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.     

Simultaneous presence of a seminoma and a leiomyoma in the testes of a horse

An 18‐year‐old stallion was presented for castration because of insidious, bilateral scrotal enlargement of one year's duration. The left testis was firm, while the right was soft and lobulated; both were larger than normal. Palpation of the scrotum and its contents did not cause the horse to show signs of discomfort. Ultrasonography of scrotal contents revealed abnormal, heterogeneous tissue with ill defined regions of hyper‐ and hypoechogenity throughout both testes. Several hours after admission the horse developed severe signs of colic. On the basis of anamnesis, clinical findings, and results of ultrasonography and transrectal palpation bilateral testicular neoplasia and incarcerated inguinal hernia were tentatively diagnosed. Because the horse's owner did not consent to surgical treatment, the stallion was subjected to euthanasia. Histological and immunohistochemical examination of the testicular tissue collected post mortem revealed a seminoma in the left testis and a leiomyoma in the right testis. The post mortem examination also revealed incarceration of the small intestine in addition to the testicular tumours. To our knowledge, this is the first report of the simultaneous presence of bilateral, yet different testicular tumour types in a stallion.     

Malignant seminoma with gross metastases in a dog

A 10-year-old male crossbred dog developed a non-painful unilateral testicular swelling; the other gonad was reduced in size. Both gonads were removed surgically; the larger contained a diffuse seminoma, the smaller atrophic testis contained an interstitial cell adenoma and several intratubular seminomas. Six months after being castrated the dog developed palpable intraabdominal masses. Necropsy revealed gross metastatic malignant seminoma in para-aortic lymph nodes. No histological features were identified to correlate with the malignant behaviour of this usually benign tumour.     

Inguinal-Scrotal Urinary Bladder Hernia in an Intact Male Domestic Rabbit (Oryctolagus cuniculus)

An 8-year-old intact male dwarf rabbit (Oryctolagus cuniculus) was presented with a 2-month history of unilateral scrotal swelling. The external physical examination of the rabbit patient confirmed the severe, unilateral, fluid-filled scrotal distention. Radiographic images of the effected scrotum revealed a soft tissue swelling in the area of the left testicle, and the absence of the urinary bladder in the caudal abdomen. Ultrasonography verified the presence of a fluid-filled mass in the scrotum, enveloping the left testicle. A fine-needle aspiration of the scrotal mass yielded urine, thus a diagnosis of a nonreducible herniation of the urinary bladder into the scrotum was made. An inguinal herniorrhaphy was performed, and the bladder was successfully reduced into the abdominal cavity. A bilateral routine castration and left scrotal ablation were also performed. Two months after surgery no recurrence was noted, and the patient had normal urinary function. Inguino-scrotal bladder herniation is rare in both humans and animals. Male rabbits are predisposed to inguinal and scrotal hernias because their inguinal rings remain open throughout life. Herniation of the urinary bladder should be considered as a differential diagnosis when intact male rabbits are presented with unilateral scrotal swelling.     

Infiltrating Foxp3+ Regulatory T cells and Histopathological Features in Canine Classical and Spermatocytic Seminomas

In humans, regulatory T (T reg) cells are known to play a critical role in both the regulation of immune homoeostasis and the progression of cancer. However, there is little information about the identification, characterization and the function of T reg cells in canine tumours. We identified T reg cells in 28 canine seminoma samples using a Forkhead box P3 (Foxp3) antibody and investigated the relationship between T reg cell infiltration and histopathological features of classical and spermatocytic seminomas (SE and SS, respectively). The Foxp3 protein showed nuclear immunostaining in infiltrating lymphocytes, and Foxp3+ cells were diffused or focally distributed in seminoma tissues. Foxp3+ cells were frequently present in the SS histotype, in seminomas that showed no evidence of tumour cell invasion into the vessels and in seminomas showing a diffuse growth pattern with three cell types. Neither the SE/SS histotype nor the histopathological features of the tumour correlated with Foxp3+ cell counts. These results indicate that Foxp3+ T reg cells may be associated with a less malignant histological phenotype or may not play a critical role in the immune response of canine seminomas. Moreover, Foxp3+ T reg cells may be associated with SS seminoma, but further studies, involving a larger number of samples, are required to better understand whether these cells play a critical role in the immune response in canine seminomas. This is the first report to demonstrate the characteristics of T reg cell infiltration in canine seminoma.     

