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A 5-year-old intact male mixed-breed cat weighing 4.5 kg was referred to our hospital with a left testicular mass. CT revealed mild heterogeneous contrast enhancement and calcification in the testicular mass. A well-defined, contrast-enhancing, multiloculated mass with fluid-filled areas was extended from the testicular mass in the scrotum to the caudal aspect of the left kidney. The abdominal mass extended to the right crus of the diaphragm, and the gastrointestinal tract was compressed dorsally. Histopathology was consistent with teratoma. Characteristic CT findings in a feline testicular teratoma may include calcification and cystic areas., (© 2024 The Authors. Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

A Swiss mountain dog, ~3 y old, was brought to a veterinary clinic because of a progressive enlargement of the abdomen. Upon clinical examination, a large mass was detected. After surgical extraction, the mass was confirmed to be a large ovarian teratoma. The weight of the tumor was > 16% of the dog's overall body weight. The dog recovered fully after surgery. The observations from this case suggest that, although teratomas are rare, prompt and accurate diagnosis is necessary to prevent further growth of these masses and to ensure positive outcomes., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Teratoma is a rare tumour in fish consisting of tissues from more than one germ layer, that may be located in either the gonads or extragonadal sites. Teratomas in many fish species remain poorly understood. In this work, we performed the first histological examinations of extragonadal teratomas in Poecilia wingei and also examined the influence of a large teratoma on male sexual activity. The studied teratomas shared general organizational features, but they also had variations in both external and internal features. In teratomas, the most common and highly differentiated tissues were striated muscle and nervous tissue. Despite the tumour, the male P. wingei exhibited normal mating behaviour and retained the ability for successful copulation. The structural features of extragonadal teratomas in guppy fish indicate a possible connection between these tumours and a failure of conserved processes operating in the embryonic germline., (© 2024 John Wiley & Sons Ltd.)

A 2-year-old, intact female, Labrador Retriever was referred for progressive abdominal distension, assessed by emergency clinicians as being extrauterine in origin on AFAST. Abdominal radiographs and ultrasound identified a large, lobulated, partially mineralized, soft tissue, mid-abdominal mass and gravid uterus. Contrast-enhanced CT identified a mixed fat to soft tissue attenuating mass with a complex internal mineralized matrix, heterogeneous contrast enhancement, receiving blood from the left ovarian artery. Histology confirmed a left ovarian teratoma, diffuse endometrial hyperplasia, and fetal implantation. The patient had a good post-operative outcome for 2 years, but was later diagnosed with primary cranial mediastinal neuroendocrine carcinoma., (© 2023 The Authors. Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

A retrospective study was carried out to investigate incidence, clinical signs and ultrasonographic findings of ovarian tumours in a population of dogs referred to the Veterinary Teaching Hospital of the University of Perugia (Italy) and Anicura Tyrus Veterinary Clinic (Terni, Italy). The period of study ranged from January 2005 to December 2021. A total of 1910 dogs were affected by neoplasia but only 35 of them (1.8%), of different breeds and ages, were found to have ovarian tumours. Ultrasound of the ovaries was performed based on clinical signs; the diagnosis was achieved after ultrasound findings prompted ovariohysterectomy and ovarian pathologic evaluation In our study, the age of bitches affected by ovarian neoplasia ranged from 3 to 20 years (mean 9.6 ± 3.8). The histopathological findings of ovarian masses identified 16 granulosa cell tumours (GCT) (46%), 7 adenomas (20%), 5 adenocarcinomas (14%), 2 teratomas (6%), 1 leiomyoma (3%), 1 luteoma (3%), 1 tecoma (3%), 1 dysgerminoma (3%), and 1 haemangiosarcoma (3%). In particular, with respect to clinical signs, 69% of bitches showed abnormalities of estrus cycle (short interestral interval, persistent estrus, prolonged interestral interval). The other main clinical signs included abdominal distention, palpable abdominal mass, vulvovaginal discharge, polyuria/polydipsia, mammary masses. When present, the laboratory abnormalities were slight anemia and leucocytosis with neutrophilia. The tumours were ultrasonographically classified as mainly solid: 12/35 (34%) (1 adenoma, 4 adenocarcinomas, 1 dysgerminoma, 1 haemangiosarcoma, 1 leyomioma, 1 luteoma, 1 GCT, 1 tecoma, 1 teratoma); solid with cystic component 13/35 (37%) (9 GCT, 2 Adenomas, 1 adenocarcinoma, 1 teratoma); and mainly cystic 10/35 (29%) (6 GCTs, 4 adenomas). In our study, the ultrasound examination allowed us to suspect ovarian neoplasia in asymptomatic subjects referred for breeding management or for preventive health check. On the basis of our data, we proposed to perform a complete periodic examination of the reproductive system once a year from 6 years. Nevertheless, the presence of ovarian neoplasms found in young subjects, during breeding management, suggest including routine ultrasound examination of the reproductive tract., Competing Interests: Declaration of conflicting interest The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2023. Published by Elsevier Inc.)

