A 43-year-old female patient was admitted due to acute urinary retention, indwelling urinary catheter, and intermittent bilateral lumbar and lower abdominal pain which began one day prior. Six days prior to admission, she experienced macroscopic hematuria but did not exhibit any symptoms of accompanying pain, incontinence, lumbago, fever, nausea or vomiting. One day prior, she had experienced dysuria and sought emergency care at another hospital. Urinary catheterisation was performed at the emergency ward, and a renal ultrasound revealed an echogenic mass measuring 6.5 cm × 3.0 cm adjacent to the catheter, thought to be a blood clot. The patient was transferred to our institution.The patient did not exhibit chills, fever or nausea, though she reported that menstruation had commenced the day before, and also that she had a laparascopic myomectomy for uterine fibroids performed over five months ago. Physical examination revealed that vital signs