A 53-year-old woman had abdominal pain, nausea, vomiting, and obstipation for 4 days. Her medical history was significant for bipolar disorder, schizophrenia, total abdominal hysterectomy after a complicated birth, and right oophorectomy for a hemorrhagic cyst. She was being followed up by the gynecology service as an outpatient for a left adnexal mass and was on their elective operative schedule for resection for a presumed ovarian malignant neoplasm. On examination, she had abdominal distention and was tender to palpation in the left lower quadrant. Her laboratory analysis findings, including a complete blood cell count and metabolic panel, were normal aside from elevated levels of CA 19-9 (35 U/mL), carcinoembryonic antigen (58.3 ng/mL; to convert to micrograms per liter, multiply by 1.0), and cancer antigen 125 (62 U/mL; to convert to kilounits per liter, multiply by 1.0). A computed tomographic scan of the abdomen revealed a complex cystic and solid pelvic mass measuring 13 × 15 cm, diffuse retroperitoneal lymphadenopathy, and cecal distention with a pedunculated area of mural enhancement in the transverse colon measuring 2 cm but no obvious obstructing colonic mass (Figure 1 and Figure 2). The gastroenterology service was consulted and declined to perform colonoscopy owing to a presumed inability to prepare the bowel.