A clinicopathologic, histologic, and immunohistochemical study of mixed germ cell-stromal tumors of the testis in 16 dogs

Testicular tumors in commercial boars with infertility: A gross, histologic, and immunohistochemical study

Tumors in boars are uncommon, and testicular tumors even rarer. This study describes the pathological and immunohistochemical characteristics of a case series of testicular tumors in commercial boars with fertility problems. Tumors were detected in 19 of 333 animals (19/333, 5.9%). Macroscopically, tumors were observed in 13 (13/19, 68%) boars, while 6 cases (6/19, 32%) were only detected by microscopic examination. Testicular enlargement was observed in 1 boar, while in the others, tumors were only observed after removal of the scrotal skin or after sectioning of the testis. Histologically, tumors were classified as seminomas (16/19, 84%), mixed germ cell-stromal tumors (2/19, 11%), and B-cell lymphoma (1/19, 5%). Seminomas had 3 different growth patterns: intratubular (6/16, 38%), diffuse (4/16, 25%), and intratubular/diffuse (6/16, 38%). All tumors that were not evident on macroscopic examination were intratubular seminomas. Intratesticular metastases were observed in 2 cases and extratesticular metastases, located in the pampiniform plexus, were observed in 1 case. In 1 seminoma, the rete testis was also involved. By immunohistochemistry, all intratubular seminomas were negative for c-kit, cytokeratin, and vimentin. In diffuse seminomas, c-kit and cytokeratin were also negative, while vimentin showed granular or perinuclear cytoplasmic labeling in some areas. PAX-5 and CD-3 antibodies classified the lymphoma as a B-cell lymphoma. This study suggests that testicular tumors in boars may be more common than previously reported, especially when microscopic examination is performed. It also shows that testicular tumors in pigs are predominantly seminomas.

An Unusual Case of Collision Testicular Tumor in a Female DSD Dog

Collision tumors (CT) consist of two independent neoplasms with distinct neoplastic populations. Disorders of sexual development (DSDs) are characterized by atypical sexual development leading to various abnormalities of the genital tract. Sex reversal (SR) syndromes are a type of DSD characterized by a discrepancy between chromosomal sex and gonadal development (testes/ovaries) and the presence or the absence of the SRY gene. A phenotypically female 8-year-old Jack Russell terrier dog was referred due to anomalous vaginal discharge and non-pruritic cutaneous bilateral symmetrical alopecia on the flanks. During abdominal palpation, a voluminous mass was detected in the left quadrant area, later confirmed by ultrasound. The owner decided to proceed with euthanasia and necropsy. In the abdominal cavity, the left gonad was increased in size, the right one and the uterus were decreased, and the vagina and vulva appeared to be thickened. Histologically, both gonads were revealed to be testes: the left one was affected by a double neoplastic component (sustentacular tumor and interstitial cell tumor), whereas the right gonad showed coarctated seminiferous tubules. PCR amplification of the genes SRY and AMELX revealed the absence of the MSY region of the Y chromosome. To the authors’ knowledge, this is the first report describing a case of a testicular collision tumor in a DSD SRY-negative dog.

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.

A case of neoplastic synchronism in a dog

INTRODUCTION

Synchronous primary tumors are considered severe, comorbid conditions in people representing neoplasm that develop independently and concomitantly. A diagnosis of synchronous tumors was made in a dog, underlying the difficulties to reach it without the aid of multiple diagnostic techniques aimed to demonstrate the simultaneous coexistence of different tumor types.

MATERIALS AND METHODS

A 7-year-old male Boxer dog presented several tumors located on the skin of the left hind limb and the scrotal region. Moreover, additional tumors in the testicles, after palpation and ultrasound examination, were detected. Following diagnostic results, the cutaneous tumor, scrotum, and testes were surgically removed.

RESULTS

Pathological investigations revealed the presence of five different tumors: a cutaneous mast cell tumor; a scrotal melanocytoma; three testicular neoplasms (Sertoli Sustentacular cell tumor, seminoma, and interstitial Leydig cell tumor).

CONCLUSIONS

The present report describes a neoplastic synchronism due to the presence of five different primary tumors in a dog and, for the first time the presence of a collision testicular tumor together with other non-testicular primary tumors. The occasional finding underlines the importance of the knowledge of such conditions in the process of decision-making and in carrying out all the proper diagnostic procedures for a correct diagnosis and clinical staging.

