Intestinal hemangiomas in 8 horses.

This retrospective study describes 8 cases of intestinal hemangioma diagnosed in horses during postmortem examination or surgical biopsy at the University of Tennessee College of Veterinary Medicine. In all cases, the intestine was the sole organ affected, and lesions were focal (3/8) or multifocal (5/8). Nodules were most commonly within the small intestine (7/8), particularly the jejunum (5/7). One case was in the left dorsal colon, which is the first report of hemangioma in the large colon of a horse. Lesions were discrete, raised, smooth, black to red, and ranged from 2 to 15 mm in diameter. Microscopically, all lesions were cavernous type and mural, most frequently within the muscularis (6/8). A majority of cases occurred in middle aged to older horses (average age of 19.3 years), and no breed or sex predilections were identified. The hemangiomas were considered incidental findings.

RABIES DIAGNOSIS AND RESPONSE TO VACCINATION IN SOUTHERN TAMANDUA (TAMANDUA TETRADACTYLA).

Rabies has rarely been described in Xenarthra, and rabies vaccine response has not been documented. A southern tamandua (Tamandua tetradactyla) presented with nonspecific clinical signs and was euthanatized. Subsequently, immunohistochemistry and RT-PCR confirmed a rabies diagnosis. Following these tests, a group of eight captive tamanduas were vaccinated with a killed rabies vaccine, and titers were measured at the time of vaccination and 23 d later. One animal had day 0 titers suggestive of previous vaccination or exposure. All animals had detectable neutralizing rabies virus antibody titers after vaccination, but one animal failed to meet the World Organization for Animal Health's definition for adequate vaccination (≥0.5 IU/ml), and two other animals had low antibody titers (0.56 and 0.6 IU/ml). Rabies should be considered as a possible cause of illness in tamanduas, and rabies vaccination may be a useful preventative measure when anthropic interaction through medical care or ambassador roles is occurring.

Postmortem Evaluation of Cardiac Valvular Disease in Bald Eagles (Haliaeetus leucocephalus) and a Golden Eagle (Aquila chrysaetos).

Limited data are available regarding cardiac diseases in birds of prey despite their prevalence in these avian species. Literature regarding valvular lesions in birds of prey is scarce and includes single reports of left atrioventricular valvular endocarditis in an adult, free-ranging, male bald eagle (Haliaeetus leucocephalus) and aortic valvular endocarditis in an adult, free-ranging, female red-tailed hawk (Buteo jamaicensis). The purpose of this study was to evaluate the prevalence, signalment, gross necropsy findings, and histologic lesions of valvular lesions in eagles. In this retrospective study, necropsy reports for 24 free-ranging and captive eagles were evaluated over a 15-year period (July 3, 2006-February 28, 2021). Six (25%; 95% confidence interval: 8.9-58.9) birds, 5 bald eagles and 1 golden eagle (Aquila chrysaetos), met the inclusion criteria. Five (83.3%) of the 6 birds had valvular degeneration, 2 (33.3%) had endocarditis, and Staphylococcus aureus was cultured from 1 (16.7%) of the endocarditis cases. The 6 eagles with valvular lesions were all captive adults. Four of the birds were female (66.7%), and the aortic and left atrioventricular valves were equally affected. Acute or chronic cerebral infarcts were present in all 6 birds. Valvular cardiac disease should be considered as a differential diagnosis in eagles exhibiting respiratory distress, neurologic signs, syncope, or in cases of sudden death.

Translocation of an Anteater (Tamandua tetradactyla) Infected with Rabies from Virginia to Tennessee Resulting in Multiple Human Exposures, 2021.

On August 16, 2021, the Tennessee Department of Health (TDH) was notified of a positive rabies test result from a South American collared anteater (Tamandua tetradactyla) in Washington County, Tennessee. Tamanduas, or lesser anteaters, are a species of anteater in which rabies has not previously been reported. The animal was living at a Tennessee zoo and had been recently translocated from a zoo in Virginia. TDH conducted an investigation to confirm the rabies result, characterize the rabies variant, and ascertain an exposure risk assessment among persons who came into contact with the tamandua. Risk assessments for 22 persons were completed to determine the need for rabies postexposure prophylaxis (rPEP); rPEP was recommended for 13 persons, all of whom agreed to receive it. Using phylogenetic results of the virus isolated from the tamandua and knowledge of rabies epidemiology, public health officials determined that the animal was likely exposed to wild raccoons present at the Virginia zoo. This report describes expansion of the wide mammalian species diversity susceptible to rabies virus infection and summarizes the investigation, highlighting coordination among veterinary and human public health partners and the importance of preexposure rabies vaccination for animal handlers and exotic zoo animals.

