Swathed Ureter, an Enigma in Diagnosis- A Pictorial Essay

Urinary tract Obstruction (UTO) an alarming but common clinical condition affecting more women than men at any age, though common in 20 to 60 years of age having an overall incidence of hydronephrosis in 3.1% of autopsy. Over time, UTO results in irreversible loss of numerous nephrons leading to obstructive nephropathy and end-stage renal failure. If the obstruction of the ureter is partial and brief and if intervention is done at correct time, after relief of obstruction. complete recovery of renal function is possible. One has to be aware that UTO lasting more than 24 hours may cause irreversible loss of renal function. Radiology investigations may show UTO without ureteric dilation and dilation of ureter without UTO creating potential pitfall in radiologic diagnosis of UTO. Most of the UTO due to calculi are readily identifiable whereas many cases of ureteric exterior encasement are frequently missed from early detection even by experienced clinicians and radiologists. Failure in recognition of the encasement of ureters and causes may lead to mistaken diagnosis with resultant inappropriate management [1]. The most common benign cause of encasement of ureters is retroperitoneal fibrosis and the most frequent malignant causes are extension from an adjacent primary tumour such as sarcoma, lymphoma, (E.g.: sarcomas and lymphomas of uterus, ovaries, urinary bladder and prostate). Among benign conditions of swathed ureters, Extrinsic benign tumours, Retroperitoneal lymphadenopathy, Retroperitoneal abscess, Retroperitoneal fibrosis, Inflammatory abdominal aortic aneurysm or iliac artery aneurysm, and Endometriosis are significant. Chronic fibrosing conditions of the abdomen may involve multiple systems by their proliferative deep fibromatoses which form pseudotumor which cannot be differentiated from neoplastic conditions at imaging. Peri-ureteral inflammation (E.g.: peritonitis, salpingitis, and diverticulitis), multifocal idiopathic fibrosclerosis and schistosomiasis are some other known causes. Encasement may also be associated with blocked ureter [2-4]. Besides the inherent features of the disease causing the encasement of the ureters, in general, clinical features include recurrent fever, pain abdomen, oliguria, frequency, dysuria, haematuria nocturia, and hypertension. Patients may also present with fatigue, anorexia, weight loss, fever, hydroceles, scrotal pain, lower extremity oedema, and pulmonary embolism. Since ureters may be affected, various degrees of ureteral obstruction, hydronephrosis, and renal failure are also considered early and common clinical manifestations. In this article, we will review the four important diseases that cause ureteric encasement with some key imaging features for the diagnosis [5,6].