OCCURRENCE OF GERM CELL NEOPLASIA IN MALE STRIPED BASS (MORONE SAXATILIS) UNDER HUMAN CARE IN A PUBLIC AQUARIUM: SURGICAL TREATMENT AND OUTCOME.

The striped bass (Morone saxatilis) has been a fish species of special concern in Canada since its marked decline in the early 21st century in the St. Lawrence River. Individuals kept in public aquaria contribute to public education and could support conservation efforts through research. Over a 3-yr period, 12 male striped bass housed in a multispecies exhibit developed coelomic distension. The testes were enlarged (12/12), cystic (2/12), and heterogeneous (3/12) on coelomic ultrasound. Upon coeliotomy, enlarged (12/12), partially (4/12) or totally white discolored (6/12) testes were noted. These were associated with coelomic hemorrhage (8/12), effusion (3/12) or adhesions to surrounding organs (9/12). Orchiectomies were performed in all fish. Among these, seven fish survived 2 mon postsurgery, and four fish were still alive 900 d postsurgery. Germ cell neoplasia was diagnosed on histopathological examination in 9 of 12 individuals, but no abnormalities were found in the three other cases. Preventive orchiectomies were performed on the remaining six male striped bass in this exhibit. Germ cell neoplasms were present in two of these six fish. No anesthetic or surgical complications were noted; all six cases were alive 2 mon postsurgery and four of the fish survived 900 d postsurgery. Survival times were not significantly different between fish that underwent preventive or curative orchiectomy (P = 0.19). Although risk factors associated with the development of these gonadal tumors remain unknown, a genetic or environmental origin is suspected. Orchiectomy should be considered in suspected cases of testicular tumors.

Intracranial embryonal neoplasm in an alpaca.

An 11-y-old hembra alpaca was admitted because of cerebellar and vestibular signs, dysphagia, and aspiration pneumonia; without clinical improvement following empirical therapy, the patient was euthanized. On autopsy, a neoplasm was found incorporating the right vestibulocochlear nerve at the level of the acoustic meatus. Histologically, the mass was composed of a multiphasic primitive cell population associated with a dense fibrous stroma and enveloping a remnant ganglion and nerve bundles. Patterns included dense ribbons and cords of embryonal neuroepithelial cells admixed with loosely defined interlacing spindle cells. The embryonal cells had angular cell profiles with variable amounts of lightly basophilic cytoplasm, ovoid-to-irregular nuclei, and an open chromatin pattern with a typically inapparent nucleolus. Necrosis was not evident, and there was 1 mitotic figure per 2.37 mm2. The entire mass was infiltrated by small numbers of lymphocytes and plasma cells. Immunohistochemistry (IHC) revealed strong and diffuse cytoplasmic immunolabeling for vimentin, microtubule-associated protein-2, protein gene product 9.5, and synaptophysin; ~50% immunolabeling for cytokeratin AE1/3; sporadic OLIG2 and S100 immunolabeling; and absent glial fibrillary acidic protein immunolabeling. Based on the histologic pattern and the IHC results, our diagnosis was a poorly differentiated embryonal tumor with ependymal differentiation associated with the vestibulocochlear nerve.

Embryonal Tumour in the Eye of a Lady Gouldian Finch (Erythrura gouldiae) and Limited Review of Intraocular Tumours in Birds.

Primary intraocular tumours are infrequent in birds. A 2-year-old male Lady Gouldian finch (Erythrura gouldiae) originally presented to the referring veterinarian after the owner noticed mild swelling of the right eye. After the eye had enlarged rapidly and bulged from the orbit, the bird was seen at the referral hospital. Enucleation was attempted but the bird died after sedation. The eye was removed and, on sectioning, a mass was seen primarily in the vitreous chamber with extension through the sclera to the retrobulbar area. After routine histology, immunohistochemistry and electron microscopy, the mass was diagnosed as an embryonal tumour of probable retinal origin. This type of tumour has rarely been documented in birds and we could find no references to any report in Estrildidae.

Ovarian mixed germ-cell tumor comprising mature teratoma and embryonal carcinoma in a four-toed hedgehog (Atelerix albiventris).

