Table of Contents and Abstracts

This report describes a novel case of exostosis on the medial aspect of the sustentaculum tali, (ST) associated with tibiotarsal joint (TTJ) pathology, without involvement of the tarsal sheath or lateral digital flexor tendon. A 5-year-old Standardbred gelding was presented with right TTJ effusion and exercise-induced hind-limb lameness. Diagnostic imaging identified a columnar periosteal proliferation on the medial ST, accompanied by synovial effusion and joint capsule thickening; however, the tarsal sheath and lateral digital flexor tendon remained unremarkable. Although TTJ arthroscopy confirmed synovitis, it did not allow visualization of the exostosis. The lesion was successfully excised via an ultrasound-guided extra-articular surgical approach. Postoperative management included a structured rehabilitation program, resulting in a return to full-speed training by Day 76 with no recurrence of lameness. Follow-up evaluations demonstrated improved performance and complete resolution of TTJ effusion and associated swelling. This case highlighted the importance of multimodal imaging in identifying extra-synovial lesions of the ST and supported ultrasound-guided extra-articular removal as an effective surgical option for ST exostosis. Although the underlying cause of the lesion was uncertain, subclinical trauma was considered a likely contributing factor.

Key clinical message:
The ST is a horizontal bony projection on the plantaromedial aspect of the calcaneus. Due to its minimal soft-tissue coverage, it is particularly vulnerable to external trauma and subsequent osseous proliferation. Exostosis of the ST may result in impingement of the plantaromedial pouch of the tarsocrural (tibiotarsal) joint, contributing to joint irritation and secondary pathology. Accurate diagnosis and effective case management rely on the combined use of radiography and ultrasonography, which together enable detailed assessment of both osseous changes and associated soft-tissue structures.

A 7-month-old female Holstein-Friesian calf was presented with a lifelong history of failure to thrive. She was severely dehydrated on presentation. Venous blood gas and serum biochemistry analyses revealed mixed acid-base disturbances, including a hypochloremic metabolic alkalosis indicative of pyloric outflow obstruction. She also had acidic urine. The calf continued to decline and was euthanized. At necropsy, the pyloric opening was markedly narrowed and difficult to find. As there were no accompanying lesions such as inflammation, ulceration, or fibrosis, presumed congenital pyloric stenosis was diagnosed. Clinicians should include congenital pyloric stenosis on their list of differential diagnoses when examining a calf with pyloric outflow obstruction, even if the calf is older.

Key clinical message:
Hypochloremic metabolic alkalosis with paradoxic aciduria can occur with many causes of pyloric outflow obstruction. Other acid-base disturbances can also be present. In calves, congenital pyloric stenosis should be considered as a potential cause, even in animals that are no longer neonates.

A 6-year-old intact male dog was referred because of persistent hematuria despite multiple courses of antimicrobial therapy. Urogenital ultrasonography revealed a large, paraprostatic, uterus-like, fluid-filled structure containing echogenic fluid, associated with an adjacent large, heterogeneous mass located cranially and to the right of the lesion. These findings raised suspicion for malignant transformation of a uterus masculinus associated with persistent Müllerian duct syndrome. Exploratory laparotomy confirmed the presence of a uterus masculinus with blind-ended uterine horns, associated adhesions, and a large mass arising from the right cranial aspect. Surgical excision of the abnormal structure and orchiectomy were carried out. Histopathology confirmed an anaplastic carcinoma of Müllerian origin arising from persistent Müllerian duct remnants. The tumor exhibited highly aggressive biological behavior characterized by extensive local invasion. There was rapid clinical deterioration after surgery, including imaging findings consistent with pulmonary, hepatic, and peritoneal metastatic disease, ultimately leading to euthanasia 5 wk after diagnosis.

Key clinical message:
Persistent Müllerian duct remnants should be considered as a differential diagnosis for paraprostatic cavitary lesions in intact male dogs, even in the absence of cryptorchidism. Malignant transformation of a uterus masculinus, though rare, may exhibit highly aggressive biological behavior with rapid metastatic dissemination.

Two pet chinchillas were presented with acute anorexia and lethargy. Biochemistry revealed severe hyperglycemia and azotemia in both cases, with severe hyperkalemia in Case 1 and hyperphosphatemia in Case 2. Acidic urine with glucosuria and ketonuria was also observed in Case 1. Despite medical treatment including insulin therapy, both animals experienced a fulminant clinical course and died. Postmortem examination identified severe necrotizing pancreatitis with pulmonary congestion and edema in both cases. In addition, the chinchilla in Case 1 showed vasodilation with vascular necrosis and thrombosis in the pancreas and surrounding adipose tissues, whereas the animal in Case 2 displayed extensive renal medullary tubular necrosis with hemorrhage. The pathological findings suggested systemic inflammatory response syndrome with secondary hypotensive shock, acute renal failure, and multiple-organ dysfunction as the presumed causes of death.