Medullary bone in male budgerigars (Melopsittacus undulatus) with testicular neoplasms.

Medullary bone is a calcium-rich, labile bone normally occurring in female birds with each egg-laying cycle. The stimulus for formation of medullary bone is, in part, the cyclic increase in serum estrogens produced by preovulatory ovarian follicles. Increased bone density due to formation of medullary bone, particularly in pneumatic bones, has been termed polyostotic hyperostosis, even if physiologic. This study investigated the formation of medullary bone in nonpneumatic (femur) and pneumatic (humerus) bones in sexually mature male budgerigars submitted for autopsy. Of the 21 sexually mature male budgerigars submitted for autopsy, 7 (33%) had medullary bone in 1 or more bones examined. All 7 male budgerigars with medullary bone had a testicular neoplasm, which was morphologically consistent with a testicular sustentacular cell tumor, seminoma, or interstitial cell tumor. Medullary bone was not present in the 14 cases with other diseases. Medullary bone formation in pneumatic and nonpneumatic bones can occur in male budgerigars with testicular neoplasms. Radiographic increases in medullary bone density, particularly in the humerus, could provide antemortem indication of testicular neoplasia in male budgerigars.

Periarticular plasma cell tumors in cats.

This report describes periarticular plasma cell tumors with abundant amyloid in 11 cats. The tarsus was the most commonly affected joint (10/11), and the masses were often circumferential around the tarsal joint, involving the dermis and subcutis. The 2 cases in which synovium was examined had neoplastic cells expanding the synovium. Three of the 5 cases staged radiographically had bony lysis of the affected joint. Cutaneous biopsy specimens often consisted of more amyloid than plasma cells, making the diagnosis difficult on small samples. Follow-up information was available in 7 cases; in those cases, the median survival was 194 days (range 53-671 days). Four cases had confirmed metastases, most often to regional lymph nodes, liver, and spleen. Although canine cutaneous plasma cell tumors are typically benign, those with abundant amyloid surrounding the joints of cats may involve deeper tissues and have a more aggressive behavior. These tumors can be difficult to diagnose due to low cellularity and abundant amyloid.

International Guidelines for Veterinary Tumor Pathology: A Call to Action.

Standardization of tumor assessment lays the foundation for validation of grading systems, permits reproducibility of oncologic studies among investigators, and increases confidence in the significance of study results. Currently, there is minimal methodological standardization for assessing tumors in veterinary medicine, with few attempts to validate published protocols and grading schemes. The current article attempts to address these shortcomings by providing standard guidelines for tumor assessment parameters and protocols for evaluating specific tumor types. More detailed information is available in the Supplemental Files, the intention of which is 2-fold: publication as part of this commentary, but more importantly, these will be available as "living documents" on a website (www.vetcancerprotocols.org), which will be updated as new information is presented in the peer-reviewed literature. Our hope is that veterinary pathologists will agree that this initiative is needed, and will contribute to and utilize this information for routine diagnostic work and oncologic studies. Journal editors and reviewers can utilize checklists to ensure publications include sufficient detail and standardized methods of tumor assessment. To maintain the relevance of the guidelines and protocols, it is critical that the information is periodically updated and revised as new studies are published and validated with the intent of providing a repository of this information. Our hope is that this initiative (a continuation of efforts published in this journal in 2011) will facilitate collaboration and reproducibility between pathologists and institutions, increase case numbers, and strengthen clinical research findings, thus ensuring continued progress in veterinary oncologic pathology and improving patient care.

A RETROSPECTIVE STUDY OF BRAIN LESIONS IN CAPTIVE NONDOMESTIC FELIDS.

