Reassigned surgical margins after neoadjuvant chemotherapy results in low local recurrence in dogs with mast cell tumours.

BACKGROUND: Neoadjuvant chemotherapy (NAC) is delivered before surgery to allow less extensive tumour resection, but the optimal surgical margin width after NAC is unknown. The aim of this study was to determine the impact of reassigned margins on local recurrence after NAC in dogs with mast cell tumours (MCTs). METHODS: A retrospective analysis was conducted for dogs with MCTs undergoing NAC consisting of vinblastine and prednisolone, subsequent tumour resection and lymphadenectomy, and a minimum follow-up of 6 months. Surgical margins were reassigned based on the size of the MCT after NAC. Pre- and post-NAC measurements of MCTs were recorded. The margin status was assessed with a combined radial and tangential sectioning technique; pre-NAC MCT cytograde and lymph node (LN) cytological status were compared with the Kiupel grade and Weishaar stage, respectively. RESULTS: Twenty-two dogs were included. MCT shrinkage after NAC consistently occurred, with a median reduction rate of 40.4% (range 5%-94.5%). Margins were complete in 15 of 22 dogs, and two MCTs and three LNs appeared histologically downgraded and downstaged, respectively. Two (9.1%) MCTs recurred. LIMITATIONS: The limitations of this study were the small sample size and relatively short follow-up. CONCLUSION: NAC leads to shrinkage of canine MCTs, with the resulting reassigned surgical margins being associated with a low recurrence rate.

Laparotomy-assisted endoscopic removal of gastrointestinal foreign bodies: Evaluation of this technique and postoperative recovery in dogs and cats.

OBJECTIVE: To compare the outcome of the laparotomy-assisted endoscopic removal (LAER) of gastrointestinal foreign bodies (FBs) with traditional enterotomy, and to determine which factors affected the ability to remove FBs. STUDY DESIGN: Retrospective observational study. SAMPLE POPULATION: Dogs and cats (n = 81) with gastrointestinal FBs. METHODS: Dogs and cats were divided into Group 1 (LAER, n = 40) and Group 2 (Enterotomy, n = 41). The localization and characteristics of the FBs (sharp or blunt; discrete or linear; single or multiple) were evaluated statistically to identify the factors that affected the ability of LAER to remove, partially or completely, the FBs (χ2 test). The length of the postoperative stay, postoperative analgesia, and resumption of spontaneous feeding were compared between groups (Mann-Whitney U-test). Short-term follow up (14 days) was recorded. RESULTS: Laparotomy-assisted endoscopic removal allowed complete or partial removal of FBs in 35/40 dogs and cats, regardless of the characteristics or the localization of the FBs. The presence of intestinal wall damage (p = .043) was associated with the conversion to an enterotomy. Group 1 required a shorter postoperative hospital stay (p = .006), less need for analgesia (p < .001), and experienced a faster resumption of spontaneous feeding (p = .012), and similar complication rate to Group 2. CONCLUSION: Laparotomy-assisted endoscopic removal resulted in a faster postoperative recovery when compared with an enterotomy. The FBs' characteristics or localization did not affect the efficacy of the technique to remove FBs. CLINICAL SIGNIFICANCE: Laparotomy-assisted endoscopic removal allows the removal of a variety of FBs, avoiding intestinal incision and resulting in a fast postoperative recovery.

The 2-tier grading system identifies canine cutaneous and/or subcutaneous mast cell tumors with aggressive biological behavior regardless of growth model.

Histologic grading of canine cutaneous mast cell tumors (cMCTs) has prognostic and therapeutic implications, yet validation for subcutaneous MCTs (scMCTs) is lacking. For scMCTs with or without dermal invasion, determining their biological behavior remains poorly standardized and sometimes sparks controversy. This prospective study aimed to assess the prognostic utility of the 2-tier histologic grading system in MCTs with different growth models (GMs) and explore the prognostic impact of the GM itself. We assessed 6 histologic GM categories: solely cMCT (C-SC0), cMCT with superficial (C-SC1) or deep subcutaneous (C-SC2) involvement, solely scMCT (SC-C0), and scMCT with deep (SC-C1) or superficial (SC-C2) infiltration of the dermis. Ninety-one MCTs from 76 dogs undergoing excision and regional/sentinel lymphadenectomy were examined. GM classification identified 11 (12%) C-SC0 tumors, 12 (13%) C-SC1, 15 (16%) C-SC2, 21 (23%) SC-C0, 15 (16%) SC-C1, and 17 (19%) SC-C2. Mitotic count, 2-tier grade, nodal involvement, surgical margins, and outcome were stratified according to GM. scMCTs lacking dermal invasion, historically associated with a benign clinical course, had a poor prognosis in 10% of cases. cMCTs exhibiting deep subcutaneous involvement included the largest percentage of high-grade tumors (33%), had the highest occurrence of overt nodal metastases (33%), and had the lowest 1-year survival rate (86%). Histologic grade was confirmed as a relevant prognostic factor, surpassing nodal involvement and histologic margin status. The 2-tier histologic grading enabled the identification of all MCTs with aggressive biological behavior, regardless of their cutaneous or subcutaneous location.

Retrospective evaluation of a hand-sewn side-to-side intestinal anastomosis technique in dogs and cats.

Background: Hand-sewn intestinal resection and anastomosis are commonly performed in veterinary medicine. The outcome of the hand-sewn side-to-side anastomosis (SSA) technique has never been described and compared to other techniques in dogs and cats. Aim: The study aims to describe the side-to-side hand-sewn anastomosis technique in small animals and to compare it with the end-to-end technique. Methods: A retrospective evaluation of the clinical records of dogs and cats that underwent enterectomy between 2000 and 2020 and were treated with side-to-side or end-to-end anastomosis (EEA) was performed. Results: Of the 52 dogs and 16 cats included in the study, 19 dogs and 6 cats received an SSA, and the remaining received an EEA. No intraoperative complication was reported. However, short-term complication rates were comparable, and mortality rates in the EEA group were higher. At the same time, stenosis was a frequent complication of SSA and was never reported following EEA. Conclusion: End-to-end technique remains the gold standard for hand-sewn intestinal anastomosis in small animals. However, SSA can be considered for selected cases with acceptable morbidity and mortality rates.

Perforated duodenal ulcer in a dog with gallbladder agenesis.

Background: Duodenal ulceration (DU) in dogs derives from different causes but has never previously been related to gallbladder agenesis (GA). GA is a rare congenital disorder in dogs and is considered a predisposing factor for DU in humans. Case Description: A 5-month-old intact female Maltese was presented for acute vomiting and diarrhea. Abdominal ultrasound suggested duodenal perforation and absence of the gallbladder. Exploratory laparotomy was performed to treat the perforation and confirmed GA. Hepatic ductal plate malformation (DPM) was histologically diagnosed in liver biopsy, but no signs of liver dysfunction were detected by blood work at first admission. Two months later, the dog developed signs of portal hypertension and medical treatment was started. However, the clinical condition gradually worsened until liver failure and the dog was euthanized 8 months after surgery. Necropsy confirmed hepatic abnormalities. Conclusion: This report describes a case of DU associated with GA and DPM in a dog. As in humans, GA may represent a hepatobiliary disease predisposing to gastroduodenal ulcerations.