Table of Contents and Abstracts

A 14-year-old spayed female Siamese cat was presented with signs consistent with a rapidly progressive cranial polyneuropathy. Magnetic resonance imaging of the brain revealed an extra-axial mass at the calvarial floor, extending caudally to involve bilateral trigeminal nerves and rostrally to involve the pituitary gland and optic chiasm. Additional findings included contrast-enhancing content within the bilateral tympanic bullae, mild mandibular and medial retropharyngeal lymphadenopathy, and a left tonsillar mass. Cytologic and histopathologic findings confirmed tonsillar lymphoma. The concurrent intracranial mass and the middle ear content were presumed to represent the same disease process, but the diagnosis was not confirmed. Oral glucocorticoid and lomustine were effective in resolving the dropped jaw and facial hypoesthesia. Neurogenic dry eye and corneal hypoesthesia also improved gradually, leading to complete resolution of secondary bilateral corneal ulcers by 20 wk after initiation of the oral chemotherapy. The cat remained in clinical remission throughout this period and survived for 166 d after the diagnosis. This is the first report of tonsillar lymphoma without oropharyngeal clinical signs in a cat presented with signs suggestive of concurrent intracranial involvement, leading to a rapidly progressive bilateral cranial polyneuropathy.

Key clinical message:
Lymphoma should be considered as an important differential diagnosis in cats with cranial polyneuropathy. Feline tonsillar lymphoma can exhibit concurrent central nervous system involvement without detectable disease in other organs.

Surgical management of feline idiopathic chylothorax remains unpredictable, with reported success rates varying widely despite combined procedures. We report a case of refractory idiopathic chylothorax in a cat that was successfully managed through a strategic, sequential surgical approach guided by indocyanine green (ICG) fluorescence. Initially, the cat underwent thoracoscopic thoracic duct occlusion (TDO) via clipping, but chylous effusion persisted. A 2nd surgery was conducted to achieve definitive thoracic duct ligation using sutures combined with additional clipping, yet the effusion remained refractory. Computed tomography after the 2nd surgery revealed a focal convergence of lymphatic vessels within the abdominal cavity. Based on this, a 3rd intervention was undertaken, combining thoracoscopic TDO with laparoscopic intra-abdominal lymphatic vessel occlusion and a cisterna chyli incision. Real-time ICG fluorescence imaging allowed precise identification and addressing of complex lymphatic collaterals. Chylothorax completely resolved ~1 mo after this 3rd surgery. The cat remained complication-free with no recurrence for 324 d after surgery. This case demonstrated the efficacy of a multimodal, sequential strategy for refractory feline chylothorax, integrating computed tomography-based diagnostic evaluation with combined thoracoscopic and laparoscopic lymphatic interventions. This comprehensive, minimally invasive approach, enhanced by real-time ICG visualization, offers a potent therapeutic option when conventional, single-cavity treatments fail.

Key clinical message:
This report describes for the first time a sequential and minimally invasive surgical approach to treat feline idiopathic chylothorax, by combining completely endoscopic (thoracoscopic and laparoscopic), ICG-guided TDO, intra-abdominal lymphatic vessel occlusion, and cisterna chyli incision. Moreover, this case showed that ICG can be effectively and noninvasively administered to the paw pads, obviating the need for invasive abdominal surgery.

A 5-week-old male golden retriever puppy was presented with multiple, rapidly progressive skin masses. One of the masses had been present since birth; the duration of the other 2 masses was unknown. Fine-needle aspiration cytology of the lesions revealed a monomorphic population of round cells, raising suspicion for a round cell neoplasm. Two representative masses were submitted for histologic examination and immunohistochemical analysis. Histologically, the neoplasm was composed of dense, non-epitheliotropic infiltrates of atypical lymphoid cells within the dermis and subcutis. Immunophenotyping confirmed a T-cell origin, establishing a diagnosis of non-epitheliotropic cutaneous T-cell lymphoma. In the postoperative period, the puppy’s health declined and humane euthanasia was elected. A postmortem examination did not occur, precluding assessment for systemic involvement. To the authors’ knowledge this is the first case of non-epitheliotropic cutaneous T-cell lymphoma in a dog of this age documented in the veterinary literature. This report underscores the importance of including cutaneous lymphoma in the differential diagnosis of rapidly progressive skin masses in a dog, irrespective of age, and highlights the utility of histopathology and immunohistochemistry for achieving a diagnosis.