Bilateral corneoconjunctival dermoids and nasal choristomas in a calf

A 5-day-old Angus x Hereford calf presented for bilateral haired masses on the eyes and nasolabial planum since birth. The masses were surgically excised from the inferonasal cornea and bulbar conjunctiva of both eyes and the left and right side of the dorsomedial nasolabial planum. Histopathology of the excised tissue confirmed bilateral corneoconjunctival dermoids with ectopic lacrimal glands, and bilateral nasal choristomas and ectopic nasal glandular tissue. Surgery was curative and healing was uneventful. Bilateral ocular dermoids in combination with nasal choristomas and ectopic glandular tissue have not been documented previously in cattle.     

Seminoma with cutaneous metastases in a dog

A 10-year-old Great Pyrenees was presented for anorexia and weight loss. On physical examination, the dog was emaciated and showed a large ulcerated lesion on the right lower lip in addition to an enlarged right testicle. Fine-needle aspiration biopsy of the testicle and surgical biopsy of the lip lesion were performed; the histopathological report was consistent with metastatic seminoma. The diagnostic and therapeutic approach in this unusual metastatic seminoma is presented and compared to the previous literature. A multimodality therapy consisting of surgery and chemotherapy is proposed for the clinical management of metastatic seminoma in dogs.     

Lateral hermaphroditism and seminoma in a dog

A 3.6-year-old female Collie was found to have a functionally active ovary and an azospermic testis containing several seminomas. The bitch had had 3 irregular estrous cycles. An ovariohysterectomy was performed, and the histopathologic diagnosis was lateral hermaphroditism and seminoma. Canine intersexes generally have been thought not to have estrous cycles. However, as evidenced in this case, estrous activity can occur. From this report, it is suggested that bitches having irregular estrous cycles should be evaluated for intersexuality.     

Parotid salivary gland adenocarcinoma with bilateral ocular and osseous metastases in a dog

A case of primary parotid salivary gland adenocarcinoma is described in a three-year-old entire female great dane. The presenting complaint was sudden onset blindness concomitant with the development of bilateral hyphaema and anterior uveitis. A soft-tissue swelling of the left subaural region and right forelimb lameness were also present. A definitive diagnosis of primary parotid salivary gland adenocarcinoma with bilateral ocular metastases was made on post mortem examination. Metastases were also present in the right proximal humerus, left and right prescapular lymph nodes, left axillary lymph node, left retropharyngeal lymph node, bronchial lymph nodes and all lung lobes.     

Bilateral malignant seminoma with metastases in the mule: a report of two cases.

We report two cases of bilateral malignant seminoma in the bursula testium of two mules, which had been slaughtered normally. Histologically, the testicular tumours consisted predominantly of large round to polyhedral cells with frequent mitotic figures. Metastases were found in the sublumbar lymph nodes. A final histopathological diagnosis of malignant seminoma with metastasis was made. To our knowledge, this paper appears to be the first report of two cases of bilateral malignant seminoma with metastases, in the mule.     

Intra-abdominal torsion of a neoplastic testicle in a rabbit (Oryctolagus cuniculus) with cryptorchidism

Background: Testicular torsion is a relatively common complication of cryptorchidism in domestic mammals but is currently unreported in rabbits. Case presentation: A 7-year-old Dutch rabbit was examined for sudden anorexia and lethargy. The rabbit was previously diagnosed with unilateral cryptorchidism 5 years earlier; however, the owner declined surgical treatment at that time. Transabdominal ultrasonography showed a structure consistent with an enlarged testis, with decreased echogenicity, and absent blood flow upon color Doppler ultrasonography. After induction of general anesthesia and during preparation for surgery, the patient had an episode of cardiac arrest. After successful resuscitation, bilateral cryptorchidectomy continued as planned. A ventral midline laparotomy was performed and confirmed presence of an enlarged, dark red left testicle torsed on its spermatic cord. The contralateral testicle was atrophic. Both testicles were removed after standard hemostasis. Recovery was uncomplicated. Histopathologic examination revealed a diagnosis of Sertoli cell tumor and extensive hemorrhage and necrosis in the torsed testicle. Conclusions and Clinical Relevance: Based on literature search, this is the first reported case of intra-abdominal torsion of a neoplastic testicle in a cryptorchid rabbit. Early elective cryptorchidectomy before the potential development of life-threating complications may be beneficial in rabbits as in other species.     

