Diagnosis and Treatment of Anaplastic Mammary Carcinoma in a Sugar Glider (Petaurus breviceps)

A 9-year-old female sugar glider (Petaurus breviceps) was evaluated for a tissue mass near the marsupium. Ultrasonography identified a vascular mass originating from the right mammary gland. Fine-needle aspiration was suggestive of a malignant neoplasm. The glider was anesthetized and the tumor was removed, and this was followed by strontium-90 plesiotherapy to the tumor bed in an attempt to decrease local recurrence. Histopathology revealed an anaplastic mammary carcinoma. The glider was euthanized less than 14 days after the procedure owing to self-mutilation behavior of unknown etiology. This report is the first to describe the clinical presentation, diagnostics, therapeutics, and treatment response for a sugar glider with mammary neoplasia.     

Calvarial Osteoma with Cranial Vault Invasion in the Skull of a Ferret (Mustela putorius furo)

Osteoma is an uncommon tumor found in various animal species and is particularly rare or underreported in ferrets. A 2-year-old neutered male ferret (Mustela putorius furo) presented with an asymmetrical firm mass affecting the right dorsolateral skull. Radiographic images and computed tomography scans revealed a well-marginated mineralized mass involving the dorsal right calvarium that was growing concentrically into the cranium. A surgical biopsy sample was obtained and yielded a cytological diagnosis of sarcoma with reactive osteoblasts and osteoclasts and a histopathological diagnosis of osteoma. It was suspected that only the outer bony rim of the mass was submitted for histopathological evaluation, thereby adversely affecting the diagnostic quality of the sample. Based on interpretation of the combined imaging, cytological, and histopathological findings, a multilobular tumor of bone was suspected. Because of reduction in quality of life, the animal was euthanized 4 months after presentation, and postmortem examination yielded a definitive diagnosis of osteoma. This is the first report of an osteoma with cranial vault invasion in a ferret and is one of very few reports of this tumor diagnosed in this species. Lack of neurological signs in the patient, marked and extensive growth of the mass over several months, and the similar clinical appearance to other bony tumors leading to diagnostic ambiguity contributed to the distinctiveness of this case.     

Spontaneous Extraskeletal Osteosarcoma in a Rabbit (Oryctolagus cuniculus): Histopathological and Immunohistochemical Findings

A spontaneously occurring subcutaneous mass in the left forelimb of a nine-year-old rabbit (Oryctolagus cuniculus) was examined histopathologically and immunohistochemically. Clinically, edema and hemorrhage were seen around the mass. No connection of the tumor mass to the appendicular skeleton was found. The tumor was arranged in a solid growth pattern and irregular bundles, and neoplastic cells were polygonal to spindle-shape. Osteoid (positive for osteocalcin) and multinucleated giant cells were diffusely or focally seen. Neoplastic cells were positive for vimentin, osterix and Ki-67, indicating the nature of osteoblasts with proliferating activity, but negative for α-smooth muscle actin, desmin or CD204. Based on these findings, a diagnosis of extraskeletal osteosarcoma was made, a very rare tumor both in laboratory and pet rabbits.     

Spontaneous Rhabdomyosarcoma in a Common Marmoset ( Callithrix jacchus )

The common marmoset (Callithrix jacchus) is now widely used in various research fields, including toxicology. However, information about the background pathology of this species is scarce. Here, we report a case of rhabdomyosarcoma that spontaneously occurred in a common marmoset. A 44-month-old male common marmoset was euthanized due to bilateral hind limb paralysis. At necropsy, a 2×2×5-cm intramuscular mass was observed in the lower right back. Histologically, the mass was mainly composed of interlacing bundles of spindle-shaped tumor cells. Immunohistochemically, the tumor cells were positive for myogenin, desmin, vimentin and alpha-smooth muscle actin. Ultrastructurally, the tumor cells contained bundles of myofilaments with Z-band-like structures. Thus, the tumor was diagnosed as a rhabdomyosarcoma. To our knowledge, this is the first report of spontaneous rhabdomyosarcoma that was definitely diagnosed in the common marmoset.     

PARACLOACAL GLAND CARCINOMA IN A SUGAR GLIDER (PETAURUS BREVICEPS)

A male sugar glider (Petaurus breviceps) was presented to the National Taiwan University Veterinary hospital for repeated self-mutilation of the cloacal region. After correction of husbandry deficiencies and medical management of the lesion, the condition improved but a pericloacal mass was found. Surgical removal of the mass resolved the self-mutilation, and a dorsal paracloacal gland carcinoma was diagnosed on histopathological examination. Straining to defecate and a pericloacal mass could indicate neoplasia in sugar gliders. A tumor should be differentiated from chronic inflammation, infection, paracloacal gland impaction, and hyperplasia. Surgical removal is recommended as a treatment for paracloacal gland carcinoma in sugar gliders. Further monitoring is suggested after surgical removal of the tumor.     