A 2-month-old female mixed cat was emaciated due to dysphagia, and inspection of the mouth revealed a 2 cm pedunculated mass elongated from the palate, which occupied the oral cavity. The mass was surgically removed, and histopathological examination revealed that the tumor was composed of three germ cell layers: ectodermal (skin and skin appendages), mesodermal (cartilaginous and osseous structures), and endodermal (glandular and respiratory mucosa) tissues. An immature teratoma was diagnosed because of the presence of immature neuroectodermal tissues, and the presence of nephroblastic components was a characteristic finding in this case. This is the first report of an oropharyngeal teratoma in cats and the first case of an immature teratoma with nephroblastic components in a domestic species.

A 26-year-old, male eclectus parrot ( Eclectus roratus ) was presented to its primary care veterinarian for a 10-day history of increased respiratory effort, lethargy, and a single episode of regurgitation. Hepatomegaly, proventricular enlargement, cranial displacement of the ventriculus, and coelomic effusion were suspected based on a 1-view radiographic image, and the patient was referred for further evaluation. On presentation to the referral veterinary hospital, a distended coelom and dyspnea with abnormal respiratory sounds were abnormalities noted upon physical examination of the patient. The bird was hospitalized for supportive care, and diagnostic tests were performed. Initial radiographic images at the referral hospital revealed a large intracoelomic mass. A computed tomographic scan was performed; however, the origin of the mass could not be determined. A fine-needle aspirate and cytologic evaluation of the intracoelomic mass revealed a neoplastic process but no specific tissue type. Two days after presentation to the referral hospital, an exploratory coeliotomy to surgically resect the mass was attempted. The mass occupied most of the coelomic cavity, with multiple adhesions to internal organs. The mass was successfully resected; however, the patient destabilized and died despite resuscitation efforts. Histopathologic examination of submitted tissue from the mass with immunohistochemistry revealed mixed populations of neoplastic cells differentiated from 3 primordial germinal layers, confirming the diagnosis of teratoma. Teratomas appear to be a rare tumor in avian species but should be included in a list of differential disease diagnoses for abnormal tissue masses of unknown origin. Only 2 cases of teratomas have, to our knowledge, been reported in psittacine species.

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.

Background: Teratomas are germ cell neoplasms composed of a wide variety of tissues. In the woodchuck, only one testicular teratoma has been described in the literature. The objective of this report was to describe the radiologic and pathologic findings in a female woodchuck (Marmota monax) with an ovarian teratoma consisting of mature tissues originating from all three germ layers., Case Presentation: A 2-year-old female woodchuck that had been infected at birth with woodchuck hepatitis virus and subsequently developed hepatocellular carcinoma was incidentally discovered to have a mobile 6.6 × 4.8 × 4.7 cm abdominal mass on computed tomography (CT) imaging. The tumor was predominantly solid and heterogenous on CT with soft tissue, fat, and areas of dense calcification. The teratoma did not enhance with intravenous contrast administration. On ultrasound, the tumor was solid with heterogeneous echogenicity, reflecting the fat content and areas of calcification. Sonolucent areas were present that may have represented cysts. There was heterogeneously increased signal on T1-weighted magnetic resonance imaging (MRI) and heterogeneous hyperintensity in T2-weighted imaging. Fat was evident within the tumor. At necropsy, the tumor was attached to the distal end of the right uterine horn. Histopathology showed mature tissue types representing all three germ layers., Conclusions: Ovarian teratoma should be considered in the differential diagnosis of ovarian or abdominal masses in woodchucks. The tumor displayed mature tissue derived from all three germ layers. CT, ultrasound, and MRI findings were presented in detail and matched the typical imaging appearance of teratomas.