Histological and immunohistochemical characterization of 17 gonadal tumours in koi carp (Cyprinus carpio koi)

Reports on abdominal tumours in koi carp are scarce and most are from the gonads. Their histological diagnosis is challenging due to the occurrence of mixed populations of neoplastic cells and the few availability of cross-reactive antibodies in fish tissues. The present study aims to provide a histopathological characterization of seventeen gonadal tumours, enriched by a wide antibody panel (vimentin, CD117, placental alkaline phosphatase-PLAP, AE1/AE3 cytokeratin, E-cadherin, proliferating cell nuclear antigen-PCNA, müllerian-inhibiting substance-MIS, GATA4 and Inhibin-α) applied on whole and tissue microarray (TMA) sections. Abdominal enlargement was associated with tumours filling 30%-80% of the abdominal cavity; frequently, the gonads had been completely replaced by neoplastic tissue. Twelve cases were characterized as sex cord-stromal tumours (SCSTs), three as germ cell tumours (GCTs), one as mixed germ cell sex cord-stromal tumour (MGCSCST) and one as carcinoma. By immunohistochemistry, PLAP enabled confirmation of GCTs, ovarian carcinoma and the objective identification of a further cell component in 8 out of the 12 SCSTs that were reclassified as mixed tumours. The use of an immunohistochemical panel can help in refining the histological diagnosis, but the morphological diagnosis still represents the main tool for the characterization of these tumours in koi carp.

Identification of a Novel Zebrafish Mutant Line that Develops Testicular Germ Cell Tumors

Testicular tumors are the most common solid malignant tumors in men 20-35 years of age. Although most of testicular tumors are curable, current treatments still fail in 15%-20% of patients. However, insufficient understanding of the molecular basis and lack of animal models limit development of more effective treatments. This study reports the identification of a novel zebrafish mutant line, ns1402, which develops testicular germ cell tumors (TGCTs). While both male and female ns1402 mutants were fertile at young age, male ns1402 mutants became infertile as early as 9 months of age. This infertility was associated with progressive loss of mature sperm. Failure of spermatogenesis was, at least in part, explained by progressive loss of mature Leydig cells, a source of testosterone that is essential for spermatogenesis. Interestingly, TGCTs in ns1402 mutants contained a large number of Sertoli cells and gene expression profiles of Sertoli cells were altered before loss of mature Leydig cells. This suggests that changes in Sertoli cell properties happened first, followed by loss of mature Leydig cells and failure of spermatogenesis. Taken together, this study emphasizes the importance of cell-cell interactions and cell signaling in the testis for spermatogenesis and tissue homeostasis.

Multiple primary testicular tumours in the dog – a case report

A 13-year old male Poodle dog was presented with a considerable disparity in the size of testes. Palpation demonstrated enlargement of the right testicle; smooth surface without any sign of nodular hyperplasia was detected. Both testes were removed, the enlarged one was sent to a histopathology laboratory. Microscopic examination revealed massive neoplastic proliferation of the testicular germ cell tumour (seminoma) and an accompanying smaller tumour originating from the interstitial Leydig cells (Leydigoma), which was confirmed by immunohistochemistry. Simultaneous occurrence of two different types of tumours in testes is possible, representing a multiple primary malignancy case, which is a rare phenomenon in veterinary practice.

Histologic and Immunohistochemical Characterization of a Testicular Mixed Germ Cell Sex Cord-Stromal Tumor and a Leydig Cell Tumor in a Dog

Mixed germ cell sex cord-stromal tumors (MGSCTs) of the testis are rare in dogs. We describe the histopathology and immunohistochemical characteristics of an MGSCT associated with a Leydig cell tumor in a cryptorchid testis. Histologically, MGSCT consisted of two nodules of seminiferous tubules lined by germ cells and Sertoli cells in variable proportions. Germ cells had variable size and nuclear features, with frequent giant cells. Germ cells were evenly mixed with Sertoli cells or located in the center of tubules. Markers that labeled mainly germ cells and few or no Sertoli or Leydig cells were calretinin, KIT, and PGP 9.5. E-cadherin, GATA-4, inhibin-α (INH-α), and neuron-specific enolase (NSE) were predominantly detected in Sertoli cells, whereas melan A was particularly expressed in Leydig cells and vimentin in all three cell types. OCT3/4 was not detected in any cell type. Although more cases of canine MGSCT need to be examined, our results suggest that an immunohistochemical panel of E-cadherin, GATA-4, INH-α, KIT, NSE, PGP 9.5, and melan A will help distinguish the three main cell types in canine testicular germ cell and sex cord-stromal tumors.