Spontaneous Adenosquamous Carcinoma with Rapid Growth and EMT-like Changes in the Mammary Gland of a Young Adult Female BALB/c Mouse

This study histopathologically and immunohistochemically investigated a spontaneously occurring single mass subcutaneously located in the left lower abdomen of a female BALB/cAJcl−nu/+ mouse at 10 weeks of age. The mass was about 20 × 15 × 10 mm in size after formalin fixation; nevertheless, it was not detected by clinical observations at 9 weeks of age. H&E staining revealed the tumor origin was epithelial and probably arose from the mammary gland, and the tumor cells demonstrated a squamous, acinar or polyhedral/basal pattern. A cell kinetics analysis revealed that many of the tumor cells of the squamous, acinar or polyhedral/basal component were positive for PCNA and cyclin D1, although there were a few of TUNEL-positive tumor cells in all of the components. An epithelial/mesenchymal analysis demonstrated that most of the tumor cells of the squamous and acinar components contained keratin and E-cadherin; however, most of the tumor cells of the polyhedral/basal component were less or very weakly positive for these markers. The tumor cells of the squamous component were negative for vimentin and SMA; however, many of the tumor cells of the polyhedral/basal component exhibited vimentin. In addition, expression of SMA was confirmed in some tumor cells of the acinar and basal components. Based on the microscopic and immunohistochemical characterizations, the tumor was diagnosed to be adenosquamous carcinoma that originated from the mammary gland with rapid growth, and the tumor cells demonstrated epithelial-mesenchymal transition-like changes.     

Adenosquamous Carcinoma of the Trachea in a Domestic Ferret (Mustela putorius furo)

A 4-year-old, castrated, male domestic ferret (Mustela putorius furo) was evaluated for a possible upper respiratory tract infection and wheezing for approximately 3 weeks. Supportive care for a suspected upper respiratory tract infection was initiated; however, the patient became progressively more dyspneic over the next 48 hours. A possible tracheal mass was identified upon thoracic radiographic imaging of the ferret. Tracheoscopy and a computed tomography scan of the neck and thorax confirmed the presence of a tracheal mass approximately 3 cm from the larynx obstructing 80% of the tracheal lumen. Rather than pursuing surgical resection, the owners elected humane euthanasia. An adenosquamous carcinoma of the trachea was diagnosed after histologic analysis. This tumor type has been diagnosed in the lungs of ferrets that were experimentally exposed to carcinogens found in cigarette smoke; however, there are no previous reports of this or any other tumor type associated with the ferret trachea. A tracheal mass causing a partial upper airway obstruction should be considered within the differential disease diagnosis list when a ferret is presented with dyspnea.     

Cutaneous melanoma in a red-footed tortoise (Chelonoidis carbonaria)

There are few clinical reports of melanomas in reptiles. A 10-year-old male red-footed tortoise (Chelonoidis carbonaria) was referred to the Veterinary Hospital presenting with an ulcerated mass in the lateral aspect of the left pelvic limb. Radiographs demonstrated swelling and increased soft tissue density overlying the femur, tibia, and fibula, without bone involvement. Fine-needle aspiration cytology revealed innumerable round cells, with a defined cytoplasm filled with fine brown-black granules (melanin), which were considered well-differentiated melanocytes, suggesting a case of cutaneous melanoma. The mass was surgically removed. It was encapsulated and had an abundant blood supply. Histopathological examination revealed a well demarcated and encapsulated neoplastic proliferation of mesenchymal cells, with high cellularity and moderate fibrous stroma. Lymphangiectasia in the dermis adjacent to the tumor was also observed. Immunohistochemistry confirmed the diagnosis, with cells staining positive for Melan-A antibody being observed in neoplastic proliferation, adjacent dermis, inside lymphatic vessels, and invading the delimiting tumor's capsule. There was no evidence of local or systemic recurrence of the neoplasm over 500 days after removal. Chelonians can be affected by cutaneous melanomas. Surgical removal in this case was curative.     

Imatinib mesylate treatment in a dog with gastrointestinal stromal tumors with a c-kit mutation

A 13-year-old spayed mixed-breed dog was diagnosed with a gastrointestinal stromal tumor (GIST) after histopathological examination of an abdominal mass. Five months after surgical resection of the tumor, we detected the recurrence of GIST with multiple disseminated abdominal lesions. A sequence analysis of cDNA obtained from a biopsy of the recurrent tumors revealed a mutation within exon 9 of the c-kit gene (1523A>T, Asn⁵⁰⁸Ile), which has been shown to cause ligand-independent phosphorylation of the KIT protein in GISTs and canine mast cell tumors (MCTs). Upon detection of the recurrent tumors, we initiated treatment with imatinib mesylate (10 mg/kg, q 24 hr). After 2 months, the dog achieved complete remission. Our findings indicate that canine GIST, and possibly MCT, may be responsive to molecular-targeted therapy.     

