A Rare Vascular Anomaly Causing Left Hydroureteronephrosis

In children, hydroureteronephrosis due to ureterovesical stenosis may develop from reflux or obstruction. In diagnostic cystoscopy, not only the findings of the ureteral orifice and ureteral tracing but also the findings of accompanying intra- and extravesical pathologies should not be overlooked. A five-year-old male patient had increased left hydroureteronephrosis on ultrasound follow-up and Mag-3 scintigraphy showed partial obstruction. Retrograde pyelography (RPG) was planned for diagnostic purposes. Cystoscopy showed pulsation in the subureteric area of the left ureteral orifice. RPG was performed. Distal passage problems and proximal hydroureteronephrosis were found on the left side. Postoperative abdominal computed tomography (CT) angiography was performed to investigate the cause of arterial pulsation. It was observed that the left iliac artery did not bifurcate at the normal level and was aberrant in the pelvis as an external iliac artery, single arterial structure that was tortuous and slightly wide. At this level, it extended into the posterior neighborhood of the bladder. This anatomical variation and the suburethral neighborhood of the artery caused marked intravesical arterial pulsation. No intervention was performed, and it was noted that if surgical intervention was necessary according to the follow-up, it should be performed in absolute extravesical exploration, considering the existing pathology. Pulsatile mass detected during cystoscopy for intravesical evaluation may be associated with rare extravesical vascular malformations. Following CT angiography, invasive interventions should be carefully planned if necessary. Expansion of invasive procedures without a thorough understanding of extravesical anatomy may lead to serious complications.