T-cell lymphoma involving the rectum of a dog.

A mediastinal mass was diagnosed in a 7-year-4-month-old neutered female mixed breed dog following a 3-week history of lethargy, hyporexia and pyrexia. Bi-cavitary imaging, needle aspirate cytology and flow cytometry confirmed WHO clinical stage IVb, intermediate to large T-cell lymphoma involving the mediastinum, liver and spleen. The dog initially responded to a multidrug chemotherapy protocol but clinical deterioration occurred 3 months later. The dog presented with anorexia, vomiting and diarrhoea, associated with marked faecal tenesmus and haematochezia, initially believed by the primary care practitioner to be related to chemotherapy toxicity. However, rectal examination revealed multiple sessile and pedunculated masses. Further diagnostic imaging, cytology and flow cytometry confirmed progressive disease, including T-cell lymphoma of the rectum. Histology and immunohistochemistry confirmed an infiltrate of intermediate-sized CD3-positive neoplastic cells that expanded the rectal mucosa. Rectal lymphoma is uncommon in dogs and previous cases have been B cell in origin. In this report we describe the clinical presentation and macro- and microscopic findings of a case of canine T-cell lymphoma involving the rectum.

Effect of pituitary-dependent hypercortisolism on the survival of dogs treated with radiotherapy for pituitary macroadenomas.

BACKGROUND: Radiotherapy (RT) is an effective treatment for dogs presented with neurologic signs caused by pituitary tumors. However, its impact on the outcome of concurrent pituitary-dependent hypercortisolism (PDH) is controversial. OBJECTIVES: Determine whether dogs with PDH have longer survival after pituitary RT compared with dogs with nonhormonally active pituitary masses and to evaluate whether clinical, imaging, and RT variables affect survival. ANIMALS: Ninety-four dogs divided into 2 groups: PDH and non-PDH, based on the presence of hypercortisolism. Forty-seven dogs were allocated to the PDH group and 47 to the non-PDH group. METHODS: Retrospective cohort study in which clinical records of dogs undergoing RT for pituitary macroadenomas between 2008 and 2018 at 5 referral centers were retrospectively evaluated. RESULTS: Survival was not statistically different between PDH and non-PDH groups (median survival time [MST], 590 days; 95% confidence interval [CI], 0-830 days and 738 days; 95% CI, 373-1103 days, respectively; P = .4). A definitive RT protocol was statistically associated with longer survival compared with a palliative protocol (MST 605 vs 262 days, P = .05). The only factor statistically associated with survival from multivariate Cox proportional hazard analysis was total radiation dose (Gy) delivered (P < .01). CONCLUSIONS AND CLINICAL IMPORTANCE: No statistical difference in survival was identified between the PDH and non-PDH groups, and longer survival was associated with higher Gy delivered.

Patterns of nodal metastases, biological behaviour and prognosis of canine mast cell tumours of the pinna: A multi-institutional retrospective study.

Canine cutaneous mast cell tumours (cMCTs) of the pinna have been associated with an aggressive biological behaviour, although data remain scarce. The knowledge acquired over the past years on histologic gradings, and the value of lymph node (LN) staging, may help in better characterizing this anatomical presentation. The first aim was to describe the frequency, location, and histologic appearance of LN metastases in cMCT of the pinna. A second aim was to evaluate prognosis. Medical records of dogs with cMCT of the pinna, that underwent tumour and sentinel (SLN) or regional LN (RLN) excision, were reviewed. The influence of potential prognostic variables on time to progression (TTP) and tumour-specific survival (TSS) was investigated. Thirty-nine dogs were included: 19 (48.7%) had Kiupel high-grade (K-HG) and 20 (51.3%) had low-grade (K-LG) MCTs. Eighteen (46.1%) dogs underwent SLN mapping: the superficial cervical LN was at least one of SLN in 17 (94.4%) cases. Twenty-two (56.4%) dogs had LN metastases; the superficial cervical LN was always involved. On multivariable analysis, only K-HG was associated with increased risk of progression (p = .043) and tumour-related death (p = .021). Median TTP and TSS were 270 and 370 days in K-HG, respectively; these were not reached in dogs with K-LG tumours (p < .01). cMCTs of the pinna are often K-HG and are also associated with a higher frequency of LN metastasis; however, we confirmed the independent prognostic value of histologic grading. A multimodal treatment may lead to favourable long-term outcome. Moreover, the superficial cervical LN is most often the SLN.

Serum amyloid A and other clinicopathological variables in cats with intermediate- and large-cell lymphoma.

OBJECTIVES: Serum amyloid A (SAA) concentrations are increased in cats with lymphoma vs healthy cats; however, the association between SAA concentrations and prognosis in cats with lymphoma is unclear. The aim of this study was to evaluate if SAA concentrations were different in cats with nasal vs non-nasal lymphoma, if SAA concentrations are prognostic in patients treated with high-dose chemotherapy and if SAA concentrations are correlated with other clinicopathological variables. METHODS: Cats diagnosed with intermediate- or large-cell lymphoma between 2012 and 2022 with SAA concentration data available were included. Associations between tumour site (nasal vs non-nasal), stage, response to treatment and SAA concentration were evaluated using non-parametric statistics. Associations between SAA concentrations and stage with survival time were evaluated using Cox regression analysis. Patients with nasal tumours and those not receiving high-dose chemotherapy were excluded from the survival analyses. RESULTS: Thirty-nine cats were included. Median SAA concentrations were significantly higher in non-nasal compared with nasal lymphoma (42 µg/ml [range <0.3-797] vs <0.3 µg/ml [range <0.3-0.9]; P = 0.026). SAA concentrations did not correlate with tumour stage. Median survival time for patients with non-nasal tumour and undergoing chemotherapy was 49 days (range 2-1726). Responders had a better median survival time than non-responders (273 days [range 43-1728] vs 39 days [range 2-169]; P <0.001), whereas SAA concentrations were not associated with survival time. Lower haematocrit at presentation was associated with a reduced median survival time (P = 0.007). CONCLUSIONS AND RELEVANCE: In the population examined, no correlation between serum concentration of SAA and prognosis in patients with lymphoma was identified, while low haematocrit and lack of response to treatment were both found to be associated with survival time. SAA concentrations were elevated in patients with non-nasal lymphoma vs patients with tumours confined to the nasal cavity.

