A 15-year-old girl presented with severe pain upon terminal micturition, a pain that persisted for approximately 2 hours. When pain occurred, she was unable to move. The pain had been present for more than 1 month. She was treated with multiple antimicrobials, but no improvement was observed. Although urinalysis revealed a high white blood cell count, urine culture, cytology, polymerase chain reaction for tuberculosis, and adenovirus infection were all negative. The blood interferon-gamma assay for tuberculosis infection was also negative. She underwent cystoscopy, hydro-distention, and bladder biopsy under general anesthesia. Cystoscopy demonstrated severe erosion throughout the trigone (Fig. 1). Post-distension capillary hemorrhage was observed in only a small part of the posterior wall. Her bladder capacity was 700 mL at 80 cm H2O. Electric fulguration was performed for the trigonal ulcer. Severe inflammation with granulation and lymphocyte infiltration were found on histological assessment of the bladder biopsy from the trigone (Fig. 2). Postoperatively, her symptom improved temporarily, but gradually returned to the preoperative status 1 month later. Although several medications were tried in combination, including suplatast tosilate at 100 mg TID, tranexamic acid at 250 mg TID, potassium citrate/sodium citrate hydrate at 1 g TID, and loxoprofen sodium hydrate at 60 mg TID, her symptoms did not improve. Two months after the first operation, she underwent the second surgery. The trigonal ulcer had recurred and electric fulguration was performed again. The symptom was relieved temporarily, similar to that after the first surgery. Weekly bladder injections of 50 mL of 50% dimethyl sulfoxide were continued for 10 weeks. However, her symptoms did not improve and she was unable to attend school. Thus, the third surgery was scheduled 7 months after the second procedure. During the third surgery, complete electric resection was performed for the recurrent trigonal ulcer (Fig. 3). After the third procedure, pain on urination disappeared (Table 1). She has had no pain without medication for 15 months postoperatively.