Surgical Management of Colonic Adenocarcinoma in a Rat (Rattus norvegicus)

A 9-month-old female Dumbo rat (Rattus norvegicus) was evaluated for a 24-hour history of obstipation. A general physical examination revealed a large irregular abdominal mass, extending caudally from mid-abdomen to the pelvis. The mass had a firm central region with a compressible periphery. Radiographic imaging confirmed severe intestinal distention, but failed to delineate a discrete mass. Following 3 days of unsuccessful medical therapy for possible colonic impaction, surgical intervention was elected. A colocolic resection and anastomosis was completed to remove 7 cm of the colon, including the 5 cm mass and 1 cm of grossly normal appearing colon proximal and distal to the mass. Histology confirmed colonic adenocarcinoma. The rat lived for 2 years, following colonic resection and anastomosis, uncomplicated by gastrointestinal neoplasia or metastatic disease and was euthanized due to unrelated quality of life issues. Necropsy revealed no evidence of colonic tumor recurrence or metastatic disease.