A 56-year-old man with a history of prostate cancer presented to the emergency department (ED) for abdominal pain, vomiting, and tenesmus. Four days before the presentation, he had undergone robotic radical prostatectomy. His examination was significant for diffuse abdominal tenderness without frank peritonitis. Although his vitals were initially normal, he became progressively more hypotensive despite fluid resuscitation and eventually required vasopressors. Laboratory evaluation revealed an anion gap metabolic lactic acidosis with a normal WBC count. Initial computed tomography of the abdomen and pelvis with intravenous contrast (Figure 1) showed mild nonspecific circumferential thickening of the distal rectum. Because of the patient’s clinical deterioration, he was sent for repeat computed tomography with rectal contrast (Figure 2), which revealed his diagnosis.Figure 2Computed tomography of the abdomen and pelvis with rectal contrast (axial view) showing rectal perforation, with the rectal contrast extending through a full-thickness defect at the 10 o’clock position of the lower rectum into the pelvis and peritoneal cavity.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Postoperative rectal perforation. The patient was treated with antibiotics and was immediately taken to the operating room for abdominal washout, which revealed 3 L of feculent material in the abdomen. He had a prolonged hospital stay and was discharged to a skilled nursing facility 1 month later. Postoperative rectal injury is a rare but known complication of robotic radical prostatectomy. Most cases are discovered and repaired during surgery. However, cases that are not diagnosed during surgery often have significant morbidity.1Wedmid A. Mendoza P. Sharma S. et al.Rectal injury during robot-assisted radical prostatectomy: incidence and management.J Urol. 2011; 186: 1928-1933Crossref PubMed Scopus (42) Google Scholar Therefore, a high index of suspicion is needed to diagnose postoperative rectal injuries, and it is one of the few instances when rectal contrast should be routinely considered.2Marres C.C.M. Engelmann E.W.M. Buskens C.J. et al.The importance of rectal contrast in CT assessment to detect anastomotic leakage after colorectal surgery.Colorectal Dis. 2021; 23: 2466-2471Crossref PubMed Scopus (2) Google Scholar Those cases identified in the ED will require admission and surgical consultation because their management requires bowel diversion with delayed fistula closure.