A 7-month-old male domestic ferret (Mustela putorius furo) was presented for evaluation of unilateral testicular enlargement. Microscopic examination of the left testicle revealed a neoplasm with differentiation along multiple cell lines (ectoderm, endoderm, mesoderm) including respiratory epithelium, bone and haired skin. A poorly differentiated epithelial component was dispersed throughout the neoplasm with invasion of testicular lymphatics. The animal developed progressive dysuria and was euthanized. At necropsy, metastasis of the poorly differentiated epithelial component was present in the urinary bladder, ureters, prostate gland, pelvic fat, abdominal and thoracic lymph nodes, kidney and lung. This is the first report of a malignant testicular teratoma with widespread metastasis in this species., (Published by Elsevier Ltd.)

A 3-year-old Quarter Horse mare presented with an approximate 1-month history of progressive weight loss, anorexia and lethargy that abruptly worsened 48 h before death. Post-mortem examination revealed free flocculent fluid and a large mass within the ventral abdomen that dorsally displaced the caecum and large intestine. An ovarian teratocarcinoma with metastasis to regional lymph nodes was diagnosed histologically. Although benign teratomas are the second most common ovarian neoplasm in equids, reports of malignant teratomas in horses are rare. This report documents an unusual presentation of a rarely reported malignant neoplasm of the reproductive tract in horses., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Ovarian teratomas are occasionally reported in dogs; the rarest type is the monophasic teratoma, composed of tissues originating from only one germ layer. Canine endometrial adenocarcinomas are also rare in dogs and mainly affect geriatric females. This report describes the case of co-existing ovarian teratoma and uterine adenocarcinoma in a 10-year-old nulliparous female Boxer presented with lethargy, anorexia and purulent vaginal discharge. Abdominal ultrasonography evidenced pyometra and a mass in the left ovary. This was composed of a uniform whitish tissue with multiple cystic structures. The histology revealed an atrophy of the ovarian parenchyma, compressed by a proliferation of well-differentiated nervous tissue staining positively to vimentin, S100 and neuronal specific enolase (NSE), and negatively to keratin and inhibin. The left uterine horn, whose diameter was markedly increased, showed foci of endometrial cellular atypia, evident nucleoli and mitoses, at light microscopy. To our best knowledge, this is the first report of a co-existing ovarian monophasic teratoma and endometrial adenocarcinoma, two rare reproductive neoplasia in dogs., (© 2019 Blackwell Verlag GmbH.)

A 5-y-old backyard Araucana-Americana rooster was presented to the regional diagnostic laboratory with a history of progressive lethargy and respiratory signs. Autopsy revealed a single large mass of testicular origin in the coelomic cavity, causing compression of other organs. Histologically, the mass was 1 neoplasm with mixed components of 2 different germ cell tumors, namely a teratoma composed of elements of all 3 primordial germ cell lines (ectoderm, mesoderm, and endoderm), and a seminoma consisting of round or polygonal cells arranged in sheets supported by a scant fibrovascular stroma. Teratomas and seminomas are both considered to be uncommon neoplasms in poultry medicine. A testicular teratoma is composed of mature embryonic tissue derived from at least 2 of the 3 germinal layers. Seminomas and teratomas both arise from the germinal epithelium of seminiferous tubules and are classified as germ cell tumors. This neoplastic mass thus is a rare case of a mixed germ cell tumor.

An approximately 42-year-old, wild-caught, red-crowned Amazon parrot ( Amazona viridigenalis ) was evaluated for a subcutaneous mass to the right of the keel. Cytologic examination of a fine needle aspirate of the mass were suggestive of granulomatous inflammation. The mass was surgically excised, and the parrot was treated with oral nonsteroidal anti-inflammatory drugs. Histologically, the mass was diagnosed as a teratoma with stratified squamous epithelial and neuroectodermal components. Tumor cells extended to surgical margins. Two years later, the neoplasm recurred, with regrowth of only the neuroectodermal component. The neoplasm was again removed surgically, but it recurred again 14 months later, necessitating a third surgery. Histopathologic examination confirmed recurrence of the original neoplasm in both instances, with incomplete margins on both excisions., (© 2019 by the Association of Avian Veterinarians.)

