A 56-year-old female patient undergoes a screening colonoscopy, which detects a single 9-mm sessile polyp that is removed completely using a hot snare. Eight hours after the procedure, the patient presents to the emergency department with abdominal pain. On examination, she has a temperature of 97.8° F a blood pressure of 110/63 mmHg, and a heart rate of 110 beats per minute. She has no evidence of peritonitis and denies blood per anorectum. Her laboratory results show a hemoglobin of 7 g/dL with a normal white blood cell count; her abdominal plain films show no pneumoperitoneum. The most likely cause of this presentation is