This retrospective study identified and characterized brain lesions in captive nondomestic felids from a large cat sanctuary. Necropsy reports from January 2002 through December 2018 were examined, and gross images and microscopic slides were reviewed from individual cats, where available. In total, 255 cats met the following inclusion criteria: complete necropsy report available, brain examined grossly or microscopically, and age of >1 mon. Of the 255 cats, 49 cats (19%) were determined to have brain lesions. Eleven different felid species, as well as one captive-bred hybrid (liger), were included in the study, with tigers (Panthera tigris) (55%) and lions (Panthera leo) (18%) being the most common species. Lesions were grouped into six etiologic categories: neoplastic (32%), vascular (26%), inflammatory or infectious (20%), congenital (9%), idiopathic (7%), and metabolic (6%). Not included in these categorized lesions were previously undescribed amphophilic globules in the cerebral cortex of many cats with and without other brain lesions; these were in 95% of lion and 93% of tiger brains where the cerebral cortex was available for histologic examination. These globules were not associated with clinical disease. The histopathologic and gross brain changes documented in this study provide insight into specific diseases and pathologic processes that affect the brains of captive large cat populations.

Cutaneous Mycobacteriosis Caused by Mycobacterium kansasii in a Yellow-naped Amazon Parrot (Amazona auropalliata).

An approximately 25-year-old, female, yellow-naped Amazon parrot (Amazona auropalliata) was evaluated for a chronic, raised, ulcerative mass on the lateral aspect of the left thigh. Histopathology of an excisional biopsy revealed severe, chronic, multifocal-to-coalescing, ulcerated dermal and subcutaneous granulomas. No infectious organisms were observed on Ziehl-Neelsen or Gomori methenamine silver stains. The parrot was treated with oral sulfamethoxazoletrimethoprim and meloxicam. When reexamined 2 weeks later, the biopsy site had healed. Surgical biopsies were resubmitted 14 months after the original presentation due to recurrence of similar ulcerative lesions on the right leg. Histopathology revealed a similar inflammatory pattern, and hematoxylin-eosin, Ziehl-Neelsen, and silver stains on the biopsy samples were all negative. A Fite-Faraco stain revealed rare acid-fast bacilli throughout the lesion. Tissue polymerase chain reaction test was negative for Mycobacterium avium and Mycobacterium genavense. Mycobacterial culture and subsequent genotyping revealed Mycobacterium kansasii. Mycobacterium kansasii is a significant cause of mycobacteriosis in humans and, therefore, should be considered a potential zoonotic organism. This report describes an unusual primary cutaneous presentation of avian mycobacteriosis.

Synovial Cysts and Myxomas in 16 Cats.

This report describes the clinical and pathologic characteristics of cystic and myxomatous lesions of synovial joints in 16 cats. The average age was 13.4 years. The elbow was most commonly affected (12/16), and all lesions were unilateral. Degenerative joint disease was a frequent concurrent but bilateral condition. The lesions consisted of fluid-filled cysts lined by synoviocytes (3 cases), solid foci of stellate cells in a myxomatous matrix (2 cases), or a combination of the two (11 cases). In some cases there were areas of transition between the cystic and myxomatous lesions. Mitoses and other features of malignancy were rare to nonexistent. In the 13 cats with follow-up information, the lesion gradually increased in size over a period of years. None of the cats died or were euthanized because of this lesion. We propose that some cats with degenerative joint disease develop synovial cysts, which have the potential to transform to a synovial myxoma.

Natural Canine Distemper Virus Infection in Linnaeus's 2-Toed Sloths (Choloepus didactylus).

An outbreak of canine distemper virus in a private zoo in eastern Tennessee in July 2016 led to fatal clinical disease in 5 adult, wild-caught Linnaeus's 2-toed sloths (Choloepus didactylus). Clinical signs included hyporexia, lethargy, mucopurulent nasal discharge, and oral and facial ulcers. At necropsy, affected animals had crusts and ulcers on the lips, nose, tongue, and oral cavity. Microscopically, all sloths had widespread, random, hepatic necrosis; lymphoid depletion; and bronchointerstitial pneumonia. The central nervous system did not contain gross or histopathologic lesions in any of the 5 sloths, although immunoreactivity for viral antigen was present within vessel walls. Epithelial cells and histiocytes within numerous organs contained intranuclear and intracytoplasmic inclusions and occasional syncytial cells. Canine distemper virus was confirmed with immunohistochemistry and virus isolation. Viral sequencing identified the novel American-4 strain prevalent in eastern Tennessee wildlife. This is the first pathologic characterization of canine distemper virus infection in sloths (family Choloepodidae, order Pilosa) and emphasizes the significant morbidity and mortality in this species.