The biological behavior of teratomas depends on several interdependent clinical and epidemiological variables such as age at diagnosis, sex, tumor microenvironment, and tumor morphology, among others. All these variables are correlated to different cytogenetic and molecular aberrations (Harms et al., 2006). There are null reports of teratomas in pigs. The aim of this study was to characterize the tissues present in a mature congenital intraneural teratoma in the cerebellum area of a Landrace female pig of 6-7 weeks old. In this study, tissue control samples were used to validate each staining method. Sections from the teratoma showed normal histology of the cerebellum, including rounded Purkinje neurons with abundant cytoplasm, euchromatic nuclei, and prominent nucleoli; glial cells with a scarce amount of cytoplasm and small and highly basophile-nuclei (compact chromatin) and axonal tracts (white matter). Interestingly, we also observed areas with tissues different from the nervous tissue, including bundles of well-defined skeletal muscle fibers with a striated pattern and peripheral nuclei; hyaline cartilage plaques, with prominent presence of chondrocytes in their lagoons forming isogenous groups surrounded by a territorial and interterritorial matrix; trabeculated bone tissue; and adipocytes, which are ring-shaped cells with peripheral flattened nuclei, as a result of the presence of a central large lipid droplet. To our knowledge, this study is the first to describe a congenital intraneural mature teratoma in the cerebellum of a pig.

Background: Articular cartilage lacks a regenerative response. Embryonic stem cells (ESCs) are a source of pluripotent cells for cartilage regeneration. Their use, however, is associated with a risk of teratoma development, which depends on multiple factors including the number of engrafted cells and their degree of histocompatibility with recipients, the immunosuppression of the host and the site of transplantation. Colonies of sheep embryonic stem-like (ES-like) cells from in vitro-produced embryos, positive for stage-specific embryonic antigens (SSEAs), alkaline phosphatase (ALP), Oct 4, Nanog, Sox 2 and Stat 3 gene expression, and forming embryoid bodies, were pooled in groups of two-three, embedded in fibrin glue and engrafted into osteochondral defects in the left medial femoral condyles of 3 allogeneic ewes (ES). Empty defects (ED) and defects filled with cell-free glue (G) in the condyles of the controlateral stifle joint served as controls. After euthanasia at 4 years post-engraftment, the regenerated tissue was evaluated by macroscopic, histological and immunohistochemical (collagen type II) examinations and fluorescent in situ hybridization (FISH) assay to prove the ES-like cells origin of the regenerated tissue., Results: No teratoma occurred in any of the ES samples. No statistically significant macroscopic or histological differences were observed among the 3 treatment groups. FISH was positive in all the 3 ES samples., Conclusions: This in vivo preclinical study allowed a long-term evaluation of the occurrence of teratoma in non-immunosuppressed allogeneic adult sheep engrafted with allogeneic ES-like cells, supporting the safe and reliable application of ES cells in the clinic.

A 15 months-old Simmental heifer (SH) and a 18 months-old Marchigiana heifer (MH) were referred to the Faculty of Veterinary Medicine of Teramo (Italy). In the rst heifer, clinical examination of the vulva, vestibulum, and vagina showed no signs of disease and no discharge was detected. Palpation per rectum revealed a mass in the left portion of the abdominal cavity, closely attached to the tip of the left uterine horn. The mass was mainly rm and brous and its surface was slightly lobulated. The second heifer had a history of a regular cycle from the 11th to the 14th month of age followed by an anoestrus state. Gynecological examination revealed the presence of a large and rm mass in the caudal left region of the abdomen, soon over the edge of the pelvis oor. In both cases, the histologica examination of the mass revealed an immature ovarian teratoma.