Ovarian adenocarcinoma with metastases in a white rhinoceros

A 36-y-old white rhinoceros (Ceratotherium simum) was presented with respiratory distress, sanguineous vaginal exudate, and anorexia. The clinical signs progressed over 40 d, and the rhinoceros died. Autopsy revealed significant ascites; a unilateral, 12.5-cm diameter, polypoid mass in the left ovary; a white, firm transmural mass in the right uterine horn; a white, friable mass in the lung; and white-to-tan, friable small nodules in the diaphragm. Histologic examination revealed similar neoplastic cells in the masses in all 4 locations, composed predominantly of epithelial cells proliferating in a tubulopapillary pattern with significant nuclear atypia and numerous atypical mitotic figures (18–42 per 2.37 mm²). Immunohistochemistry for CK7 (cytokeratin 7) and CK20 (cytokeratin 20) suggest that the ovarian, pulmonary, and diaphragmatic lesions were of ovarian origin and that the ovary was the primary tumor site.     

Nephroblastoma in a Koi (Cyprinus carpio)

A cachexic 2-year-old koi (Cyprinus carpio) presented with progressive distension of the coelom (1-month period) and anorexia of 2 days' duration. The fish had been maintaining a normal swimming position, although it was often observed low in the water column. Water quality was within normal limits. A skin scrape, fin clip, and gill clip were unremarkable. The respiration rate (opercular movement) was elevated at 100 breaths per minute. Blood chemistry values demonstrated a hypoalbuminemia (1.3 g/dL), elevated uric acid (1.3 mg/dL), elevated creatine kinase (>14,000 U/L), and hyperkalemia (3.9 mmol/L). Ultrasound revealed a fluid-filled coelom and a soft tissue mass containing large vessels filling most of the coelomic cavity. Fine-needle aspirates of the mass were nondiagnostic, though a poorly exfoliating mesenchymal tumor was suspected. The mass was surgically excised. Pathological examination of the mass revealed it to be a poorly demarcated and unencapsulated neoplasm forming 3 histological patterns in which a spindle cell stromal component predominated over an intermediate-sized blastema and much smaller tubular patterns. These features were most consistent with a nephroblastoma. The koi survived 5 days postoperatively but remained low in the water column and was found dead on day 6. A full necropsy of this patient was not performed.     

Radiotherapy of a recurrent ossifying fibroma in the paranasal sinuses of a horse

A 7-year-old female Thoroughbred was admitted with a history of labored breathing, stridor, and exercise intolerance. Examination revealed a mass in the left paranasal sinuses that was determined to be an ossifying fibroma. Initial treatment consisted of surgical removal of the mass alone; however, the mass recurred 9 months after surgery. The mass was again removed, and adjunctive radiotherapy consisting of 3,000 cGy of cobalt radiation was administered. This time, the tumor did not recur for > 6 years. A third surgery was performed to remove the mass, and adjunctive radiotherapy consisting of 4,000 cGy of photon beam radiation from a linear accelerator was administered. The mass did not recur during the subsequent 3 years. Ossifying fibromas are uncommon tumors that frequently recur if incompletely excised. Results in this horse suggest that adjunctive radiotherapy may delay or prevent tumor recurrence in affected horses.     

Forelimb amputation for treatment of a peripheral nerve sheath tumor in an African pygmy hedgehog

CASE DESCRIPTION: A 6-year-old female African pygmy hedgehog was evaluated because of a mass of unknown duration on the lateral aspect of the right shoulder region. CLINICAL FINDINGS: A fine-needle aspirate of the mass was collected for cytologic examination; findings were consistent with a spindle cell tumor. A CBC, plasma biochemical analyses, and whole-body radiography revealed no other abnormalities. TREATMENT AND OUTCOME: An initial surgery performed in an attempt to remove the mass with preservation of the limb failed in that tumor-free surgical margins were not obtained. Histologically, the mass was identified as a peripheral nerve sheath tumor (neurofibrosarcoma). A second surgery to amputate the forelimb was successful. After 1 year, there had been no further development of peripheral nerve sheath tumor at this or other sites. CLINICAL RELEVANCE: In African pygmy hedgehogs, potential differential diagnoses for a subcutaneous mass should include peripheral nerve sheath tumor. If necessary, forelimb amputation can be performed successfully in this species with procedures modified from those used in dogs. Information gathered during the treatment and recovery of the hedgehog of this report may assist practicing veterinarians in counseling owners of hedgehogs that are undergoing forelimb amputation with regard to the course of recovery that may be expected following this procedure.     