This report describes the clinical and histopathological characteristics of a rare mixed germ-cell tumor comprising teratoma and embryonal carcinoma in the left ovary of a 10-month-old four-toed hedgehog, with chief complaints of loss of appetite and lethargy. Laparotomy revealed a swollen left ovary with small disseminated peritoneal nodules, and bilateral ovariohysterectomy was performed. The left ovary had a mature teratoma with well-differentiated fat, bone, cartilage, salivary gland, trachea, keratin cyst, and nervous tissues, and an embryonal carcinoma consisting of poorly-differentiated epithelial cells arranged in tubular, alveolar, or solid patterns. Immunohistochemically, the embryonal carcinoma cells were positive for placental alkaline phosphatase and c-KIT. This is the first case of mature teratoma with embryonal carcinoma in the ovary of a hedgehog.

Metastatic Mixed Germ Cell Tumour with Embryonal Carcinoma and Choriocarcinoma in a Female Eurasian Harvest Mouse (Micromys minutus).

Mixed germ cell tumours occur rarely in veterinary species. This report describes a case of metastatic mixed germ cell tumour in a female Eurasian harvest mouse (Micromys minutus). The tumour was extensive in one ovary and the uterus, and was characterized by two distinct tumour cell populations with features typical of embryonal carcinoma (EC) and choriocarcinoma (CC). Metastases of CC to the lungs and liver were observed. The exact origin of the CC was unclear, but the possibility of a non-gestational CC is favoured, given the context of a mixed germ cell tumour and lack of p53 expression. EC diagnosis was confirmed by immunohistochemical labelling of CD30 and lack of immunoreactivity for c-Kit. In addition, membranous ß-catenin expression was present in the EC component, indicating an inactive Wnt/ß-catenin pathway, which is required for the maintenance of pluripotency.

Extragonadal malignant teratoma in a dog - case report / Teratoma extragonodal maligno em cão - relato de caso

Teratomas are neoplasms thought to arise from germ cells which usually occur within gonads and are rarely described on extragonadal sites. The present study reports a case of a 15 year old female mongrel dog with a lumbosacral tumor. The tumor was microscopically composed of embryonic tissues with areas containing atypical undifferentiated cells, leading to the diagnosis of a malignant teratoma. Malignant teratomas are uncommon tumors in domestic animals.(AU)

Os teratomas são neoplasias originárias das células germinativas que têm como sítio principal as gônadas; raramente ocorrem em sítios extragonodais. O presente estudo relata um caso de uma cadela de 15 anos de idade, sem raça definida, apresentando aumento de volume na região lombossacral que ao exame microscópico revelou neoformação composta por tecidos de origem embrionária, com áreas indiferenciadas exibindo atipia celular, características compatíveis com teratoma maligno. Teratomas malignos são incomuns em animais domésticos.(AU)

Embryonal central nervous system tumor in the brain of a goose.

Embryonal central nervous system (CNS) tumor is a rare malignant neoplasm that arises from the neural crest. Herein we describe an embryonal tumor in the brain of an adult male domestic goose ( Anser anser) that was euthanized after a short history of wandering and lethargy. Grossly, a focal, bright-red, soft plaque was present on the ventral aspect of the brain, extending from the optic chiasm to the midbrain, as well as into the dorsal neuroparenchyma. Histologically, the nodule consisted of a poorly demarcated population of neoplastic cells arranged in streams and bundles, and occasionally palisading around small capillaries (pseudorosettes). Neoplastic cells were elongate and had scant, finely granular, eosinophilic cytoplasm, and elongate nuclei with dense chromatin. Mitoses were uncommon. Scattered foci of intratumoral necrosis and microvascular proliferation were present. Neoplastic cells were immunoreactive for doublecortin and neuronal nuclei. Ultrastructurally, neoplastic cells had elongated-to-polyhedral cytoplasm with short processes, scarce intermediate filaments, and small round mitochondria and rough endoplasmic reticulum. The cell membrane had varied numbers of intercellular anchoring-like junctions, and nuclei were round-to-elongate and had marginal aggregates of heterochromatin. Morphologic, immunohistochemical, and ultrastructural findings in our case are consistent with a poorly differentiated embryonal tumor.

