# A case report of renal cyst communication regression secondary to hydroureteronephrosis decompression

## TL;DR

A 79-year-old cancer patient's kidney cyst communication disappeared after decompression, possibly due to pressure changes.

## Contribution

This case report highlights a rare regression of renal cyst communication following decompression.

## Key findings

- Contrast within the renal cyst disappeared after nephrostomy tube decompression.
- The communication was not re-established, unlike typical renal cyst communications.
- Pressure-related mechanisms may explain the regression observed.

## Abstract

Renal cysts, which are commonly detected incidentally on imaging, often remain asymptomatic. A small percentage may lead to complications such as hemorrhage, infection, or mass effect. This can cause elevated intrapelvic pressure and possible spontaneous rupture, which can establish a communication with the calyceal system. This report presents the case of a 79-year-old male with urothelial carcinoma who developed right-sided hydronephrosis secondary to obstructive malignancy. CT and fluoroscopic imaging revealed a large urinoma with a communication between the collecting system and adjacent renal cyst. Following nephrostomy tube decompression, the presence of contrast within the renal cyst that helped establish the initial communication disappeared and was unable to be re-established. This disappearance contrasts the continued communication seen with typical renal cyst communications and may have occurred due to possible pressure related mechanisms.