Mast cell tumours in dogs less than 12 months of age: a multi-institutional retrospective study.

OBJECTIVES: To describe the clinicopathological and genetic characteristics of mast cell tumours in dogs less than 12 months old. MATERIALS AND METHODS: Retrospective review of dogs aged less than 12 months when diagnosed with mast cell tumours at three referral hospitals in the UK. RESULTS: Sixteen pure-bred dogs were included, of which 11 were female. The median age at first presentation and diagnosis were 7.6 and 9 months, respectively. In 13 dogs the mast cell tumours were cutaneous and in three they were subcutaneous. Four cutaneous mast cell tumours were described as high-grade (Patnaik or Kiupel) and nine were Patnaik grade II; three had mitotic index of >5 in 10 high-power fields. Of the three subcutaneous tumours, two had an infiltrative growth pattern and one had mitotic index of 10 per 10 high-power fields. Of 10 tested dogs, seven had c-kit mutations in exon 11 and Ki-67 score was above the cut-off value in nine. Four of 12 cases showed evidence of metastasis in the regional lymph nodes. After varying treatment protocols, all patients were alive and disease free at a median of 1115 days after diagnosis. CLINICAL SIGNIFICANCE: The prognosis of mast cell tumours in dogs less than a year old appears better than the adult counterparts, even without extensive treatment.

Use of Oncept melanoma vaccine in 69 canine oral malignant melanomas in the UK.

OBJECTIVES: Oral malignant melanomas carry a poor-to-guarded prognosis because of their local invasiveness and high metastatic propensity. The Oncept melanoma vaccine is licensed to treat dogs with stage II or III locally-controlled oral malignant melanoma and this retrospective study aimed to assess survival of affected dogs treated with the vaccine in the UK. MATERIAL AND METHODS: Medical records of dogs with histopathologically-confirmed oral malignant melanoma that received the vaccine as part of their treatment were evaluated. Survival analyses for potential prognostic factors were performed. RESULTS: Sixty-nine dogs were included; 56 dogs, staged I to III, and with previous locoregional therapy, had a median survival time of 455 days (95% CI: 324 to 586 days). Based on Kaplan-Meier survival analysis with associated log-rank testing, no significant prognostic factors were identified for this population. Of the 13 patients with macroscopic disease treated with vaccine alone or in combination therapy, eight showed clinical response. Three patients with stage IV oral malignant melanoma survived 171, 178 and 288 days from diagnosis. CLINICAL SIGNIFICANCE: Patients treated with the melanoma vaccine in our study had survival times similar to their counterparts receiving the vaccine in the USA. There were observed responses in patients with macroscopic disease and so the vaccine could be considered as palliative treatment in dogs with stage IV disease.

Squamous cell carcinoma of the anal sacs in three dogs.

Anal sac squamous cell carcinoma is rare in dogs. Five cases have been previously reported, treatment of which involved surgery alone. This report describes three further cases of canine anal sac squamous cell carcinoma which underwent medical (meloxicam) management alone, resulting in survival of up to seven months. No metastases were identified. Squamous cell carcinoma, although extremely uncommon, should be considered as a possible differential diagnosis when a dog is presented for investigation of an anal sac mass.

Torsion of quadrate and right middle liver lobes and gallbladder in a German Shepherd dog.

BACKGROUND: An 11-year-old female German Shepherd was referred for assessment and management of a suspected liver tumour. Abdominal ultrasonography revealed abundant abdominal effusion and a right liver mass in continuity with a cystic structure. The dog had undergone splenectomy for a low-grade lymphoma 1 year prior. METHODS: Serum biochemical analysis revealed only a mild increase in alanine aminotransferase. The analysis of the free abdominal fluid showed a modified transudate. Ultrasound confirmed the presence of a hypoechoic lesion involving the right liver lobes, in addition to an over-distended gallbladder. Computed tomography examination demonstrated a massively dilated gallbladder and lower attenuation of the adjacent liver lobes, with no enhancement on quadrate and right middle liver lobes. The fine needle aspirate was compatible with a mixed subacute to chronic inflammation. Based on the investigational findings, an exploratory coeliotomy was performed. TREATMENT AND OUTCOME: The middle right and quadrate liver lobes and the gallbladder were rotated on their axes. The torsed lobes and the cystic duct were removed using a TA stapler without derotating the organs. Histopathological results were suggestive of infarction secondary to torsion of the lobes and gallbladder. The dog recovered from surgery without complications, and 20 months later was in good overall condition. CONCLUSION: Liver lobe torsion is an uncommon condition that rarely affects the right lobes. Gallbladder torsion is even more uncommon. To our knowledge, this is the first recorded case of quadrate and right middle liver lobe and gallbladder torsion.