MRI Findings of Suprasellar Germ Cell Tumors in Two Dogs.

A 4 yr old border collie presenting for mydriasis and decreased mentation and a 7 yr old Boston terrier presenting for obtundation, head tilt, and paraparesis were both evaluated using MRI. Findings in both included mass lesions of the thalamus and brainstem that were hypo- to isointense on T1-weighted images and hyperintense on T2-weighted images with regions of hypointensity, and robust contrast enhancement and displacement of adjacent structures. Postmortem histopathology findings, tumor location, and a mixed pattern of epithelial cell differentiation were consistent with germ cell tumor in both cases. Germ cell tumor of the suprasellar region is an infrequently reported neoplasm of dogs and imaging findings in this species have not been well described in the prior literature.

Ovarian Embryonal Carcinoma in a Dog.

A 17-month-old female doberman pinscher was referred for an abdominal mass and ascites. Exploratory laparotomy revealed the presence of a large neoplastic mass replacing the right ovary and associated with multiple mesovarian, mesometrial and peritoneal nodules. An ovariohysterectomy was performed. Grossly, the tumour was soft and multilocular with large areas of haemorrhage and necrosis. Microscopically, it was infiltrative and composed of round and polygonal cells arranged respectively in solid sheets or forming distorted tubular structures separated by thick fibrovascular septae. Tubules contained necrotic debris, proteinaceous fluid or small endoluminal papillary structures. Marked cellular atypia, multiple neoplastic emboli and high mitotic count were observed. Immunohistochemically, the round cells uniformly expressed placental alkaline phosphatase, while the polygonal cells arranged in tubules and papillae expressed cytokeratin (CK) AE1/AE3 and CK7. A final diagnosis of metastasizing ovarian embryonal carcinoma (EC), a primitive germ cell tumour characterized by rudimentary epithelial differentiation was made. Canine ovarian EC should be considered as a differential diagnosis for undifferentiated aggressive ovarian tumours in young dogs.

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.

Immunohistochemical study of mixed germ cell sex cord stromal tumours in 13 canine testes.

Mixed germ cell sex cord stromal tumours (MGSCTs) are composed of seminiferous tubules, filled with admixed neoplastic Sertoli cells (SCs) and germ cells (GCs). The aim of the present study was to describe 13 canine testicular MGSCTs and to investigate the histochemical features and the immunophenotype of the neoplastic GCs and SCs. Neoplastic SCs were always diffusely labelled for vimentin (VIM), neuron specific enolase (NSE), inhibin (INH)-α and anti-Müllerian hormone (AMH). Cytokeratins AE1/AE3 (CK) and desmin (DES) were expressed in 6/13 and 8/13 cases, respectively. Neoplastic GCs were labelled for placental alkaline phosphatase (PLAP) in 7/13 cases and for CD117 (KIT) in 8/13 cases, while 10 cases were stained uniformly by periodic acid-Schiff (PAS). Immature canine SCs are known to express CK, DES, INH-α and AMH, while immature GCs are stained by PAS and express PLAP and KIT. This GC phenotype also distinguishes between classical and spermatocytic seminoma, with the latter being negative for these markers. The results of the present study show that both neoplastic SCs and GCs in MGSCTs have a de-differentiated phenotype.

Immunohistological Description of Nongestational Ovarian Choriocarcinoma in Two Female Mice With Conditional Loss of Trp53 Driven by the Tie2 Promoter.

Nongestational ovarian choriocarcinoma (NGCO) is a tumor of germ cell origin seldom described in nonhuman species. Few spontaneous cases are reported in macaques and mice, with the B6C3F1 strain overrepresented. This report describes 2 cases of ovarian choriocarcinoma in nulliparous female mice with conditional loss of Trp53 under the Tie2 promoter. The mouse line was maintained on a mixed genetic background including Crl: CD1(ICR) and 129X1/SvJ strains. In both cases, affected ovary was partially replaced by blood-filled lacunae lined by neoplastic trophoblast-like giant cells. Immunohistochemically, neoplastic cells expressed folate-binding protein and prolactin and were invariably negative for p53. To the authors' knowledge, this is the first report characterizing this entity in a genetically engineered mouse (GEM) line. Considering that germ cells (the cell population from which NGCO originates) constitutively express Tie2 receptor, it can be speculated that Tie2-driven deletion of Trp53 may have played a role in the development of these tumors.

