An 11-year old mixed breed spayed dog was presented to the Cornell University Hospital for Animals (CUHA) Soft Tissue Surgery Service on 1/28/14 with a history of a mass in the colon found on palpation by her primary veterinarian. This mass was first detected in September, 2013 and had rapidly grown in size. Additionally, the patient had a two week history of coughing , as well as a chronic history of mild bilateral hind limb lameness. Most importantly, the patient was unable to defecate other than a small amount of yellow fluid, with great effort (tenesmus) for the previous two weeks. The patient was started on oral lactulose three days prior to presentation at CUHA, with no improvement.