Ureteritis Cystica Presenting as a Single Polypoid Mass

A 40-year-old woman complained of a 6-month history of left flank pain. No hematuria or previous diagnosis of urolithiasis was reported. Computed tomography scan revealed a left-sided hydronephrosis with atrophic kidney and a solid mass within the dilated portion of the left ureter. Renal scintigraphy displayed decreased clearance in the left kidney and diuretic renal scan proved obstructive uropathy. On the basis of radiological findings, left nephroureterectomy was advised due to the high likelihood of malignancy. Gross examination showed marked hydronephrosis and a 5 × 3.2 cm polypoid, multicystic, mass localized in the left mid ureter. Histologically, the lesion consisted of cystic structures lined with benign-appearing urothelium with intact umbrella cells. Necrosis and significant mitotic activity were absent. Immunohistochemistry demonstrated positivity for CK7 and CK20, whereas Ki-67 labelled less than 2% of nuclei within the epithelial nests. These findings were consistent with ureteritis cystica. Ureteritis cystica seems to be related to urothelial chronic inflammation, with stones and infections claimed as potential causative factors. Ureteritis cystica seldom gives rise to grossly visible, nonobstructive cysts or pedunculated polyps. Treatment consists of eliminating the inflammatory noxae, although in cases where ureteritis cystica causes obstruction, other measures may be appropriate.