Equine placental mixed germ cell tumor with metastasis to the foal.

The placenta from an embryo transfer-recipient mare and live foal was examined. The placenta was effaced by multifocal masses, which ranged from less than 1 cm to 14 cm in diameter. The foal represented at 52 days for lethargy, ataxia, and urine dribbling; due to a poor prognosis, the foal was euthanized. At necropsy, the liver was effaced by multifocal, pale, irregular nodules. The lumbar vertebrae and other skeletal sites had multifocal lytic lesions. The placenta had 4 populations of neoplastic cells, including a spindle cell population, tall columnar and transitional epithelial cell populations, and an undifferentiated polygonal cell population. The foal's liver had similar populations and patterns of cells as those in the placenta. The lesion in the placenta and the masses in the foal were diagnosed as a mixed germ cell tumor and metastatic mixed germ cell tumor, respectively.

Testicular yolk sac tumor of myxomatous, reticular, and polyvesicular vitelline type in a newborn calf.

Yolk sac tumors (YSTs) are rare neoplasms of germ cell origin. In humans, the tumors primarily occur in the testes or ovaries, but occasionally develop at other sites. The neoplastic cells of YSTs form many histological patterns resembling embryonal structures, and the World Health Organization classification lists 11 such patterns: reticular, macrocystic, endodermal sinus, papillary, solid, glandular-alveolar, myxomatous, sarcomatoid, polyvesicular vitelline, hepatoid, and parietal. Among domestic animals, only 2 cases of YST, which were of testicular and abdominal cavity origin, have been reported in calves. In both cases, neoplastic cells had epithelial properties and disseminated metastases in the abdomen. In the present study, the enlarged testis of a newborn calf, which was subsequently diagnosed as YST and exhibited myxomatous, reticular, and polyvesicular vitelline histological patterns, is described. There was no metastasis in this case, and histological and immunohistochemical features varied from previous cases of YST.

Ovarian mixed germ cell tumor with yolk sac and teratomatous components in a dog.

Mixed germ cell tumors of the ovary have rarely been reported in veterinary species. A 3-year-old intact female Labrador Retriever dog was presented for lethargy, abdominal distention, and a midabdominal mass. An exploratory laparotomy revealed a large (23 cm in diameter) left ovarian tumor and multiple small (2-3 cm in diameter) pale tan masses on the peritoneum and abdominal surface of the diaphragm. Histological examination of the left ovary revealed a mixed germ cell tumor with a yolk sac component with rare Schiller-Duval bodies and a teratomatous component comprised primarily of neural differentiation. The abdominal metastases were solely comprised of the yolk sac component. The yolk sac component was diffusely immunopositive for cytokeratin with scattered cells reactive for α-fetoprotein and placental alkaline phosphatase. Within the teratomatous component, the neuropil was diffusely immunopositive for S100, neuron-specific enolase, and neurofilaments with a few glial fibrillary acidic protein immunopositive cells. Ovarian germ cell tumors may be pure and consist of only 1 germ cell element or may be mixed and include more than 1 germ cell element, such as teratoma and yolk sac tumor.

Spontaneous nonmetastatic choriocarcinoma, yolk sac carcinoma, embryonal carcinoma, and teratoma in the testes of a swiss albino mouse.

A 12-week-old Swiss Albino mouse was presented with unilateral (left) testicular enlargement of approximately 1.5 cm in diameter and the right testicle mildly reduced in size and weight. Histopathology evaluation revealed three distinct neoplasms in the left testicle: choriocarcinoma, yolk sac carcinoma, and embryonal carcinoma. Teratoma was diagnosed in the right testicle. The histomorphological and immunohistochemical characteristics of the tumor are presented here. To the best of the authors' knowledge, this is the first report of spontaneous nonmetastasizing choriocarcinoma, yolk sac carcinoma, embryonal carcinoma, and teratoma in testes of a Swiss albino mouse.

A suprasellar germ cell tumor in a 16-month-old Wagyu heifer calf.