IMAGING DIAGNOSIS—BILATERAL ADRENAL ADENOMAS AND MYELOLIPOMAS IN A DOG

A 10-year-old neutered female Pug was evaluated for a left adrenal mass detected previously by ultrasonography. Using computed tomography, a fat-attenuating, rim-enhancing left adrenal mass and a homogeneous, soft-tissue attenuating, intensely enhancing right adrenal mass were found. A left adrenalectomy and right adrenal biopsy were performed and the final diagnosis was bilateral adrenal adenomas and myelolipomas. Myelolipomas are rare, benign, endocrinologically inactive tumors composed of well-differentiated adipose tissue and a variable amount of hematopoietic cells of both lymphatic and myeloid lineages, which may account for the different appearance on tomographic images.     

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.     

Unilateral Seminoma in a Dromedary Camel

A 10‐year‐old, clinically healthy, male dromedary camel had presented a history of progressive unilateral testicular enlargement over the past 5 years. The animal had mated with 32 females during that period; all had conceived. The sex ratio of his offspring was one male to 31 females. Ultrasound examination of the right testicle revealed a diffusely heterogeneous parenchyma with no identifiable normal testicular tissue. The enlarged testicle was surgically removed. Macroscopically, the testicle had a glistening pink surface and contained multiple soft, bulging nodules. Histopathologically, a well‐differentiated, diffuse seminoma was diagnosed. In conclusion, this study describes the fertility, sex ratio, clinical findings and ultrasonographic imaging in a male dromedary camel affected with unilateral testicular seminoma.     

Spontaneous seminoma in medaka (Oryzias latipes)

Although spontaneous development of seminoma is rare in medaka, we encountered spontaneous testicular tumors located within the abdominal cavity in two adult medakas. The growth patterns of the tumors were a combination of solid and cord arrangements in one of the two cases (Case I) and lobular in the other case (Case II). The tumor cells resembled the cells at different stages of spermatogenesis, and a small number of oocyte-like cells were also scattered within the tumor. The tumor with solid and cord patterns showed loss of normal testicular architecture, and the tumor cells had partly invaded the dorsal muscular tissue and metastasized to the liver, kidney, and eye. The tumor with a lobular pattern did not exhibit local invasion or metastasis. The tumors were diagnosed as seminomas based on their histopathological characteristics, and the tumor in Case I was observed to be more malignant than that in Case II.     

Pituitary gland abscess in a horse subsequent to head trauma

A 5-year-old Thoroughbred gelding with recent history of head trauma presented with multiple facial swellings, bilateral mucopurulent nasal discharge, neck pain, inappetence and depression. On computed tomographic examination, lesions within the pituitary fossa and structures adjacent to the right guttural pouch were identified. Soft tissue swelling was seen in the dorsal aspect of the right guttural pouch surrounding several cranial nerves, with fluid-like material in the dependent portions of the right guttural pouch. A CSF sample revealed mild mixed pleocytosis and increased protein concentration. The horse had concurrent periapical disease of the 209-cheek tooth and mild left sinusitis. The horse's demeanour deteriorated requiring euthanasia. Post-mortem examination revealed a pituitary gland abscess.     

IMAGING DIAGNOSIS – SEMINOMA CAUSING LIVER COMPRESSION IN A SPUR‐THIGHED TORTOISE (TESTUDO GRAECA)

A 13‐year‐old male spur‐thighed tortoise (Testudo graeca) was presented with anorexia, apathy, and prolapse of penile tissue. Ultrasonography revealed a large heterogeneous mass in the coelomic cavity, and fine‐needle aspiration demonstrated sperm. Magnetic resonance imaging showed a sharply defined mass originating from the left testis. Appearance and signal intensities were similar to those reported in testicular neoplasms in humans, in particular sharing similarities with seminomas. Necropsy results and histopathological findings were consistent with a seminoma. To the authors’ knowledge this is the first report of the diagnosis of testicular neoplasia in a reptile using imaging techniques.     

