ureteritis cystica ( uc ) is usually suspected when defects of filling are seen in the ureter in contrasted images of the urinary tract . although is the condition is usually an incidental finding during the evaluation of the urinary tract , it presents occasionally with acute flank pain . a urinalysis showed a ph of 6 , was positive for haemoglobin and leukocyte esterase ( + + ) . bilateral renal morphology and function were normal including a normal left ureter . in the distal right ureter cytology of the ureteral washings was also negative for malignant cells . to further refine the diagnosis computerized axial tomography ( ct ) and urological magnetic resonance ( mru ) both studies showed that the right ureter was occupied from the crossing of the iliac vessels to the bladder by material with characteristics soft tissue . there was no evidence of retroperitoneal , iliac or inguinal lymphadenopathy , or hepatic lesions ( figs . 2 and 3 ) . in view of these findings a biopsy was negative for cancer . with the presumptive diagnosis of ureteritis cystica , we opted for observation with annual follow - up . the patient remains asymptomatic and free of urinary tract infections , haematuria or renal pain . ureteritis cystica is defined as the cystic transformation of the epithelial nest of brunn , with the appearance of numerous cysts containing clear fluid with sizes between 1 and 10 mm with flattened epithelial walls . it is considered of the result of irritation in nonspecific chronic inflammations.1 other etiological factors that have been postulated include bilharziasis , vitamin a excess and increased immunoglobulin a. none of these factors have been proven to play a specific role.2 ureteritis cystica is an infrequent condition which is predominantly found in adults females,3 but also reported to occur in men and children . although usually unilateral , bilateral cases have been described.4 the location of the cysts is predominantly in the proximal ureter , but they can be found at any level of the urothelium . the lesions are benign with low potential for degeneration , although occasionally it has been associated with bladder carcinoma or renal carcinoma.4 the clinical presentation is variable . ureteritis cystica is usually detected during the evaluation of urinary tract infections ( 82% ) , lithiasis ( 53% ) or haematuria ( 52%).57 the most commonly used imaging techniques are excretory urography and retrograde pyelography . in these imaging studies one can observe numerous defects of filling with well - defined , rounded smooth contours often with a  scalloping appearance.7 in cases where the diagnosis is uncertain , as was the case in our patient , ct scan and mru can be used to better define the nature of the lesions , their extent , the presence of other abnormalities . other lesion that can have a similar appearance include , ( radiolucent stones , clots , veins , air bubbles , tuberculous ureteritis).8 when the imaging studies are not conclusive , ureteroscopy plays a fundamental roll in the ability to directly visualize the cystic formations and to take biopsies in order to realize an anatomo - pathological analysis.7 in fact , many authors consider endoscopic diagnosis as the most appropriate in these cases.6 the treatment consists of eliminating the process which is causing the inflammation ( infection , lithiasis ) , although in those cases in which obstruction other measures may be appropriate . in table 1 imaging studies should be complemented with ureteroscopy and biopsy when indicated when tumour is suspected .
ureteritis cystica is an uncommon cause of acute renal pain . 
 the aetiology remains unclear and the diagnosis may be difficult to establish . 
 we report the case of a 29 year old woman with a history of repeated urinary tract infections presenting with acute renal colic in the absence of lithiasis . 
 we review the diagnostic tools available to make the diagnosis and the recent pertinent literature .