Seminomas of the canine testis. Counterpart of spermatocytic seminoma of men?

BACKGROUND

Dogs develop germ cell tumors of the testis at a relatively high rate. It is not known to what degree these tumors resemble various human testicular neoplasms.

EXPERIMENTAL DESIGN

The epidemiology and morphology of a series of spontaneous canine testicular tumors, collected between 1985 and 1991, was analyzed, and compared with human testicular germ cell tumors. DNA content analysis of representative samples was performed using flow cytometry and image cytometry. Eight human spermatocytic seminomas were studied in parallel.

RESULTS

All canine tumors had the histopathologic features reported as typical for dog testis seminomas. These tumors could show both an intratubular and an invasive component. Most of them were pure (78%), while they could be combined with a Leydig cell tumor, a Sertoli cell tumor, or both. No somatic, placental or yolk sac cells were identified, and there was no carcinoma in situ (CIS). A bimodal age distribution, with a peak around 1 year of age and between 4 and 16 years of age, was found for all pure and mixed testicular tumors, except for those composed of a Leydig cell and a seminoma component. These tumors were all present in dogs older than 7 years, being significantly more older (p < 0.01) than dogs with a pure tumor of either type. All Sertoli cell and Leydig cell tumors were diploid. No consistent peritriploid DNA content, characteristic of human testicular germ cell tumors, was found for canine seminomas, which most often had a diploid DNA content. Human spermatocytic seminomas always contained diploid tumor cells, and showed a relatively low number of high ploidy cells, comparable to canine seminomas of the testis.

CONCLUSIONS

The so-called seminomas of the testis are tumors of old age. Histologically, these tumors are composed of a single cell type with some variation without evidence of differentiation. It is proposed that canine seminoma correspond to human spermatocytic seminomas. It is thought that the Leydig elements in these tumors represent a reactive change rather than biphasic differentiation of a single stem cell capable of germinal and sex-cord cell development.

Rarely occurring spontaneous metastasizing testicular tumors in rats. Histopathologic and ultrastructural features

Testicular tumors are not uncommon in aging rats. However, metastasis from these neoplasms to several distant visceral organs has not been reported. Testicular tumors were observed in a total of 18 (1.34%) Sprague-Dawley rats out of 1340 males examined. Out of these 18 neoplasms, interstitial tumors were observed in 12 rats, of which 11 were benign and one malignant. Spermatic seminomas were observed in two (0.15%) cases (one benign and one malignant). Both rats with malignant testicular neoplasms were sacrified in extremis. Remaining four tumors were classified as mesotheliomas. Detailed gross, histopathologic and electron microscopic features of primary testicular neoplasms with metastases to several distant visceral organs are described and discussed.

20 alpha-hydroxysteroid dehydrogenase activity in canine spontaneous neoplasms

20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) activities in 57 neoplastic tissues surgically removed from dogs were measured. Forty-eight of 57 tumor samples were shown to possess 20 alpha-HSD activity. These tissues were histopathologically classified into 22 benign and 26 malignant tumors. Among these tumors, mixed tumor types demonstrated the higher 20 alpha-HSD activity than epithelial and non-epithelial types, and malignant tumors of each tissue type showed slightly but not significantly higher 20 alpha-HSD activities comparing with the corresponding benign ones. Comparing with the activity of normal tissues examined, the corresponding tumor tissues showed significantly higher 20 alpha-HSD activities. Thus, 20 alpha-HSD activity was found in neoplastic tissues at a considerable high rate and the activity seemed to be higher in pathologically malignant tumors.

Number and size of silver-stained nucleoli (Ag-NOR clusters) in canine seminomas: correlation with histological features and tumour behaviour

Twenty spontaneous canine seminomas were examined. A statistically significant difference (P < 0.01) was detected in both the mean silver-stained nucleolar area/cell and the mean silver-stained nucleolar number/cell between (1) two intraductal seminomas with no signs of invasion, and (2) three intraductal ones with signs of invasion and 15 diffuse-type seminomas (two of which metastasized 3 and 12 months after surgical treatment). Furthermore, the metastasizing seminomas showed a mean silver-stained nucleolar area/cell which was significantly greater than that observed in all the other seminomas examined (P < 0.01). It is concluded that quantitative studies of nucleolar changes are useful in evaluating the biological behaviour of spontaneous canine seminomas.