Key clinical message:
Necrotizing pancreatitis should be considered early as a differential diagnosis in a chinchilla presented with acute circulatory compromise, renal dysfunction, and marked debilitation, particularly when severe hyperglycemia or diabetic-like metabolic abnormalities are present.

Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-D-glucose integrated with computed tomography (¹⁸F-FDG PET/CT) imaging identified infection and inflammation earlier and with higher sensitivity than other imaging modalities in human medicine. A small case series explored the use of ¹⁸F-FDG PET/CT for detecting the cause of fever of unknown origin in dogs. This report details clinical aspects and ¹⁸F-FDG PET/CT imaging in the workup and treatment of a 12-year-old dog that was presented obtunded with severe neutropenia and hypoglycemia secondary to suspected sepsis. The ¹⁸F-FDG PET/CT revealed moderate, patchy FDG avidity and soft-tissue swelling of the left carpus and tarsus (SUV max: 7.18 and SUV max: 5.58, respectively), moderate heterogeneous splenic and hepatic hypermetabolic activity (SUV max: 3.42), and bilaterally symmetric renal hypermetabolic activity (SUV max: 6.22) without appropriate flourine-18 fluorodeoxyglucose (¹⁸F-FDG) excretion. Other notable findings included marked, diffuse ¹⁸F-FDG uptake within all bone marrow spaces (SUV max: 15.47) and a generalized, mild lymphadenopathy with moderate hypermetabolic activity. Positive blood cultures confirmed sepsis. Clinical deterioration despite appropriate antibiotic and supportive therapy prompted euthanasia. Necropsy revealed lymphohistiocytic and neutrophilic necrotizing vasculitis with thrombosis and necrosis in heart, spleen, brain, and liver, consistent with septicemia. Enterococcus faecium was isolated from lungs, kidneys, and spleen; Serratia marcescens was isolated from lungs and kidneys. This is the first documented report of the use of ¹⁸F-FDG PET/CT for the diagnostic workup of a septic patient in veterinary medicine with corroborative necropsy findings to confirm PET/CT suspicion of disseminated septicemia.

Key clinical message:
Positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-D-glucose integrated with computed tomography imaging, which combines the functional, metabolic information from a PET scan with the high-resolution anatomical detail from a CT scan, should be considered as an adjunctive imaging modality for the diagnostic workup to identify focal and systemic infections in veterinary medicine. This is critical for immunocompromised animals in which timely and accurate diagnosis is of utmost importance, either for guiding case management and clinical outcome or for guiding owners through difficult decisions when the prognosis is guarded to poor.

Carotid body tumors are rare neuroendocrine neoplasms in dogs, and evidence-based treatment options for malignant or unresectable cases remain poorly defined. An 8-year-old castrated male French bulldog was presented with a large cervical mass accompanied by progressive respiratory distress, neurologic abnormalities, and exophthalmos. Computed tomography revealed multiple, highly vascularized cervical masses with extensive local invasion, including nasopharyngeal obstruction and intracranial extension. Partial surgical excision was undertaken for diagnostic purposes, and histopathologic examination confirmed carotid body carcinoma with intravascular invasion. Because of incomplete surgical resection and malignant features, targeted therapy was initiated. Based on in vitro chemosensitivity testing, toceranib phosphate was selected. Following treatment, clinical signs related to mass effect improved, nasopharyngeal obstruction was alleviated, and increased intratumoral necrosis was suspected on follow-up imaging. Adverse effects were mild and manageable. The dog remained clinically stable for ~5 mo after targeted therapy but was subsequently lost to follow-up. On a later follow-up via telephone, the owner reported that the dog had died 6 mo after initiation of targeted therapy.

Key clinical message:
This case suggests that toceranib may represent a potential therapeutic option for dogs with unresectable or incompletely resected carotid body carcinoma.

Objective
The objective was to determine the effects of multimodal rehabilitation interventions on Canine Brief Pain Inventory (CBPI) pain scores in dogs diagnosed with osteoarthritis (OA), and to determine whether effects differed between formal in-clinic versus outpatient rehabilitation.

Animals and procedure
Medical records from between 2022 and 2024 were reviewed for dogs with OA that were presented to a rehabilitation specialist. Each dog’s caregiver completed a CBPI at both the initial evaluation and 1st follow-up visit. Dogs were allocated into 2 groups: those that received in-clinic rehabilitation and those that received outpatient interventions. Both groups received customized, multimodal plans to address their OA signs. Pain severity scores (PSS), pain interference scores (PIS), and overall interference scores were compared between groups. A 2-sample Student’s t-test or a Fisher’s exact test was used to compare groups, with a statistical significance level of 0.05.