A 2-mo-old, female blue-and-yellow macaw (Ara ararauna) presented with severe abdominal distension, pain, and respiratory distress. Ultrasonographic examination detected a heterogeneous mass with multiple anechoic areas, compatible with a multilocular cyst, occupying most of the coelomic cavity. Postmortem examination revealed a mass of 12.0 × 8.5 × 5.0 cm, which had an irregular surface and was connected by a pedicle to the ileum. This mass compressed and displaced the liver, proventriculus, gizzard, and intestines cranially to the left. The cut surface was lobulated, gray-white, mildly firm or soft, and was interspersed with multiple cysts filled with viscous and opaque liquid. Microscopically, it was composed of well- differentiated embryonic tissues from the endoderm, mesoderm, and ectoderm; therefore, it was diagnosed as a mature teratoma, which was theorized to have originated from Meckel's diverticulum. This study is the first, to the authors' knowledge to report a case of a teratoma in a blue-and-yellow macaw.

A young adult, female, free-ranging Japanese raccoon dog ( Nyctereutes procyonoides viverrinus) with scabies infection was found dead as a result of traumatic injuries presumed to reflect vehicular trauma. Necropsy showed a large solid mass located on the left ovarian region, occupying a third of the abdominal cavity. Histologically, the mass contained complex tissues derived from three germinal layers, with areas of cuboidal or columnar epithelium, keratinized squamous epithelium, bone, cartilage, and adipose tissue. This paper presents the first morphologic description of ovarian teratoma in a raccoon dog.

A 5-year-old female domestic shorthair cat was presented with abdominal distension and serum biochemical evaluation indicated a high concentration of oestradiol (32.81 pg/ml). Exploratory laparotomy revealed a large cystic mass in the right ovary with cystic fluid containing a high level of oestradiol (18.80 pg/ml). The tumour was composed of immature neuroectodermal tissue, mature cartilage, smooth muscle, adipose tissue and aggregated, poorly differentiated mesenchymal cells. It contained cysts of various sizes that were lined by epithelium of different types. The basal layer of the lining epithelium was shown to express aromatase by immunohistochemistry. The findings suggest that this was a novel, malignant, oestrogen-secreting teratoma and that the aromatase-positive, neoplastic cells may have been the source of elevated levels of serum oestrogen., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Ovarian tumors in reptiles are uncommonly reported in the literature and for green iguanas previously reported cases include teratomas, one adenocarcinoma and one papillary cystadenocarcinoma. The present report is the first of a malignant ovarian teratoma in a green iguana. Complete and detailed pathological features, differential diagnosis and surgical management of malignant ovarian teratoma are discussed in this paper., Case Presentation: A 9-year-old intact female green iguana (Iguana iguana) with a clinical history of persistent anorexia and progressive abdominal distension was referred to the surgery department. On physical examination, a presumptive diagnosis of follicular stasis was established. Radiographic evaluation showed a large radioopaque mass within the abdomen, which was visible both in latero-lateral and ventro-dorsal exposures. Abdominal ultrasonography showed a large intra-abdominal mass, with numerous cyst-like structures filled with liquid and a heterogeneous aspect with hypoechoic areas. Exploratory laparatomy was thus suggested and the mass was removed surgically. The histologic findings of the neoplasm were consistent with those of ovarian malignant teratoma. Surgical excision of the mass in our case was considered curative and after a follow-up period of 6 months the animal has recovered completely., Conclusions: A malignant ovarian teratoma has not been previously reported in green iguana and should be included in the list of differential diagnosis of ovarian tumors in this species. This report will contribute to a better understanding of the pathology of this rare tumor in green iguanas.

We describe a congenital mature intracranial teratoma in a Pampas deer ( Ozotoceros bezoarticus ) in southern Brazil. We found an irregular, spongy, space-occupying mass in the brain. The tumor consisted of well-differentiated tissues that derived from all three germ layers.