Toxocara canis Larval Migration Causing Verminous Pneumonia in Fading Puppies From 2 Scottish Terrier Litters.

Migration of vertically transmitted Toxocara canis larvae through the liver and lungs is poorly documented as a cause of periparturient mortality in puppies. This case series describes 4 cases of fading puppies in 2 litters from 2 different bitches owned by the same breeder. Of the 4 cases, 4 had verminous pneumonia, 2 had fibrinoid necrosis of pulmonary arterioles, 4 had hepatic necrosis and inflammation, 2 had hepatic thrombophlebitis, and 1 had tracheal occlusion. These lesions were associated with migrating nematode larvae morphologically consistent with T. canis. The identity of the larvae was confirmed by sequencing of a portion of the ITS-2 region of nuclear ribosomal DNA. The tissues involved are consistent with the known migration pathways of this parasite. The dam of the first litter was negative for Toxocara spp. and other intestinal parasites by fecal floatation. This report highlights the need to consider T. canis migration in the differential diagnosis of fading puppies.

GADOXETATE DISODIUM (GD-EOB-DTPA) CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF HEPATOCELLULAR CARCINOMA IN DOGS.

Hepatocellular carcinoma is the most common primary hepatic tumor in dogs and is amenable to surgical resection in many cases. Unfortunately, overlap of sonographic findings between benign and malignant hepatic lesions typically requires more invasive diagnostic tests to be performed (e.g., biopsy for histopathology). The availability of a noninvasive diagnostic test to identify hepatocellular carcinoma would be beneficial. The use of a liver-specific magnetic resonance imaging (MRI) contrast agent such as gadoxetate disodium (Gd-EOB-DTPA; Eovist® or Primovist®) has improved lesion detection in human patients. In this descriptive study, gadoxetate disodium contrast-enhanced MRI characteristics in dogs were evaluated in seven dogs (total of eight lesions). The imaging characteristics were variable with the exception of all lesions being hypointense to surrounding normal hepatic parenchyma on 3D T1-weighted gradient recalled echo images at all postcontrast time points. All lesions displayed signal intensity ratios less than 1, consistent with retained but impaired hepatocyte function. Hepatic lesions not identified on previous imaging were found in 3/7 patients which may affect surgical planning. In two patients, several hepatic nodules were identified during surgery which had not been visualized on MRI and were found to be benign on histopathology. This descriptive study reports the MRI characteristics of hepatocellular carcinoma in dogs using the liver-specific contrast agent gadoxetate disodium.

HYDROCEPHALUS IN THREE JUVENILE NORTH AMERICAN BLACK BEARS (URSUS AMERICANUS).

Hydrocephalus has been reported in a variety of species, including the North American black bear ( Ursus americanus ). This report describes three cases of hydrocephalus in this species from wild bears aged 3-4 mo considered retrospectively from necropsy records of one institution. Clinical signs included cortical blindness and ataxia. Primary gross findings were doming of the skull, gyri compression and flattening, and lateral ventricle dilation. Two cases had severe bilateral ventricular dilation with loss of the septum pellucidum; atrophy of the surrounding corpus callosum; and bilateral periventricular tears involving the caudate nuclei, internal capsule, and adjacent cerebrum. Histologically, the cases with periventricular tearing had severe axonal loss and degeneration, malacia, hemorrhage, and variable periventricular astrocytosis. All cases were likely congenital, given the bears' age and lack of an apparent acquired obstruction.

CLINICOPATHOLOGIC FEATURES OF MAMMARY MASSES IN CAPTIVE LIONS (PANTHERA LEO).

A multi-institutional retrospective analysis of 330 pathology accessions from 285 different lions found 15 captive, female African lions (Panthera leo) with confirmed mammary masses. Aside from the presence of a mammary mass, the most common initial clinical sign was inappetence. Histologic diagnoses were predominantly adenocarcinoma (n = 12), though two benign masses (mammary hyperplasia and a mammary cyst) and one squamous cell carcinoma were identified. Nine of 13 malignant tumors had metastasized to lymph nodes or viscera at the time of necropsy. Six lions with adenocarcinoma and two lions with benign mammary masses had received hormonal contraception, though little evidence of mammary lobular hyperplasia was seen in association with the adenocarcinomas. The most common concurrent disease processes found at necropsy were chronic urinary tract disease and other malignancies. These cases demonstrate that mammary malignancies occur in captive lions and frequently metastasize.