Spermatogonial Nature of the Germ Cell Component of Canine Testicular Mixed Germ Cell-Sex Cord Stromal Tumours

The present study has characterized the germ cell component of canine testicular mixed germ cell-sex cord stromal tumours (MGSCTs) by examining the histological nature and histochemical and immunohistochemical features using gonocytic and spermatogonial cellular markers, c-Kit, placental alkaline phosphatase (PLAP), protein gene product 9.5 (PGP9.5), Sal-like protein 4 (SALL4), and the periodic acid-Schiff (PAS) reaction. Histologically, all 45 examples of MGSCTs were classified as spermatocytic seminomas (SSs) and Sertoli cell tumours in combination. The germ cell component of all MGSCTs was negative by PAS staining. Immunohistochemically, PLAP immunoreactivity was lacking in the germ cell component of all MGSCTs, which is not consistent with a gonocytic origin. The germ cell component was positive for PGP9.5 and SALL4 in all MGSCTs and positive for c-Kit in 53% of MGSCTs, which is consistent with the phenotype of spermatogonia. Furthermore, the germ cell component in 71% of MGSCTs had moderate immunoreactivity for SALL4, which is suggestive of a spermatogonial phenotype. Conversely, 29% of cases had a minor population of germ cells showing strong SALL4 immunoreactivity, suggesting a phenotype similar to prespermatogonia. The results suggest that the germ cell component of canine MGSCTs is morphologically classified as SS, with the majority of cases showing the spermatogonial phenotype and some cases containing a small population of prespermatogonia.

Mixed germ cell-sex cord-stromal tumor with a concurrent interstitial cell tumor in a ferret

A 5-year-old male ferret presented with an enlarged canalicular testis in the left inguinal region. Microscopically, the enlarged testis consisted of a diffuse intimately admixed proliferation of c-kit-positive germ cell-like and Wilms tumor-1 protein-positive Sertoli cell-like components, but no Call-Exner body was detected. In addition, the compact proliferation of steroidogenic acute regulatory protein-intense positive interstitial cells was identified in a separate peripheral area of the mass. Based on histopathological and immunohistochemical findings, the tumor was diagnosed as a mixed germ cell-sex cord-stromal tumor with a concurrent interstitial cell tumor.

First report of a malignant collision skin tumour with malignant melanoma and anaplastic sarcoma components in a dog

This paper describes the occurrence of a rare skin tumour that has been removed surgically from the upper lip of a 13-year-old Tibetan spaniel. The tumour was 0.5 cm in diameter and macroscopically appeared as a single dermal mass, but histopathological analysis identified it as a biphasic collision mixed tumour. In the anatomically uniform tumour, 70% (4 mm in diameter) of the total parenchyma was formed by a high-grade sarcoma (with the presence of giant cells), and about 30% of it (1 mm in diameter) was a malignant melanoma (again with the presence of giant cells). The histologically distinct, but anatomically uniform tumour parts were separated by a macroscopically invisible, non-neoplastic epithelial process originating from the overlying hyperplastic epidermis. The two malignant components did not infiltrate the peritumoural vessels and each other's substance. In the sarcoma part, the mitotic and apoptotic indexes were 32 and 8, respectively, whereas in the melanoma part the same parameters were 10 and 6, respectively. During the immunohistochemical investigations anti-α-SMA, anticytokeratin AE1-AE3, anti-Melan-A, anti-Ki-67 and anti-claudin-5 antibodies were applied. In conclusion, this is the first report of a primary cutaneous malignant biphasic collision mixed tumour formed by an anaplastic sarcoma with giant cells and a malignant melanoma.

Spontaneous sertoli cell tumor with cryptorchism in a beagle dog

A male one year-old beagle dog with unilateral cryptorchism was presented for investigation of reduced appetite. Abdominal sonography and radiography demonstrated abnormal enlargement of the left testicle in the abdominal cavity. Both the retroperitoneal cryptorchid testicle and the other contralateral testicle were removed surgically. The retroperitoneal cryptorchid testicle was an enlarged, firm and bulging sphere mass. The cut surface revealed a homogeneous white color. The contralateral testicle in the scrotum showed an almost normal appearance. Histopathologically, the retroperitoneal cryptorchid testicle was diagnosed as a Sertoli cell tumor. This report describes a case of Sertoli cell tumor with cryptorchism in a beagle dog.