Scant information is available on the ultrasonographic appearance of different testicular tumours in the stallion. Preoperative ultrasound imaging and gross and microscopic features of a testicular teratoma in a horse is described. An asymptomatic 4 years old cryptorchid Arabian horse was admitted for orchiectomy. Combined transabdominal and inguinal ultrasound examination revealed a large complex ovoid mass, containing both solid and cystic elements with internal echoes, located dorsally to the superficial inguinal ring. Two main hypoechoic cavities divided by a linear hyperechoic septum were evident, with a hyperechoic circular structure inside the lumen of the largest one. A tumour of the undescended testis was suspected. Ultrasound findings guided a provisional diagnosis of teratoma that was confirmed by histology following surgical removal of the tumour. Due to the correspondence between ultrasonographic and morphological features, trans-abdominal ultrasonography was conclusive in the preoperative planning.

A large abdominal mass was identified during an elective preventative health examination in a 25-yr-old female hybrid orangutan (Pongo pygmaeus). Sonographically, the mass was fluid-filled and a presumptive diagnosis of a dermoid cyst or cystic teratoma of an ovary was made. Exploratory laparotomy, after assembly of a surgical team, confirmed that the 2.5-kg cystic mass was associated with the left ovary. Following ovariectomy, perioperative dissection of the mass revealed hair components, confirming the working diagnosis. Because the right ovary was slightly nodular and firmer than expected, and these germ cell tumors sometimes occur bilaterally, excision of the contralateral ovary was elected. Histopathology confirmed the left ovarian mass was a dermoid cyst; the right ovary contained a corpus hemorrhagicum but no evidence of neoplasia. Recovery was uneventful and the orangutan was prescribed hormone replacement therapy to mitigate potential problems associated with a chronic lack of estrogen and progesterone. This case report demonstrates the importance of elective examinations under anesthesia, even in well-trained great apes.

The original tumor, 4 cm in diameter, was found in the left testis of a 2-month old SD rat. The tumor consisted of well-differentiated, mature tissues such as bone, cartilage, adipose tissue, smooth and skeletal muscles, skin, hair, glands (salivary, sebaceous, apocrine and pancreatic exocrine glands) and trachea, as well as nerve tissues. The tumor was diagnosed as a mature type of teratoma, a rare in rat testis. Cloned cell lines (named TSD-B4S and TSD-F9R) were established from the tumor; cellular properties of these cell lines were similar to each other; basically, their cultured cells exhibited vimentin-positive mesenchymal nature with occasional cells reacting to α-smooth muscle actin, glial fibrillary acidic protein and CD163 (a macrophage marker). The cell lines showed tumorigenicity when inoculated into nude mice, being composed of immature mesenchymal cells arranged mainly in a sheet. In TSD-B4S cells treated with differentiation factors, we demonstrated mesenchymal differentiations towards adipogenic, osteogenic and myofibrogenic cells. The cell line (TSD-B4S) would become a useful tool for studies on stem cell differentiation, because the teratoma arises from primordial germ cells like embryonic stem cells.

Congenital teratomas arising in the coccygeal region have not been reported in domestic animals. This report describes a congenital coccygeal teratoma in a male Burmese cat. A round to oval expansile mass with solid and cystic areas was found ventral to the 5th to 7th caudal vertebrae. Microscopically, the tumour was composed of derivatives of all three primordial germ layers with neuroectodermal predominance. Immunohistochemical double labelling identified immature tissue components in combination with Sox2, a regulator of stem cell proliferation and differentiation. Few Sox2-positive cells co-expressed the neural crest stem cell markers vimentin and neurotrophin receptor p75(NTR). Not all Sox2- and p75(NTR)-positive cells expressed vimentin. An overlapping expression of vimentin-negative and Sox2-, p75(NTR)-positive cells and GFAP- and p75(NTR)-positive cells may indicate a transition stage from immature to mature non-myelinating Schwann cells. Periaxin-positive myelinating Schwann cells surrounding neurofilament-positive axons were observed. Sox2 was additionally expressed in immature odontogenic epithelial cells and in immature cells of endodermal origin. Sox2 was not observed in mature cells, with the exception of satellite glial cells and mucous glands. Despite the presence of immature tissue components, no recurrence was observed 1 year after surgical removal., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A 2.75-yr-old female American black bear (Ursus americanus) was found emaciated and unable to rise. It was euthanized due to the perceived poor prognosis. An approximately 18 x 8 x 10-cm, multiloculated, well-demarcated mass that extended from the bifurcation of the trachea, laterally displacing the lung lobes and caudally displacing the heart. The mass contained fibrous connective tissue, cartilage, bone, nervous tissue, smooth muscle, and a variety of epithelial structures. A mediastinal teratoma was diagnosed based on the microscopic features of the neoplasm.