Results
A total of 79 dogs were included in the study. There were no differences between dogs enrolled in in-clinic rehabilitation versus outpatient rehabilitation for sex, age, weight, or body condition score (P = 0.541, P = 0.26, P = 0.58, P = 0.33, respectively). The PSS and PIS had improved at the 1st recheck in both groups (in-clinic: P = 0.01 and P = 0.03; outpatient: P = 0.03 and P = 0.03, respectively).

Conclusion and clinical relevance
Owner-perceived pain decreased in all dogs, whether they were enrolled in formal in-clinic rehabilitation or not. This was attributed to customized interventions, including rehabilitation, pain management, and weight management. Our results corroborated reports that multimodal OA management plans, including rehabilitation interventions, ameliorate symptoms of OA in humans. Given the high prevalence of canine OA, this study supported the beneficial effects of multimodal rehabilitation interventions on the well-being of osteoarthritic dogs.

Background and objective
The proportion of companion animals requiring veterinary attention is on the rise and access to care is a growing concern. Accessibility is a multifactorial concept and is affected by cultural, sociodemographic, and financial considerations, including language spoken, place of residence, required travel distance to the nearest medical facility, and ability to pay for necessary medical care. This research focused on how accessibility is affected by service density through the identification of low- and high-density companion animal hospital clusters in the province of Ontario.

Procedure
Data based on Census Subdivision and Forward Sortation Area administrative boundaries from the 2021 Canadian census were combined with a repository of provincial general practice companion animal hospitals. Using the spatial scan statistic with a Poisson model, we identified spatial clusters of low and high companion animal hospital density, using households and population as denominators based on Census Subdivision and Forward Sortation Area boundaries.

Results
A low-density clinic cluster was consistently located in the Greater Toronto Area (i.e., a high-density urban population), despite the assumption that large urban centers are well serviced. The locations of high-density clinic clusters varied with choice of geographic boundary and population denominator. However, unlike low-density clusters, these were centered around smaller and/or more rural communities. Potential biases associated with the lack of available pet ownership-level data are referenced in the Discussion.

Conclusion and clinical relevance
The potential socioeconomic causes of these clusters and their One Health implications are important to consider when allocating additional resources for veterinary care in these populations.

Objectives, animals, and procedure
The main objective of this study was to evaluate whether, in canine soft tissue sarcoma, planned surgical lateral margins of a minimum 2 cm versus a minimum 3 cm yield complete histologic (tumor-free) margins with the same frequency. A secondary aim was to evaluate if planned narrow margins of 1 to 1.5-centimeter lateral margins with 1 fascial plane deep can produce an acceptable rate of complete surgical excision.

Results
Of tumors that were sampled preoperatively, biopsies were obtained in 14/30 (46.6%) of cases; 85% of these were accurate in diagnosing tumor grade. Of the 31 total tumors included in this study, there was complete resection in 7/8, or 88% (95% CI: 79%, 92%), with a 1 to 1.5-centimeter lateral margin; 10/11, or 91% (95% CI: 85%, 94%), with a 2 to 2.5-centimeter margin; and 11/12, or 92% (95% CI: 86%, 95%), with a 3-centimeter margin. All 3 incompletely resected tumors were grade 1.

Conclusion and clinical relevance
Although statistical significance was not demonstrated due to a small sample size, the results of this study suggest clinical importance, with comparable rates of resection among these groups.

Calcium is essential for neuromuscular signaling, cardiovascular stability, and metabolic regulation. Disturbances in calcium homeostasis can exacerbate critical illness in small animal patients, whereas more profound abnormalities are associated with life-threatening complications. Although not frequently encountered, both hypocalcemia and hypercalcemia require rapid recognition and targeted therapy in an emergency setting. This article reviews the fundamental principles of calcium regulation, outlines the major etiologies and clinical features of disordered calcium balance, and provides an evidence-based approach to acute management. Practical considerations for monitoring, fluid and drug therapy, and supportive care are emphasized. Finally, we present novel and experimental interventions under evaluation in both veterinary and human medicine, highlighting areas in which future research may improve treatment options for animals.

A 12-year-old thoroughbred mare was presented with colic and diarrhea. Clinical examination revealed mild tachycardia with injected mucous membranes. Abdominal ultrasonography identified thickened colon walls, an irregular, mottled liver, and free fluid. The mare had elevated liver enzymes and electrolyte abnormalities that continued to worsen during hospitalization and included hypoalbuminemia. Despite intensive and varied medical treatments, the mare’s condition deteriorated and she was humanely euthanized. Postmortem examination revealed a large adenocarcinoma with osseous metaplasia in the right dorsal colon and mesocolon with multifocal metastasis.