Multimodal Treatment of a Canine Lingual Melanoma Using a Combination of Immunotherapy and a Tyrosine Kinase Inhibitors.

A 9-year-old female neutered Miniature Schnauzer was diagnosed with a lingual malignant melanoma on the basis of incisional biopsy and histopathology. The patient was initially given a guarded prognosis of a few months' survival as surgical treatment options were declined by the owner. In order to control the disease a combination treatment of immunotherapy and tyrosine kinase inhibitors was initiated. The mass showed a marked and sustained reduction in size, whilst preserving quality of life for the patient, with a survival at the time of writing of 15 months since diagnosis. This experience suggests that combination therapy for oral malignant melanoma using immunotherapy and tyrosine kinase inhibitors may be successful in some patients and warrants further investigation.

Urinary incontinence secondary to a suspected congenital urethral deformity in a kitten.

CASE SUMMARY: A 5-month-old entire male domestic shorthair kitten was referred for investigation of a month-long history of urinary incontinence. Clinical examination, baseline blood work and imaging (plain radiography and ultrasonography) were unremarkable. Urinalysis documented a urinary tract infection and a retrograde urethrocystogram revealed an outpouching of the pelvic urethra. Surgical exploration revealed the absence of the dorsal portion of the urethral wall in this section of pelvic urethra, replaced by an epithelial lined expanded 'pouch'. The ventral aspect of the urethra appeared grossly normal. A modified perineal urethrostomy was performed to create an anastomosis of the urethral pouch to the skin of the perineum alongside conventional castration. The kitten made a full recovery and the incontinence resolved within 48 h. A congenital urethral diverticulum and secondary urinary tract infection were deemed the most likely aetiology in this case. RELEVANCE AND NOVEL INFORMATION: Urethral diverticuli are a rare condition in veterinary medicine. To our knowledge, it has only been reported in two dogs and presumptively in one cat, all of which made a complete recovery after surgical intervention. The present case reports an unusual urethral deformity as a potential differential diagnosis for lower urinary tract signs in a young cat.

Obstructive pancreatolithiasis in a cat with triaditis and concurrent hypercalcaemia.

CASE SUMMARY: A 7-year-old neutered female domestic longhair cat was presented for further investigation of suspected hepatobiliary disease. Increases in serum 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester lipase and hepatobiliary enzymes, with concurrent hypoalbuminaemia, were documented on blood biochemistry. Abdominal ultrasonography findings were consistent with acute pancreatitis with multiple pancreatoliths visualised within the pancreatic duct. Treatment for suspected triaditis was initiated with a hydrolysed protein diet, amoxicillin-clavulanate, hepatoprotectants and buprenorphine. Fifty-three days later, the patient presented with hypercalcaemia and obstructive pancreatolithiasis, and was euthanased. Post-mortem examination revealed severe chronic active pancreatitis with moderate chronic lymphocytic, plasmacytic cholangiohepatitis and mild chronic lymphocytic-plasmacytic duodenal enteritis (triaditis). Multiple calcium carbonate pancreatoliths present within the pancreatic ducts had resulted in pancreatic duct obstruction. RELEVANCE AND NOVEL INFORMATION: Pancreatolithiasis is a very rare condition in cats, with only five reports to date. In human medicine, pancreatolithiasis is often a sequala to chronic pancreatitis, seen in up to 50-90% of patients. However, in cats the aetiology of pancreatolithiasis, and indeed chronic pancreatitis, is poorly understood. This report describes a case of obstructive pancreatolithiasis in a cat with histopathological confirmation of triaditis and is the first report of hypercalcaemia in a cat with obstructive pancreatolithiasis. This further adds to the evidence base that pancreatolithiasis may have a similar pathogenesis to humans and can develop secondarily to chronic pancreatitis in cats.

Lipoxygenase-5 Expression in Canine Urinary Bladder: Normal Urothelium, Cystitis and Transitional Cell Carcinoma.

Transitional cell carcinoma (TCC) is the most common canine urinary tract tumour and mimics human invasive TCC. Human TCCs overexpress lipoxygenase (LOX)-5 and the use of target inhibitors has proven effective in inhibiting neoplastic growth. In this study, we investigated the immunohistochemical expression of LOX-5 in normal canine urinary bladder, cystitis and TCC. The comparative expression of LOX-5, cyclo-oxygenase (COX)-1 and COX-2 among the three tissue groups was also examined. Biopsy samples from cases of cystitis and TCC were reviewed from 2012 to 2016; samples of histologically normal bladder were used as controls. Dogs were excluded if they had received glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs) and/or chemotherapy prior to tissue collection. LOX-5 was expressed in 95% of TCCs, 23% of cases of cystitis and 10% of controls. LOX-5 and COX-2 immunohistochemistry scores were significantly (P <0.01) higher in TCCs versus cystitis and normal bladders. Results of this study support the rationale for further investigation of the use of NSAIDs with dual anti COX-2 and LOX-5 effect for the treatment of canine TCC.