IMAGING DIAGNOSIS-SCLEROSING ENCAPSULATING PERITONITIS IN A DOG.

An approximately 5-month-old American Staffordshire terrier was presented with a history of recurrent peritoneal effusion. Abdominal radiographs and ultrasound showed a loculated effusion in the ventral abdomen with dorsal displacement of abdominal organs, hepatomegaly and rounding of liver and splenic margins. Computed tomography demonstrated centrally located gastrointestinal segments surrounded by a thin soft tissue band and a thickened peritoneal lining. At necropsy a fibrous membrane continuous with liver and splenic capsules encapsulated all abdominal organs. Microscopically the abdominal wall and fibrous capsule consisted of an irregular thick layer of hypocellular connective tissue. The final diagnosis was sclerosing encapsulating peritonitis.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Radiographic evidence of metaphyseal sclerosis secondary to canine distemper virus: 4 cases in juvenile dogs.

BACKGROUND: Metaphyseal sclerosis secondary to canine distemper virus has been described histopathologically, but its radiographic appearance has not been described. OBJECTIVES: Describe the radiographic appearance of metaphyseal sclerosis secondary to canine distemper virus in juvenile dogs as distinct from metaphyseal osteopathy (formerly called hypertrophic osteodystrophy). ANIMALS: Four dogs (2 intact females and 2 intact males) between 2.5 and 4 months of age presented to 2 different veterinary teaching hospitals. METHODS: Retrospective case series in which definitive diagnosis of canine distemper virus based on antemortem positive reverse transcription-polymerase chain reaction (RT-PCR) result or necropsy was required. RESULTS: All 4 dogs were presented for evaluation of neurologic abnormalities, respiratory signs, and lethargy; 2 dogs had gastrointestinal signs and ocular abnormalities. Radiographs on all patients featured multifocal, symmetric, metaphyseal sclerosis, with no evidence of lysis or changes to the adjacent growth plate. The metaphyseal sclerosis was most apparent at the proximal humeral diaphyses and other included long bones. Diagnosis of distemper was confirmed by necropsy (2 of 4 dogs) or positive RT-PCR results (2 of 4 dogs). Three dogs were euthanized because of progressive illness, and 1 dog was lost to follow-up. CONCLUSION AND CLINICAL IMPORTANCE: Identification of metaphyseal sclerosis on radiographs during diagnostic evaluation of young dogs should lead to a clinical suspicion of canine distemper virus infection. Sclerosis identified secondary to canine distemper virus is distinct from the necrosis and inflammation of metaphyseal osteopathy.

Magnetic Resonance Imaging in 50 Captive Non-domestic Felids - Technique and Imaging Diagnoses.

Magnetic resonance imaging (MRI) is the recognized gold standard for diagnostic imaging of the central nervous system in human and veterinary patients. Information on the use of this modality and possible imaging abnormalities in captive non-domestic felids is currently limited to individual case reports or small case series. This retrospective study provides information on technique and imaging findings in a cohort of cases undergoing MRI at an academic Veterinary Medical Center. The University of Tennessee College of Veterinary Medicine MRI database was searched for non-domestic felids undergoing MRI of the brain or spine from 2008 to 2021. Medical record data were recorded, and MRI studies were reviewed. Fifty animals met the inclusion criteria. The most common brain diseases were Chiari-like malformation (n = 8) and inflammatory conditions (n = 8). Other abnormalities included pituitary lesions (n = 5), brain atrophy (n = 2), and one each of metabolic and traumatic conditions. Fourteen animals had a normal brain MRI study. The most common spinal abnormality was intervertebral disc disease (n = 7). Other disorders included vertebral dysplasia (n = 2), presumptive ischemic myelopathy (n = 1), subdural ossification causing spinal cord compression (n = 1), and multiple myeloma (n = 1). Spinal cord swelling of undetermined cause was suspected in two animals, and seven patients had a normal MRI study of the spine. MRI is a valuable tool in the diagnostic workup of non-domestic felids with presumptive neurologic disease.