Case Presentation: A 23-year-old woman presented with left lower abdominal pain with mildly elevated creatinine that was identified on routine blood draw at her urology appointment. She had no urinary symptoms; UA and pregnancy test were negative. CT abdomen showed hydronephrosis in the left kidney as well as bilateral ureteral thickening. One month prior, she had a right ureter stent placed after she presented with acute kidney injury, and CT abdomen at that time showed evidence of right hydronephrosis and bilateral proximal ureteral thickening. Biopsies of ureter specimens showed normal urothelium with signs of chronic inflammation. Further workup was negative including chest x-ray, complement activity, and other autoimmune markers. During the second admission, a stent was placed in the left ureter and repeat biopsies of both the right and left ureters showed same findings of benign epithelial growth and chronic inflammation. Per operative report, the region of the ureter thickening had the gross appearance of ureteritis cystica (UC). However, upon further questioning the patient had a history of only one urinary tract infection, no kidney stones, and no other concerning history for this presentation. Patient was discharged home symptom free and will follow up with urology.

Discussion: UC is a rare, benign condition of the ureters that can be a challenge to diagnose. It has classically been documented in older female patients with a history of recurrent urinary tract infections or kidney stones. Most of the literature points toward unilateral ureter involvement, with rare cases of bilateral findings. Pathological features of UC include areas of glandular metaplasia secondary to chronic urothelial inflammation. Proliferation of epithelial bodies into the underlying mucosa leads to the formation of small cysts called von Brunn nests. In most patients UC is incidentally discovered during urinary tract imaging for other reasons (hematuria, infection and calculi). The most common radiological appearance of UC is numerous small, relatively uniform filling defects involving the ureters and less commonly the renal pelvis. Various therapies have been reported in the literature, including ureteral dilation or mechanical disruption of cysts, ureteral catheterization, silver nitrate instillation and long-term antibiotic therapy. However, more recently a conservative approach was recommended in the absence of infection or obstruction.

Conclusions: This case may demonstrate an idiopathic origin of ureteritis cystica, although the bilateral and diffuse involvement, lack of previous urological history, and patient age are unusual and may warrant further workup towards other diagnoses. The etiology of ureteritis cystica is poorly understood and further investigations should aim to describe typical presentation, diagnosis, and management guidelines for this process.