Congenital Glossocheilognathoschisis and Persistent Frenula Linguae in a Foal: A Case Report

This paper describes clinical findings and surgical treatment of a foal with multiple craniofacial defects (glossocheilognathoschisis; congenital midline cleft of the lower lip, mandible and tongue combined with bilateral persistent frenula linguae) admitted to the Surgery Clinics of Faculty of Veterinary Medicine, University of Kafkas, Turkey. A thorough clinical examination revealed cleft of the lower lip and mandible combined with glossoschisis (glossocheilognathoschisis) and bilateral extensive and restrictive membranous band (frenula) of tissue at the base of the tongue. Physical examination and radiography of the other organs and tissues of the foal were within normal limits. After sedation and general anesthesia, the persistent frenulas on the right and left parts of the tongue were transected, starting from normal tongue tissue, with the scissors. The tongue was completely freed after the transection of the remaining part of the frenulum, where right and left frenulas united, and the accompanying mucosal tissue on the mandibular symphysis was removed and underlying bone tissue was superficially curetted. Cerclage wire was placed under the mucosa of the mandible and was then passed among two drilled holes below the two incisors. These two pieces of wire were twisted together and anchored over the labial surface of the mandibular symphysis junction. The mandibular symphysis was then stabilized after cerclage wire tensing. A nasogastric tube was placed to permit enteral feeding. The foal was discharged 5 days after surgery. Telephone follow-up revealed that the foal had died 15 days after the surgical intervention.     

Liver Lobe Torsion in Rabbits: 16 Cases (2007 to 2012)

The objective of this retrospective case series was to determine the clinical signs, diagnostic test results, treatment protocols, and outcomes of rabbits treated for liver lobe torsion during a 5-year period at a large referral institution. A total of 16 rabbits diagnosed with liver lobe torsion at Angell Animal Medical Center (Boston, MA USA) during January 2007 to March 2012 were included in the study. The diagnosis of liver lobe torsion was made at surgery, during abdominal ultrasound, or on postmortem examination. Medical records of the subject animals were reviewed for signalment, history, clinical signs, results of clinical pathology testing, diagnostic imaging findings, treatment, surgical and histopathology findings, hospitalization time, and outcome. The most common clinical signs of rabbits diagnosed with liver lobe torsion in this study included anorexia, lethargy, and decreased fecal production lasting 1 day. Lop breeds, particularly mini lops, were overrepresented. Anemia was the most common hematologic abnormality, while elevated levels of alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, and creatinine were the most common serum biochemical abnormalities. Abdominal ultrasonography with Doppler assessment was used in 14 rabbits and provided a diagnosis of liver lobe torsion in all cases. The caudate lobe was involved in 10 rabbits (62.5%, 95% CI: 38.8 to 86.2), followed by the right lateral lobe (n = 5; 31.25%, 95% CI: 8.6 to 53.9), the left lateral lobe (n = 2; 12.5%, 95% CI: 3.7 to 28.7), and the right medial lobe (n = 1; 6.25%, 95% CI: 5.6 to 18.1). Two rabbits had more than 1 torsed liver lobe. Exploratory laparotomy and liver lobectomy were performed in 9 rabbits, and all of them survived. Supportive care alone was provided for 7 rabbits, 3 of which survived. The results suggest that nonspecific clinical signs of anorexia, lethargy, and decreased fecal production, in conjunction with anemia and high serum hepatic enzyme activities, should increase the index of suspicion for liver lobe torsion in rabbits. Abdominal ultrasonography with Doppler assessment is useful to confirm the diagnosis. The long-term prognosis for rabbits undergoing liver lobectomy and surviving the hospitalization period is excellent.     

ULTRASOUND APPEARANCE OF AN EQUINE TESTICULAR SEMINOMA

A 16-year-old thoroughbred stallion developed sudden swelling of the left testicle. The stallion had previously been regarded as a unilateral cryptorchid. Ultrasound examination of the left testicle revealed a diffusely heterogeneous parenchyma. The testicle was diffusely hypoechoic with ill defined regions of hyperechogenicity giving the appearance of hypoechoic nodules throughout the testicular parenchyma. No normal testicular tissue was identifiable. An echogenic band, representing a pseudocapsule could be seen surrounding the testicle. Histopathologic diagnosis a seminoma.