A 36-year-old female presented to our gynecology clinic with a two-week history of persistent lower abdominal pain. She had undergone a cesarean section 10 years ago on her request and experienced persistent postmenstrual spotting for one year. Physical examination revealed a tender uterus. Laboratory studies revealed a white cell count of 14,300/mm³ and a C-reactive protein level of 11.3 mg/L. Pelvic ultrasonography revealed a cystic mass in the lower segment of the uterus (Figure 1). Furthermore, pelvic magnetic resonance imaging revealed a cystic lesion measuring 5.1 x 4.2 x 4.0 cm at the site of the previous hysterotomy (Figure 2a). Reddish-brown pus was aspirated transvaginally (Figure 2b). These findings were consistent with an infected uterine diverticulum. The patient was administered intravenous ceftriaxone and metronidazole. Because the patient wanted a second child, a transvaginal uterine diverticulectomy was performed (Figure 2c-f). Postoperatively, her abdominal pain resolved completely. At the three-year follow-up, she was still pain-free. Informed consent was obtained from the patient for the publication of this report.

Uterine diverticula commonly develop after cesarean sections^{1, 2} and are usually small and asymptomatic. A large infected diverticulum is rare³ and may cause abdominal pain, which was observed in our patient. In such patients, transvaginal uterine diverticulectomy is a feasible treatment option.