Ureteropelvic junction obstruction - mimicking an "elephant head" on magnetic resonance imaging.

Ureteropelvic junction obstruction (UPJO) with giant hydronephrosis is relatively rare in adults as compared to children. Most of the UPJO reported or seen in daily practice have a distinct hydronephrosis with a narrow ureteropelvic junction and a collapsed ureter distally. We present images a case of an adult female with Left UPJO, which on MRI mimicked an 'elephant head'.

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) is diagnosed by various modalities ranging from ultrasound of abdomen to diethylenetriaminepentaacetic acid (DTPA) scan. However, some cases might present with a distinct image on a radiological investigation and may pose a diagnostic dilemma. We report such a case with an aim to present a varied magnetic resonance imaging (MRI) presentation of UPJO.

CASE REPORT

A 19-year-old female presented with dull aching left flank pain for the past 6 months. The ultrasonography of abdomen suggested of left gross hydroureteronephrosis. MRI showed a grossly dilated left renal pelvis and a dilated tortuous ureter, suggestive of the primary obstructive megaureter, mimicking an “elephant head” appearance [Figure 1]. The DTPA scan confirmed poorly functioning left kidney (split function 9%), and the patient underwent left simple nephrectomy. Intraoperatively, however, there was a grossly dilated and tortuous left renal pelvis extending all the way up to the bladder with a collapsed short segment of ureter connecting the left renal pelvis to the bladder. Histopathology report was suggestive of Chronic pyelonephritis in a grossly hydronephrotic kidney with UPJO. The patient recovered uneventfully.

Figure 1

Coronal reconstruction of magnetic resonance image and its analogy to an “elephant head”

DISCUSSION

Giant hydronephrosis due to UPJO in adults, though rare, have been often reported.[12] Almost all of them have grossly dilated pelvis with an obvious distinct ureteropelvic junction with a distal collapsed ureter. With the experience of this case, it can be learnt that a dilated renal pelvis may also undergo tortuous dilatation changes mimicking primary obstructive megaureter. However, whether this UPJO had its origin in lower abdomen before ascent of the kidney or a dilated renal pelvis has pushed the ureteropelvic junction all the way down to the bladder, remains a matter of further research.

CONCLUSION

Even in today's advanced urological practice with an investigation as advanced as an MRI, intraoperative findings might show up an entirely different picture from the preoperative imaging and may considerably influence the management.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.