Swim bladder tumor in the young adult scoliotic medaka (Oryzias latipes)

A swim bladder tumor was detected in one scoliotic medaka aged 22 weeks. The tumor was located in the dorsal abdominal cavity, with maximum dimension of 1,850 × 1,500 µm. No swim bladder lumen was identified, and the region where the swim bladder lumen would have been located, was replaced with adipose tissues. The tumor was a non-invasive, expansile, and encapsulated solid mass with a few cysts, and comprised a homogenous population of well-differentiated, densely packed, gas glandular epithelium-like cells. The tumor mass was connected to a rete mirabile that showed a hyperplastic capillary plexus; however, the tumor cells did not invade the rete mirabile, thereby revealing that the tumor was an adenoma originating from the gas glandular epithelium of the swim bladder. Since proliferative lesions in the swim bladder have been reported in some teleosts with skeletal deformations, including medaka, the occurrence of a spontaneous swim bladder tumor in teleosts is considered to be closely associated with various types of skeletal deformation, and spinal curvature in particular.     

Clinical Pharmacokinetics and Effects of Vincristine Sulfate in Dogs with Transmissible Venereal Tumor (TVT)

This study was conducted to evaluate the pharmacokinetic characteristics of vincristine and their correlation with its clinical effects in dogs with transmissible venereal tumor (TVT). Dogs with TVT were intravenously administered vincristine sulfate at a dose of 0.7 mg/m² of body surface area. Blood samples were collected starting from 5 min to 48 hr after drug administration. The plasma concentration of vincristine was determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The pharmacokinetic parameters of vincristine were characterized using a two-compartmental pharmacokinetic model. The volume of distribution, distribution half-life, elimination half-life and plasma clearance were 0.660 ± 0.210 l/kg, 21.5 ± 6.90 min, 47.6 ± 14.2 min and 0.010 ± 0.001 l/min/kg, respectively. Tumor regression was determined at weekly interval by a physical examination and histopathological analysis. In our study, three to eight administrations of vincristine at a dose of 0.7 mg/m² were able to induce a complete tumor regression without any evidence of gross lesion of disease. Therefore, this investigation provides the pharmacokinetic characteristics of vincristine in dogs with TVT, which may be used as an integration tool to gain a better understanding of the disposition properties of the drug and the correlation of these properties with the drug’s clinical effects. In addition, we validated the LC-MS/MS method and found that it is suitable for the pharmacokinetic study of vincristine in dog plasma.     

一例犬前肢血管周细胞瘤的病理及免疫组化分析

血管周细胞瘤是一种软组织肉瘤,起源于毛细血管壁的周细胞。在本报道中,描述了一只11岁中华田园犬的左腿腕关节肿块。为确定肿块性质,采用影像学、细胞学和病理学检查加以诊断。X光检查显示肿瘤始于软组织,肿物界限清晰;细胞学检查显示细胞呈梭形,核仁明显,细胞核大小不一;病理组织学结果显示存在围绕血管的梭形细胞;免疫组织化学结果显示波形蛋白和α-SMA阳性表达,desmin和S-100阴性表达,肿瘤组织中PCNA阳性肿瘤细胞的数量大于25%,Masson trichrome染色显示肿瘤组织中胶原纤维的含量少。结合病理学及免疫组化确诊为血管周细胞瘤。     

ADNEXAL CYSTADENOMA IN A BEARDED DRAGON (POGONA VITTICEPS)

An adult female bearded dragon (Pogona vitticeps) presented to the University of Georgia Veterinary Teaching Hospital for an area of swelling affecting the left eye of approximately 3 years’ duration. Upon examination, the left eye could not be evaluated due to an extensive periorbital mass effect. Hematologic and advanced diagnostic testing were recommended, but due to financial concerns the owner declined. Ultimately, the patient was humanely euthanized and was submitted for necropsy. The mass was diagnosed via histopathology as a cystadenoma of the eyelid. Phthisis bulbi of the left eye with granulomatous inflammation was also observed.     

Peripheral nerve sheath tumor of the diaphragm with osseous differentiation in a one-year-old dog.

A 12-month-old, spayed female German shepherd dog was referred to the Veterinary Teaching Hospital for repair of a diaphragmatic hernia. Abdominal exploration revealed an intact diaphragm, but thoracic exploration revealed a large mass originating from the diaphragm. Resection of the mass was incomplete and required reconstruction of the diaphragm. On histopathology, the mass was composed mainly of spindle-shaped cells with occasional areas of osseous and chondroid tissue. The tumor was diagnosed as a peripheral nerve sheath tumor (PNST) with chondro-osseous differentiation. The dog was released four days after surgery; however, she began having difficulty breathing seven days after discharge, and the owners elected euthanasia. A necropsy was not performed. This is the first known report of a PNST originating in the diaphragm of a dog.