A 10-month-old intact male cat with a clinical history of a large mass in the left perineal region was submitted to the surgery department. The mass had reportedly been present as a small swelling after birth. Cytological evaluation using a fine-needle aspirate showed eosinophilic keratinaceous debris, and was not convincing for the definitive diagnosis. Complete surgical excision was performed. Postoperative function and aesthetics were excellent. Based on gross and histological features the definitive diagnosis of the tumor was mature teratoma with ectodermal and endodermal components. After a follow-up period of 4 months, no signs of recurrence were evident. Surgical excision of the teratoma in our case was considered curative. A perineal location has not been previously reported in the cat and should be considered a rare condition in this species.

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.

An exploratory laparotomy on a mixed-breed bitch of an estimated age of 5 years revealed that she had undergone ovariectomy in the past, but a cystic structure was present in the area of the right ovary and a whitish mass, approximately 3 cm in diameter, in the area of the left ovary. These structures were removed together with an apparently normal uterus. Histological examination of the cyst showed a thin layer of connective tissue, while the left ovarian mass revealed ovarian tissue and highly differentiated nervous tissue, confirmed through immunohistochemistry. A presumptive diagnosis of mature ovarian teratoma was made. Although teratomas generally contain recognizable elements from more than one of the three germ cell layers, they can also be monophasic, when there is only one germ layer component. Ovarian teratomas are rare in the dog and never before have been reported in an ovarian fragment., (© 2012 Blackwell Verlag GmbH.)

Neuroectodermal tumours in man, including medulloblastoma, medulloepithelioma, neuroblastoma, esthesioneuroblastoma, primitive neuroectodermal tumour and dysembryoplastic neuroepithelial tumour, typically occur in children and young adults. These tumour types are occasionally observed in juvenile and adult zebrafish (Danio rerio) either as induced tumours in carcinogen-exposed zebrafish or as an incidental finding in zebrafish≥2years of age. An adult zebrafish submitted for routine histological examination was sent for a second opinion consultation after an uncharacteristic brain mass was identified. Microscopically, the expansile and infiltrative extracortical mass arising from the cerebellum had a diffuse microcystic pattern with solid hypercellular regions occupying 80% of the extrameningeal space and effacing the endomeninx and significantly displacing the metencephalon. The mass was composed of dense sheets of oligodendrocyte-like cells, random neurons and pseudocysts containing 'floating neurons' within a scant mucinous matrix. Neoplastic cells demonstrated positive perinuclear and intracytoplasmic expression of S-100. Malignant dysembryoplastic neuroepithelial tumour was diagnosed based on the histological features of the brain mass, which were indistinguishable from the human tumour. To our knowledge, this is the first report of a dysembryoplastic neuroepithelial tumour in a zebrafish., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A 16-year-old primiparous mare aborted an apparently normal fetus at 240 days of gestation. A large, oval mass, measuring approximately 20 cm × 30 cm × 20 cm, was detected attached to the umbilical cord of the fetus. On the cut surface, the mass showed multifocal cystic structures, foci of mineralization, and diffuse hemorrhages. Histological examination of the mass revealed haphazardly arranged cartilage, bone, mesenchymal stroma, adipose tissue, vascular structures, smooth muscle, ciliated epithelium, squamous cornifying epithelium, and undifferentiated germ cells with areas of necrosis and mineralization. The mass was diagnosed as an umbilical cord teratoma, which is an extremely rare tumor in human beings and, to the authors' knowledge, has only described in the veterinary literature on one occasion.

