解除腎水腫促成腎結石移位：腎囊腫除頂術的意外治療效益

孫浩議¹、黃建勳^1,2、張彰琦^1,2、邱逸淳²、邱文祥²

¹臺北市立聯合醫院忠孝院區外科部泌尿科

²國立陽明交通大學醫學院

Cost-Effective Stone Management Achieved Through Unexpected Stone Migration After Cyst Unroofing

Hao-Yi Sun ¹, Ken-J Chien-Hsun Huang ^1,2, Chang-Chi Chang ^1,2, Yi-Chun Chiu ², Allen W. Chiu ²

¹ Division of Urology, Department of Surgery, Zhongxiao Branch, Taipei City Hospital

² National Yang Ming Chiao Tung University, School of Medicine, Taipei, Taiwan

Introduction

Large parapelvic renal cysts can lead to obstructive hydronephrosis, causing symptoms such as flank pain and renal colic. Treatment may be needed to relieve the compression and restore normal urine flow. In cases with concurrent renal stones, interventions like cyst unroofing are generally aimed at resolving the cyst-induced hydronephrosis. However, such procedures may lead to the unexpected migration of renal stones into the ureter, which can ultimately simplify stone management. This case presents a surprising and beneficial outcome following renal cyst unroofing.

Case presentation
A 74-year-old male presented with a year-long history of dull right flank pain, which had worsened over recent months, alongside intermittent urination. Imaging showed a large right parapelvic renal cyst (31x27 mm) causing external compression and right-sided obstructive hydronephrosis, resulting in renal colic. Several small right renal stones were also present, though none were located near the ureteropelvic junction (UPJ). To alleviate the cyst-related hydronephrosis, the patient underwent a right retroperitoneoscopic-assisted unroofing of the renal cyst, aimed solely at relieving external compression.

The procedure was successful in resolving the obstructive hydronephrosis, and the patient was discharged in stable condition. Unexpectedly, within three weeks post-surgery, the patient returned with acute colicky pain characteristic of ureteral obstruction. Imaging revealed that the previously non-obstructive renal stones had migrated to the UPJ, causing internal obstructive hydronephrosis due to the stones. This surprising development enabled cost-effective treatment using ureteroscopic lithotripsy (URSL), without requiring more invasive or complex procedures. The stones were successfully removed, a double-J stent was placed, and the patient’s recovery was smooth, allowing for discharge in stable condition.

Conclusion

This case demonstrates an unexpected yet beneficial outcome of renal cyst unroofing, where the relief of hydronephrosis inadvertently facilitated the migration of renal stones to the UPJ. This outcome eliminated the need for more extensive procedures like retrograde intrarenal surgery (RIRS), allowing for a simpler and cost-effective URSL treatment. Such a favorable “side effect” demonstrates that, for patients with both large renal cysts and renal stones, cyst unroofing can serve not only to relieve hydronephrosis but, in certain cases, may also lead to unanticipated stone migration, simplifying further treatment.