Interstitial cell (Leydig) tumor in an eland (Taurotragus oryx)

We observed an interstitial cell tumor in an 18-mo-old captive eland bull (Taurotragus oryx) in Tel Aviv, Israel. The histological description of the tumor in the eland was similar to that described in cattle; however, the appearance of a moderate amount of lipid vacuoles in the cytoplasm of the neoplastic cells was uncharacteristic for bovine interstitial cell tumors. The eland also had clinical signs of gynecomastia.

Functional ectopic interstitial cell tumor in a castrated male cat

A 12-year-old male cat that had been castrated at 6 months of age was examined to determine the cause of urine spraying of 2 years' duration. The cat had acquired physical characteristics of a sexually intact male, and its serum testosterone concentration was greater than values expected for a castrated cat. Administration of a variety of medications did not halt urine spraying. At necropsy, an interstitial cell tumor was found in a remnant of a spermatic cord.

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

In a review of 262 neoplasms in 225 dogs, 18 tumors in 16 dogs were mixed germ cell-stromal tumors containing intimately admixed germ cells and Sertoli cells in tubular structures of various sizes. Seven of the 18 neoplasms were predominantly composed of germ cells, and 11 were predominantly composed of Sertoli cells. In 15 neoplasms, the germ cells were more anaplastic than the Sertoli cells, and in three neoplasms, both cell types were anaplastic. Five of the seven mixed-cell tumors with predominantly germ cells had germ cells infiltrating the adjoining tissues. Immunocytochemical studies of all 18 mixed-cell tumors, testes from five clinically normal dogs, six seminomas, and six Sertoli cell tumors revealed that neuron specific enolase (NSE) and vimentin were useful in demonstrating the dual population of the mixed cell tumors by differential staining of the germ cells and Sertoli cells. Half of the tumors stained differentially with desmin. In the normal testes, seminomas, and Sertoli cell tumors, parallel staining of germ cells and Sertoli cells by NSE and vimentin was seen, but only the appropriate tissues stained with desmin. The mixed-cell tumors in this study had morphologic features in common with mixed germ cell-sex cord stromal tumors and gonadoblastomas of human beings; clinically, they had more in common with the former. These mixed cell tumors in dogs should be classified separately.

Frequency of spontaneous tumors in Wistar rats in 30-months studies

Tumors occurring in 450 male and 450 female control rats of the strain Wistar (BOR:WISW (SPF Cpb), breeder: Winkelmann, Borchen) employed in 9 control groups from 7 different 30-month studies were compiled on the basis of histopathology reports. 445 male and 448 female rats were evaluated. The remaining animals were unavailable due to autolysis. A total of 1211 tumors (565 in males, 646 in females) were seen in 716 rats (333 males, 383 females), 251 of which were classified as malignant (100 in males, 151 in females). About 44% of all primary tumors were located in the pituitary and adrenals alone. Average frequencies of primary tumors: pituitary 35.4%, uterus 34.0%, adrenals 26.5%, testes 15.8%, thyroid gland 11.8%, mammary glands 11.4% and 22.5% in females respectively, skin/subcutis 6.3%, ovaries 2.9%, endocrine pancreas 2.5%, hemolymphoreticular system 2.3%, liver 1.9%, heart 1.7% and various other organs showing tumor frequencies of less than 1.5%. Male animals exhibited strikingly more tumors of the adrenals, skin, endocrine pancreas, heart and brain, while pituitary tumors were predominant in females. A comparison of these data with those from 24-month studies in Wistar rats from the same breeder shows a considerable increase above all in the number of primary tumors, the number of tumor bearers as well as the number of tumors in the pituitary, adrenals, testes, mammary glands and heart. An extension of carcinogenicity studies to 30 months probably makes it harder to recognise tumorigenic effects of test substances, at least in some organs, than in two-year studies because of the high and variable spontaneous tumor rates.