Biphasic malignant testicular sex cord-stromal tumor in a cotton-top tamarin (Saguinus oedipus) with review of the literature

A 20-year old male cotton-top tamarin (Saguinus oedipus) was presented with unilateral enlargement of an intrascrotal testicle. Fine-needle aspiration cytology demonstrated a neoplastic population with Call-Exner-like bodies and features of malignancy. The animal was castrated, and histologic examination revealed a biphasic sex cord-stromal tumor, with one region resembling Sertoli-cell tumor and one region resembling granulosa-cell tumor, with extensive microfollicular pattern and many Call-Exner bodies. Eight months after castration, the animal was euthanized on discovery of a caudal abdominal mass that displaced organs, was highly infiltrative, and extended into the paravertebral musculature with lysis of vertebral bone. Metastases to lymph node and lung were also present. Histologic examination of the abdominal tumor showed multifocal formation of Call-Exner bodies in an otherwise highly dedifferentiated population. Positive immunolabeling for alpha inhibin confirmed the sex cord-stromal origin of the abdominal and paravertebral tumor masses. This case has similarities to malignant testicular granulosa-cell tumor of humans.

Prostatic squamous metaplasia in a cat with interstitial cell neoplasia in a retained testis

An 11-year-old cat with a retained testis was presented with a chronic history of dysuria and bladder atony. Medical therapy failed to alleviate the clinical signs. Contrast radiography demonstrated a diffusely narrowed urethra. During a celiotomy and prepubic urethrostomy, a retained testis, stenosed urethra, and irregularly enlarged prostate were observed. Histopathologic diagnosis was retained testis with a well-differentiated interstitial cell tumor, a poorly differentiated interstitial cell tumor, and marked squamous metaplasia of the prostatic epithelium with suppurative prostatitis. Neoplastic interstitial cells were immunoreactive for Melan A, consistent with reports of Melan A expression in steroid hormone-producing tissue. This is the first report of prostatic squamous metaplasia associated with testicular neoplasia in a felid.

Expression of connexin 43 in normal canine testes and canine testicular tumors

In human testis, gap junctions containing connexin(Cx)43 are located within the seminiferous epithelium between Sertoli cells and between Sertoli and germ cells. Cx43 is known to play a role in the differentiation and proliferation of these cell types. It can further be associated with human seminoma development. The dog has been proposed as a model for studies of the male reproductive system, because of the frequent occurrence of testicular neoplasms. Thus, we investigated Cx43-mRNA and -protein expression in testes of normal prepubertal dogs, adult dogs, and in canine testicular tumors. Sertoli cells in prepubertal cords express Cx43 mRNA, but do synthesize only less Cx43 protein. Within the seminiferous tubules, Cx43 mRNA was detected in Sertoli cells, spermatogonia, and spermatocytes. Cx43 protein was mainly present in the basal compartment. In canine testicular tumors Cx43 mRNA was detectable in both seminoma and neoplastic Sertoli cells, whereas Cx43 protein was only found in neoplastic Sertoli cells. Our data indicate that Cx43 is regulated differentially in testicular tumors and that alterations of Cx43 expression may be involved in the pathogenesis of canine testicular malignancies. This study represents the first morphological work on the spatiotemporal expression pattern of Cx43 in normal and neoplastic canine testis.

Cytologic Features of Testicular Tumours in Dog

In this paper, we report on our experience of cytology of fine needle biopsies performed on 92 dogs with testicular tumours during the period from 1998 to 2002. Cytological diagnosis was consistent with seminoma in 20 cases, sertolioma in 16 cases, Leydig cell tumours in 50 cases and mastocytoma in one case. Five cases could not be diagnosed by cytology. Cytological observations were confirmed after surgery by histopathological examination in 87 cases. Cytology provided a sensitivity of 95% for seminoma, 88% for sertolioma and 96% for Leydig cell tumours. The specificity was 100% for all three tumour types. In our experience cytology of fine needle aspirations of testicular tumours is a very reliable technique.

Sertoli Cell Tumour in a Cat

A Sertoli cell tumour occurred in a cryptorchid testis of a 1-year-old cat with no signs of feminization. The tumour showed intratubular growth without interstitial infiltration and the neoplastic cells appeared polymorphous and vacuolated. Mitotic figures were rare. The diagnosis was based on histopathological, ultrastructural and immunohistochemical features of the tumour cells.

Bilateral Gonadoblastomas in a Dog with Mixed Gonadal Dysgenesis

Gonadoblastomas are rare mixed germ cell neoplasms, which are frequently diagnosed in testes excised for other reasons. In human patients these tumours are usually associated with undescended testes or dysgenetic gonads. This report describes a 10-year-old male dog with mixed gonadal dysgenesis ("streak testis" on the right side and testis on the left side) and bilateral gonadoblastomas. Immunohistochemical analysis revealed an atypical and mitotically active germ cell population which co-expressed placental alkaline phosphatase and c-kit oncogene, admixed with inhibin- and S-100 protein-positive sex cord cells. The findings were generally consistent with previous reports of the dual population of neoplastic cells in gonadoblastomas affecting human patients, and closely resembled the findings in the only other case reported in dogs. Moreover, the findings further support the proposal that gonadoblastomas should be considered a special form of in-situ germ cell neoplasia.

