This paper reports on a 55-year-old woman presenting with left lower quadrant and groin pain that posed a significant diagnostic challenge. She had a history of obesity and stage 1B endometrial carcinoma treated with surgery and radiation 1-year prior. Despite several unsuccessful biopsy attempts and unclear imaging findings, she was ultimately diagnosed with a pelvic sidewall abscess secondary to a bowel microperforation, a rare late complication of radiation related to adhesions, weakened bowel, and peristalsis. Her condition was successfully treated with drainage and antibiotics. It is widely known that patients with endometrial cancer and comorbid obesity often experience diagnostic delay, weight stigma, and other barriers and thus deserve careful attention and continued advocacy.