Spontaneous neoplasms in aged Sprague-Dawley rats

Incidence of neoplastic lesions in untreated Sprague-Dawley rats (1340 males and 1329 females) used as controls in 17 carcinogenicity studies are tabulated and evaluated. In male rats, the most common neoplasms were benign pheochromocytomas and keratoacanthomas (4.0% in each case) followed by pancreatic islet cell adenomas (3.7%), thyroid parafollicular cell adenomas (3.6%), fibromas and squamous cell papillomas of the skin and hepatocellular adenomas (2.0% in each), malignant lymphoma lymphocytic (1.9%), histiocytic sarcomas (1.4%), and adrenal cortical adenomas (1.2%). In female rats, the most common neoplasms were of mammary gland origin (31.3%: fibroadenoma 19.0%, adenocarcinomas 8.8%, and adenomas 3.5%) followed by thyroid parafollicular cell adenomas (2.9%), uterine endometrial stromal polyps (2.6%), adrenal cortical adenomas (1.9%), malignant lymphoma lymphocytic (1.6%), fibromas in the skin (1.3%), and pancreatic islet cell adenoma (1.1%). Metastases were observed from pheochromocytomas, hepatocellular carcinomas, nephroblastomas, renal pelvis transitional cell carcinoma, interstitial cell tumor and seminoma of the testes, Zymbal's gland adenocarcinomas, and mammary adenocarcinomas.

Bone marrow hypoplasia in a feminized dog with an interstitial cell tumor

Bone marrow hypoplasia and feminization developed in a 10-year-old male German Shepherd Dog with interstitial cell tumor. Clinical abnormalities included pyrexia, pale mucous membranes, signs of abdominal pain, large left testis, atrophied right testis, and feminization. Abnormal laboratory findings included pancytopenia, bacteremia, bacteriuria, and pyuria. Results of cytologic examination of a bone marrow aspirate were consistent with aplastic anemia. Serum estradiol concentration was high, and serum testosterone concentration was low, compared with normal values for male dogs. The left testicular mass was identified as an interstitial cell tumor. Other causes of the aplastic anemia or feminization were not found.

Spontaneous seminoma in an owl monkey in captivity

An adult male Aotus nancymae maintained for breeding purposes was submitted for surgery and the left testicle was removed. The surgically removed mass was about two to three times the size of a normal adult owl monkey testicle. Grossly, on cut surface, the mass was soft, white to pale gray, and bulged above the adjacent tissue. Microscopically, the morphology of the tumor cells was consistent with a seminoma.

Mesothelioma in cattle: eight cases (1970-1988)

Over an 8-year period, 8 beef cattle with mesothelioma were admitted to the Auburn University College of Veterinary Medicine and the Louisiana State School of Veterinary Medicine. Diagnosis was confirmed by histologic examination of affected tissues. Five bulls, 1 steer, and 2 cows were affected. Four of the bulls had scrotal swelling; 2 cows and 1 bull had ventral abdominal swelling. The peritoneal cavity was involved in 5 cases, the pleural cavity was affected in 2 cases, and in 2 cases, disease was apparently confined to the vaginal cavity. Of the 8 cattle, 6 died or were euthanatized; only cattle with tumor apparently confined to the vaginal cavity survived.

Ultrasonographic features of testicular neoplasia in dogs: 16 cases (1980-1988)

For 16 dogs with testicular neoplasia (n = 19 tumors), ultrasonography was performed to determine whether a correlation exists between ultrasonographic features of testicular tumors and cell type. The echogenicity of the tumors varied depending on the size of the tumor and whether the tumor had focal or diffuse distribution within the testis. The ultrasonographic characteristics of Sertoli cell tumors were variable, with no predominant pattern. This variation may be related to tumor size, because 6 of 7 Sertoli cell tumors were greater than 5 cm in diameter. Focal seminomas and interstitial cell tumors less than 3 cm in diameter had hypoechoic texture. Focal seminomas and interstitial cell tumors greater than 3 cm in diameter had mixed echogenicity. Tumors of multiple cell types were greater than 5 cm in diameter and had mixed echogenicity. In valuable breeding dogs with a small (less than 3 cm) focal intrascrotal lesion, testicular ultrasonography would be of benefit for localization of the mass to the testis or epididymis for subsequent biopsy. In dogs with intraabdominal neoplastic testes, ultrasonography may be of benefit in determining intra-abdominal metastases and invasion of contiguous structures.

Spontaneous rete testis adenocarcinoma in a Fischer 344 rat: a cytomorphological and ultrastructural study

The report consists of a cytomorphological and ultrastructural description of a spontaneous rete testis adenocarcinoma observed in a 108-week-old Fischer 344 rat. This tumour is considered to be very rare in rats. Crucial evidence for the malignancy of this tumour was the penetration of a neoplastic gland into the tunica albuginea.