Malignant Sertoli cell tumor in the retained abdominal testis of a unilaterally cryptorchid horse

A 13-year-old Morgan gelding was evaluated because of a mass in the caudal region of the abdomen. The horse had been presumed to be a gelding, but necropsy findings revealed a retained testis in the right retroperitoneal space. Histologically, the retained testis contained neoplastic cells; metastases were identified in the liver, spleen, lungs, and sublumbar lymph nodes. Immunohistochemical examination of the testis and metastatic tissues confirmed the diagnosis of malignant Sertoli cell tumor. Testicular neoplasms are infrequently reported in stallions. Seminomas are most commonly reported, whereas Sertoli cell tumors are considered to be rare. Typical biological behavior of Sertoli cell tumors in horses is unknown. To the authors' knowledge, there have been 2 reports of Sertoli cell tumors in horses; the tumors developed in descended testes, and 1 tumor was malignant.

Reproductive oncology

The actual incidence of reproductive tract tumors is difficult to ascertain, presumably because a significant percentage of dogs and cats are neutered, particularly in the United States. Data from European countries, where elective neutering is less common, provides insights. Several studies document the relative frequency of reproductive tumors. Larger studies of the more common tumors, e.g., testicular tumors, provide a substantial amount of information on the clinical presentation and response to treatment of dogs, but overall there is less information available on cats. Numerous case reports document the less commonly reported tumors and will be included in the following discussion.

Sertoli cell tumour in an Amur tiger

The histological and immunohistochemical characteristics of a malignant Sertoli cell tumour in a 17-year-old Amur tiger (Panthera tigris altaica) are described. Histological examination of the primary lesion in the right testis and metastatic lesions throughout the internal organs showed a variable cellular pattern with an admixture of tubular structures divided by fine stroma filled with fusiform to stellate cells, and sheets of polygonal cells with abundant vacuolated cytoplasm. Immunohistochemical techniques demonstrated strong positive staining for neuron-specific enolase and variable positive staining for vimentin in neoplastic cells, supporting a diagnosis of a tumour of Sertoli cell origin.

A poorly differentiated germ cell tumor (seminoma) in a Long Evans rat

A large neoplasm that replaced 1 testis of a Long Evans Rat was noted at the final necropsy of a dietary 2-yr study. By light microscopy, the morphological features were consistent with a poorly differentiated seminoma. Ultrastructurally, the cells were polygonal, had a round nucleus, had straight cellular boundaries, and bore no resemblance to Sertoli cells. Although there was little evidence of spermatocytic differentiation, the presence of proacrosomal granules and vesicles, prominent Golgi apparatus, tight intercellular junctions, and a few centriolar pairs without axoneme development, in conjunction with the absence of lipid droplets or abundant smooth endoplasmic reticulum, supported the diagnosis of seminoma rather than Leydig cell tumor. The cells were S-100- and vimentin-positive, although cytokeratin- and alpha-fetoprotein-negative. Seminomas are extremely rare neoplasms in rats; this is the first report in this strain and the first extensive analysis of a rat seminoma without spermatocytic differentiation.

Immunophenotype of the canine transmissible venereal tumour

The canine transmissible venereal tumour is a naturally occurring contagious round-cell neoplasia which is primarily located in the mucous membrane of the external genitalia in dogs of either sex. In order to specify the controversial cytogenetic origin of this round-cell tumour, 14 cases of canine transmissible venereal tumour, formalin- or Bouin-fixed and paraffin-embedded, were subjected to extensive immunophenotypic analysis using reagents specific to a variety of cytoplasmic or surface antigens: lysozyme, ACM1 antigen, vimentin, neuron-specific enolase, glial fibrillary acidic protein, desmin, alpha smooth muscle actin, CD3, IgG, kappa and lambda light chains, and keratin. Lysozyme immunoreactivity was detected in all cases, ACM1 antigen in 11 of 14, neuron-specific enolase in 11 of 14, vimentin in 10 of 14, glial fibrillary acidic protein in 4 of 14 and desmin in 1 of 14. All the sections were negative to keratins, alpha smooth muscle actin and CD3, whereas in five cases, perivascular tumour cells contained Ig G, kappa and lambda light chains. The immunoreactivity to lysozyme and ACM1 antigen supports the hypothesis of a histiocytic immunophenotype for the canine transmissible venereal tumour.