Key clinical message:
Lymphoma can occur in dogs of any age and should not be excluded as a differential diagnosis, even in very young puppies.

A young French bulldog was presented with persistent hemorrhagic diarrhea and suspected rectal stricture unresponsive to previous medical management. Comprehensive diagnostic tests, including blood work, colonoscopy, biopsy, antimicrobial susceptibility testing, and fluorescence in situ hybridization analysis, confirmed granulomatous colitis with invasive Escherichia coli. Culture testing identified a multidrug-resistant strain susceptible to meropenem. Concurrently, a rectal stricture was confirmed and managed with 3 repeat endoscopic balloon dilations. Systemic improvement was noted mid-treatment, and the stricture resolved at subsequent follow-up.

Key clinical message:
This case report highlights the successful diagnosis and management of multidrug-resistant granulomatous colitis in a French bulldog, including the use of meropenem for targeted antimicrobial therapy and repeat endoscopic balloon dilations for rectal stricture resolution. It underscores the importance of accurate diagnosis, appropriate antimicrobial selection, and structural intervention in the management of complex cases.

Primary laryngeal tumors are rare in dogs and may cause severe airway obstruction. Euthanasia is frequently elected because of the severity of clinical signs and the challenges associated with surgical treatment. A 3-year-old spayed female Italian greyhound dog was referred because of recurrence of a laryngeal rhabdomyosarcoma following incomplete surgical removal of a laryngeal mass. Residual tumor progression was identified 15 d after surgery and the dog was referred for further evaluation. Computed tomography revealed a soft-tissue mass within the right laryngopharyngeal wall, showing central contrast enhancement. The owner declined additional aggressive surgery and radiation therapy was delivered. A total radiation dose of 24 Gy was delivered in 4 weekly fractions. Clinical signs improved following treatment and tumor reduction was observed 168 d after initiation of radiation therapy. The dog remained clinically stable with sustained tumor reduction at the last follow-up, 742 d after initiation of radiation therapy. This case suggests that limited surgical management followed by radiation therapy may represent a viable treatment option and may lead to favorable long-term clinical outcomes in dogs with laryngeal rhabdomyosarcoma.

Key clinical message:
Limited surgical removal followed by radiation therapy may represent a treatment option for dogs with laryngeal rhabdomyosarcoma.

This report describes a rare case of bilateral congenital aphakia with anterior segment malformation in a 12-week-old male cocker spaniel puppy. The puppy was initially suspected of having glaucoma and was subsequently diagnosed with anterior segment dysgenesis and aphakia resulting in blindness. Ophthalmic examination showed corneal opacity, absence of pupillary openings, and negative pupillary light reflexes. B-mode and high-frequency ultrasonography showed absence of the lens, poorly defined anterior chambers, and hyperechoic tissue adherent to the cornea, consistent with anterior segment dysgenesis. Unlike in similar cases in other species, enucleation was not indicated due to ocular stability and absence of discomfort. The puppy demonstrated functional adaptation to blindness and remained under close ophthalmic monitoring. This case underscores the diagnostic value of ultrasonography in identifying congenital aphakia and associated anterior segment abnormalities in dogs, facilitating early diagnosis and management.

Key clinical message:
Congenital aphakia is a rare developmental ocular abnormality that may occur with other anterior segment defects. Ocular ultrasonography is a valuable, noninvasive, diagnostic tool for evaluating intraocular structures when direct intraocular examination is not possible.

This case report describes the occurrence of soft tissue sarcoma at the surgical site of partial tarsal arthrodesis in 2 dogs within 8 mo after surgery. Surgical correction was uncomplicated in both cases, and the dogs did clinically well postoperatively, until masses were noted over the surgical sites. Each dog underwent amputation of the affected leg, as the masses were deemed unresectable. This report describes an uncommon potential complication of partial tarsal arthrodesis in dogs.

Key clinical message:
The cases reported herein are apparently the first descriptions of soft tissue sarcoma as a possible surgical complication related to partial tarsal arthrodesis in the dog. They highlight soft tissue sarcoma as a differential diagnosis to consider for surgical site swellings of the tarsus; however, further studies are needed to confirm these findings.

Objectives
Antimicrobial resistance (AMR) is a serious threat to human and animal health; the emergence of 3rd-generation cephalosporin- and fluoroquinolone-resistant Enterobacterales is particularly problematic. Because Escherichia coli is the most common cause of urinary tract infections in dogs, AMR has real-world impact. The objectives of this study were to evaluate the antimicrobial susceptibility of canine urinary isolates of E. coli and to determine if AMR is increasing in Saskatchewan.