The isolation of Brucella melitensis biovar 3 from a testicular hygroma of a ram in a nomadic flock of sheep and goats in western Sudan

Brucella melitensis biovar 3 was isolated from a testicular hygroma in a ram from a nomadic flock of sheep and goats serologically positive for brucellosis and with a history of occasional abortions. The affected testis was enlarged, extensively damaged and contained fluid. The isolation of this biovar identifies the need for further investigations into the prevalence of brucellosis and the particular biovars involved in nomadic animals.

Malignant Sertoli and Leydig cell tumour in a boar

A rare case of Sertoli and Leydig cell tumour was investigated in a 6-month-old boar. The neoplasm was found in the right testis and had metastasized to the liver, spleen, kidneys and diaphragmatic peritoneum. Metastatic nodules were also present in the tissues near the right testis and some neoplastic cells were present in the superficial inguinal lymph node. The neoplastic cells exhibiting severe pleomorphism were divided into Sertoli and Leydig cell types, although in some sites, it was not possible to classify tumour cells clearly as Sertoli or Leydig in type. In the metastatic lesions there were anaplastic Sertoli cells with abundant collagen fibres. Some neoplastic Sertoli cells and a few neoplastic Leydig cells revealed cytoplasmic reactivity for testosterone. Ultrastructurally, the neoplastic cells were characterized by mitochondria with tubulovesicular cristae, smooth endoplasmic reticulum, membranous structures, lysosomes, lipofuscin granules or lipid droplets.

Excess of seminomas observed in Vietnam service U.S. military working dogs

During the Vietnam War, US military working dogs served with their companion dog handlers in close proximity, sharing common exposures to war-related activity, many zoonotic infectious agents, chemical pesticides, phenoxy herbicides, and extensive use of therapeutic drugs. To gain insight into the effects of the Vietnam experience, we investigated the occurrence of neoplasms in military working dogs based on standard necropsy examination by the Armed Forces Institute of Pathology. We observed that these dogs experienced significant elevated risks for testicular seminoma and, independently, testicular dysfunction. Experimental evidence shows testicular dysfunction and impaired spermatogenesis in laboratory animals exposed to phenoxy herbicides, dioxin, or tetracycline, and antibiotic used extensively in military working dogs in Vietnam. Because an unexplained significant decrease in sperm quality in Vietnam veterans has been observed by the Centers for Disease Control, further research is warranted if we are to clarify military service in Vietnam as a risk factor for testicular dysfunction. The testis should be made a priority site in the study of Vietnam experience-related cancers.

Seasonal changes in serum gonadotropin, testosterone, 11-ketotestosterone, and estradiol-17 beta levels and their relation to tumor burden in gonadal tumor-bearing carp x goldfish hybrids in the Great Lakes

The hybrids of carp (Cyprinus carpio) and goldfish (Carassius auratus) collected from the lower Great Lakes between 1978 and 1981 exhibited a high frequency of gonadal neoplasms and apparent sterility, conditions which were rare in the parental species. A pronounced hyperplasia of gonadotropic cells in hybrids resulted in the accumulation of large stores of biologically active gonadotropin (GtH) in the pituitary gland. Serum GtH levels were generally higher in hybrids than in carp collected from the same areas, but seasonal trends were similar for both species. Among hybrids, tumored individuals had higher serum GtH levels than nontumored individuals. Serum levels and seasonal trends for testosterone (T), 11- and ketotestosterone (11-KT), and estradiol-17 beta (E2) were, for the most part, similar when carp and nontumored hybrids of the same gender were compared. Serum levels of T and 11-KT (but not E2) were generally higher in tumored hybrids when compared to nontumored individuals. High serum steroid levels were related to a specific tumor type, possibly of Sertoli cell origin. Although the etiology of the gonadal tumors is not yet known, the serum levels of gonadal steroids in hybrids make it unlikely that a lack of steroidal feedback is responsible for the gonadotrop hyperplasia.

Malignant seminoma in a cryptorchid stallion

A 16-year-old cryptorchid Quarter House with colic had a large, lobulated soft-tissue mass to the left of the pelvic inlet. At surgery, 2 large multilobulated pedunculated masses were removed. A large blood vessel enveloped by one of the masses was damaged, and the horse exsanguinated. Postmortem examination of the abdomen revealed the masses to be malignant seminoma, with multiple sites of metastasis.