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Spontaneous combined rupture of a pelvicalyceal cyst into the collector system and retroperitoneal space during the acquisition of computed tomography scan images: a case report
© Marques et al.; licensee BioMed Central Ltd. 2012
Received: 21 June 2012
Accepted: 10 October 2012
Published: 13 November 2012
Pelvicalyceal cysts are common findings in autopsies and can manifest with a variety of patterns. These cystic lesions are usually a benign entity with no clinical significance unless they enlarge enough to cause compression of the adjacent collecting system and consequently obstructive uropathy. Few cases of the spontaneous rupture of pelvicalyceal renal cysts have been published and to the best of our knowledge there is no report of a combined rupture to collector system and retroperitoneal space documented during a multiphase computed tomography.
We report a case of a ‘real-time’ spontaneous rupture of a pelvicalyceal cyst into the collecting system with fistulization into the retroperitoneum.
The patient was a 78-year-old Caucasian man with a previous history of renal stones and a large pelvicalyceal renal cyst who was admitted to our Emergency department with acute right flank pain.
A multiphase computed tomography was performed and the pre-contrast images demonstrated a right pelvicalyceal renal cyst measuring 12.0 × 6.1cm in the lower pole causing moderate dilation of the upper right renal collection system. In addition, a partially obstructive stone on the left distal ureter with mild left hydronephrosis was noted.
The nephrographic phase did not add any new information. The excretory phase (10-minute delay) demonstrated a spontaneous rupture of the cyst into the pelvicalyceal system with posterior fistulization into the retroperitoneal space.
In this case study we present time-related changes of a rare pelvicalyceal cyst complication, which to the best of our knowledge has fortunately not been previously documented. Analysis of the sequential images and comparison with an earlier scan allowed us to better understand the physiopathological process of the rupture, the clinical presentation and to elaborate hypotheses for its etiopathogenesis.
Pelvicalyceal cysts are common findings in autopsy cases and can manifest with a variety of patterns from multiple small cysts to a large solitary lesion[1, 2]. Their etiology is not very well defined but they are believed to be of lymphatic origin and no hereditary pattern has been shown.
On radiologic images the pelvicalyceal cysts appear as rounded or oval lesions with water attenuation replacing the renal sinus fat and can be difficult to differentiate from hydronephrosis on unenhanced computed tomography (CT), magnetic resonance imaging (MRI) or sonography. The use of contrast-enhanced CT or MRI scan or excretory urography enables this differentiation by demonstrating the renal pelvis filled with contrast medium and dislocated or compressed by the water-attenuation cyst which has no communication with the collecting system and therefore is without contrast in its interior. These examinations are also useful to differentiate renal sinus cysts from calyceal diverticulum, because the last has a narrow passage to the collecting system and will also be filled with contrast medium.
These cystic lesions are usually a benign entity with no clinical significance unless they enlarge enough to cause compression of the adjacent collecting system and consequently obstructive uropathy[2, 3]. Spontaneous rupture is a rare event that has been reported in few cases in which there is drainage to the pelvicalyceal system, the perirenal space or the peritoneal cavity[5–8]. When such complication happens it can lead to symptoms such as abdominal pain or hematuria.
These findings demonstrate a spontaneous rupture between the renal cyst and the pelvicalyceal system with, consequently, fistulization into the retroperitoneal space occurring between venous and excretory phases.
To the best of our knowledge, there is no report of the spontaneous rupture of a pelvicalyceal cyst into the collecting system with posterior fistulization into the retroperitoneal space documented during a multiphase CT scan acquisition. The patient in this case also has a contralateral ureteral stone that might contribute to an increase in pressure in the right kidney.
In addition, the comparison with the 4 months older CT documented a slight increase in the size of the cyst, which probably collaborated for the final outcome.
Increase of intrarenal pressure by administration of endovenous contrast. The presence of contrast media particles inside renal tubules, which are not absorbed by renal cells, causes an osmotic effect leading to a marked increase of water and sodium excretion . This induced diuresis will consequently elevate intrapelvic pressure.
Elevation of filtration rate and urine flow by the right kidney to compensate the obstruction of the left collector system caused by the urolithiasis .
The enlargement of the pelvicalyceal cyst may cause progressive compression in the collector system and consequently high pressures.
In this case study we present time-related changes of a rare pelvicalyceal cyst complication, which to the best of our knowledge has fortunately not been previously documented. Analysis of the sequential images and comparison with an earlier scan allowed us to better understand the physiopathological process of the rupture, and to raise three hypotheses for its etiopathogenesis.
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
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