Animals and procedure
A total of 576 diagnostic isolates of canine urinary E. coli from individual dogs were grown by Prairie Diagnostic Services (Saskatoon, Saskatchewan). Antimicrobial minimum inhibitory concentrations (MICs) were determined via broth microdilution and agar dilution. Strains of E. coli resistant to the β-lactams and nalidixic acid were screened for broad-spectrum β-lactamases and plasmid-mediated quinolone resistance genes via PCR. Changes in the annual frequency of resistance and median MIC were evaluated using generalized linear models.

Results
Most (76.9%) isolates were pan-susceptible, whereas only 4.3% were multidrug resistant. Ampicillin resistance was most common (13.9%), though resistance to other agents occurred infrequently (≤ 10%). Only 2.7% and 1.2% of isolates possessed CMY-2- or CTX-M-type β-lactamases, respectively. Plasmid-mediated quinolone resistance genes were present in < 1% of isolates. Although the frequency of categorical resistance did not rise significantly, the median annual ampicillin, nalidixic acid, and chloramphenicol MICs increased significantly.

Conclusion and clinical relevance
Antimicrobial resistance among canine urinary E. coli is not yet common in our region. The findings support the continued use of 1st-line therapies recommended by the International Society for Companion Animal Infectious Diseases.

Objective
Our objectives were first to compare inflammatory biomarkers in feedlot calves classified as apparently healthy controls or suspected bovine respiratory disease (BRD) cases; second, to validate a dried-blood spot-card device for storage and subsequent measurement of haptoglobin (Hp); and last, to determine whether Hp concentration was associated with subsequent treatment, re-treatment, and mortality outcomes.

Animals and procedure
Feedlot calves (n = 403) aged 8 to 10 mo were enrolled over a 3-month interval in fall of 2024. In an initial pilot study, serum concentrations of Hp, neopterin, and procalcitonin were measured using bovine-specific ELISAs in calves (n = 58) considered controls or BRD cases, based on visual assessment and rectal temperature. In the field study, 403 calves classified as apparently healthy controls or suspected BRD cases at the feedlot treatment area were sampled using a dried-blood spot-card methodology and Hp concentration was compared to subsequent treatment, relapse, and mortality outcomes.

Results
In the pilot study, all 3 biomarkers were higher in BRD cases than in controls, with Hp having the greatest between-group separation. In the field trial, dried-blood spot measurements of Hp correlated with paired serum Hp (rp = 0.804, P < 0.001). The Hp concentrations were lower in controls [28.5 ± 45.6 µg/mL (mean ± SD)] and untreated suspect cases (89.0 ± 72.2 µg/mL) than in calves treated for pneumonia (146.5 ± 75.1 µg/mL) and were higher still in calves that later relapsed (190.4 ± 89.5 µg/mL) or died (199.1 ± 99.5 µg/mL). The Hp discriminated calves that later died from survivors (AUC = 0.72, 95% CI: 0.63 to 0.81), whereas rectal temperature did not (AUC = 0.44, 95% CI: 0.34 to 0.53).

Conclusion and clinical relevance
Haptoglobin concentration appeared to be a promising adjunct biomarker for risk stratification of feedlot calves with suspected BRD. Thresholds identified in this observational study could facilitate targeted interventions using pen-side monitoring.

A 3-year-old quarter horse cross mare was presented to the Atlantic Veterinary College (Charlottetown, Prince Edward Island) for evaluation of a persistent draining tract on the ventral aspect of the left mandible, associated with a previous fracture. Radiography and ultrasonography confirmed the presence of a chronic sequestrum separated from the parent bone. Sequestrectomy and surgical debridement of the mandible were carried out, and the horse was discharged. Three months later, the mare was presented again to the Atlantic Veterinary College, as the draining tract had not resolved. A CT scan of the mare’s skull revealed infection of Tooth 310. The tooth was surgically removed. The animal was discharged, and clinical signs were resolved at the 1-month recheck examination.

Key clinical message:
The importance of CT in diagnosing tooth involvement secondary to a mandibular fracture is described. In addition, the growing prevalence of antibiotic resistance to trimethoprim-sulfamethoxazole due to prolonged use and frequent usage in equine practice is highlighted.