This report describes the simultaneous occurrence of an ovarian teratoma and a granulosa cell tumor (GCT) with intra-abdominal metastasis in a 1.5 yr old female Doberman pinscher. At surgery, a 20 cm, smooth, intact mass associated with the left ovary and multiple 1-2 cm irregular masses in the broad ligament were found. The masses were surgically removed and submitted for histopathology. A histologic diagnosis of a teratoma and a GCT with broad ligament metastasis was made. Further treatment was elected by the owner and included two cycles of carboplatin therapy. The dog was euthanized 6 wk postoperatively for signs related to metastasis and dyspnea. Teratoma of the ovary, although it contains derivatives of all three embryonic germ cell layers, rarely presents together with either ovarian epithelial or sex cord-stromal tumors. To the authors' knowledge, this is the first reported case of an ovarian teratoma coexisting with a primary GCT with intra-abdominal metastasis in the same ovary in a dog.

A female domestic duck (Anas platyrhynchos domesticus) suddenly died with abdominal distension and a large multilobulated mass within the coelomic cavity was found. Histologically and immunohistochemically, a benign mature tridermic teratoma was diagnosed and epithelial structures, cartilage, bone, myxoid tissue, adipocytes, muscle cells, cystic spaces lined by squamous epithelium, feather follicles, melanocytes and variable neural and glial differentiation were recognized. By electron microscopy, desmosomes, keratin bundles, dense core neurosecretory granules, aberrant Z-line material and Luse bodies were found. To our knowledge, this is the first report of tridermic benign intracoelomic teratoma of a duck in which an extensive immunohistochemical and electron microscopic examination has been performed and in which a common neural and glial differentiation has been demonstrated., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

An 18-month-old, female, spayed domestic ferret (Mustela putorius furo) was presented for progressive hind limb paresis of 1 week duration. The ferret was mentally appropriate but cachexic and ataxic with neurological deficits, which localized the lesion to the lumbosacral region. A depression in the lumbosacral spine was associated with discomfort on palpation. Results of whole body radiographs were consistent with an abnormal angle between vertebrae L6 and S1, which resulted in hyperflexion of the spine. The ferret was euthanized, and histopathological examination revealed an intramedullary lumbosacral teratoma effacing much of the spine in the region of the mass.

This is the first report of a primary, spontaneous and, most probably, congenital teratoma in a domestic turkey, localized in front of the left eyeball. The unique localization allowed surgical excision of the tumour. The histopathological examination revealed that the tumour included structures derived from all three germ cell layers: ectoderm, mesoderm and endoderm (e.g. cartilaginous, osseous, haematopoietic, fibrous, nervous, glandular, squamous epithelial and smooth muscle tissues). The presence of epithelial cells as well as smooth muscle cells was confirmed using anti-cytokeratin and anti-desmin antibodies, respectively. The proliferative activity of the tumour cells was confirmed using proliferating cell nuclear antigen immunostaining. The other cases of teratoma in wild and domestic birds are reviewed briefly.

Teratomas commonly occur in the testis and ovary, whereas in the uterus they are rare. The authors report findings for a mass detected in the uterus of a 26-week-old mouse in a colony of C57BL/6 bred in their laboratory. The mass was located in the endometrium and protruded into the lumen. Histopathologically, it consisted of abnormal diploblastic or triploblastic tissues. Bone with a growth plate and myeloid cells, as well as cartilage, was mainly observed. It also included melanocytes, exocrine gland-like cells, striated muscle, and neuron-like cells. While these tissues were accompanied by extensive necrosis, all of them were well differentiated and lacked features of malignancy, such as invasion and metastasis. This mouse had experienced parturition, but fetal tissue was not observed in the lesion. Therefore, the lesion was diagnosed as a benign teratoma, which was spontaneously developed in the uterus.

A 4-month-old kitten was presented with a large mass over the temporal area involving the base of the left ear. Cytological evaluation of a fine-needle aspirate was not diagnostic. Computed tomography was used to determine tumor extent. Surgical resection was performed, which included parts of the orbital rim, masticatory muscles, the complete ear canal, and the pinna. Reconstruction of the ocular muscles was performed, and the skin defect was reconstructed using a single pedicle advancement flap. Despite unilateral facial paralysis, postoperative clinical function was excellent and aesthetics were good. Histological examination revealed the tumor to be a teratoma. After a follow-up period of 3 years, no signs of recurrence were evident. Extragonadal teratomas should be considered in the differential diagnosis when young animals are presented with a growing mass located outside the abdominal cavity. Surgical excision of a mature teratoma can be considered curative.