A 16-month-old Wagyu heifer calf presented for depression, inappetence, and polyuria/polydipsia. Physical examination revealed that the heifer calf was mentally dull, subjectively small for her age, bradycardic, and hypothermic and had bilateral nasal discharge. Laboratory tests revealed marked serum and cerebrospinal fluid hypernatremia and hyperchloremia with increased cerebrospinal fluid protein. The heifer calf was treated with Ringer solution intravenously for dehydration and electrolyte abnormalities, and with 1 dose each of thiamine and penicillin. Clinical deterioration prompted the owner to elect humane euthanasia. Necropsy revealed a mass lesion in the suprasellar region. Histopathology was consistent with a suprasellar germ cell tumor; the mass stained positive on immunohistochemistry for cytokeratin, vimentin, and c-kit. Suprasellar germ cell tumors have previously been reported in human beings and dogs.

Embryonal carcinoma in the abdominal cavity of a male calf.

An embryonal carcinoma was diagnosed in the abdominal cavity of a 55-day-old male calf. Macroscopically, a large volume of ascitic fluid was observed along with white to yellowish-white masses of various sizes densely located on the abdominal wall and the surface of abdominal organs. There was an absence of testes in the scrotum. Histologically, the tumor cells were polygonal, and the tumor was mostly composed of sheets of densely packed solid patterns with occasional papillary and tubular structures. Cell nuclei were variable in size, and cellular mitotic rate was high. Immunohistochemically, tumor cells were positive for alpha-fetoprotein, placental alkaline phosphatase, cytokeratin, and carcinoembryonic antigen. Ultrastructurally, the tumor cells had large nuclei, extensive rough endoplasmic reticulum, and small numbers of mitochondria. Microvillus-like structures and desmosomes were occasionally observed. From lectin histochemical examination, the tumor cells were positive for concanavalin A, wheat germ agglutinin, peanut agglutinin, Dolichos biflorus agglutinin, soybean agglutinin, Griffonia simplicifolia I, and Bauhinia purpurea, and negative for Ulex europaeus agglutinin I. Results of histopathological, immunohistochemical, and ultrastructural examinations of the tumor were similar to those obtained for human embryonal carcinoma.

Testicular germ cell tumours in dogs are predominantly of spermatocytic seminoma type and are frequently associated with somatic cell tumours.

Unlike seminomas in humans, seminomas in animals are not typically sub-classified as classical or spermatocytic types. To compare testicular germ cell tumours (TGCT) in dogs with those of men, archived tissues from 347 cases of canine testicular tumours were morphologically evaluated and characterized using human classification criteria. Histopathological and immunohistological analysis of PLAP, KIT, DAZ and DMRT1 expression revealed that canine seminomas closely resemble human spermatocytic seminomas. In addition, a relatively frequent concomitant presence of somatic cell tumours was noted in canine TGCT. None of the canine TGCT evaluated demonstrated the presence of carcinoma in situ cells, a standard feature of human classical seminomas, suggesting that classical seminomas either do not occur in dogs or are rare in occurrence. Canine spermatocytic seminomas may provide a useful model for this rare human neoplasm.

Neuronal embryonal tumors in fish.

This article describes 11 cases of neuronal embryonal neoplasia in captive adult teleost fish. Neoplasms were located within 1 or both eyes of 8 fish and the skin of 3 other fish. Ocular neoplasms most often presented as unilateral or bilateral exophthalmia. Seven ocular and 1 cutaneous mass were composed of small triangular (carrot-shaped) neoplastic cells with Flexner-Wintersteiner-type rosette formation. Mass location and histologic and ultrastructural features were suggestive of retinoblastomas. One ocular mass was composed of ribbons and rosettes of neoplastic cells with multiple areas of neuronal differentiation and was diagnosed as a teratoid medulloepithelioma. A cutaneous mass from an electric eel (Electrophorus electricus) consisted of rosettes and streams of elongate neoplastic cells. The epidermal electroreceptor (ampullary) organ was considered as an origin. Although distant metastases were not observed, neoplasms were generally locally aggressive with postexcision recurrence. There was occasional spread to or de novo occurrence within the contralateral eye.