distinct nodules developed in a cryptorchid testis of an 8-year-old male West Highland White Terrier. One nodule was a Sertoli cell tumor. The other was a spermatocytic seminoma with focal primitive neuroectodermal differentiation: formation of Homer-Wright rosettes and perivascular pseudorosettes, with immunoreactivity for S-100 protein, neuron-specific enolase, synaptophysin, neurofilament-68 kDa, microtubule-associated protein 2, and vimentin. The dog was alive and healthy 2 years after castration.

Breed differences in the proportional morbidity of testicular tumours and distribution of histopathologic types in a population-based canine cancer registry

Histologically verified tumours submitted to the Norwegian Canine Cancer Register from 1990 to 1998 were studied (n=14,401). The proportion of testicular tumours (n=345) was 2.4%, and the breakdown of histological tumour diagnoses is presented. The frequency of the most common histopathological types was 33% interstitial (Leydig), 26.4% Sertoli and 33.9% seminomas/germ cell tumours. The average age at diagnosis was 10 years, but was significantly lower for Sertoli cell tumours (8.6 years) than for the other tumour types. Following a histopathological re-evaluation, 22.5% of the original tumor diagnoses were modified. Proportional morbidity ratios were calculated and individuals from the breeds Shetland sheepdog and Collie were five times more likely to have testicular tumours than the overall average for the registry. Breed differences in the distribution of histopathologic types were observed. Shetland sheepdog and Collie were most commonly diagnosed with Sertoli cell tumours, while all tumours from Norwegian elkhound in this material were seminomas.