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Symptomatic Parapelvic Cysts in Children: Anatomical and Histological Features, Diagnostic Pitfalls and Urological
Jean-Baptiste Marret1, Thomas Blanc1,2, Andre Balaton3
1Department of Paediatric Surgery and Urology, Hôpital Necker Enfants Malades, APHP, Université de Paris, 149 Rue de Sèvres, 75015 Paris, France.
Insights
Symptomatic parapelvic cysts (PPC) can mimic ureteropelvic junction (UPJ) obstruction. Differentiating these conditions with imaging is crucial for appropriate treatment and avoiding misdiagnosis in children.
Area of Science:
- Pediatric Urology
- Diagnostic Imaging
- Renal Pathology
Background:
- Symptomatic parapelvic cysts (PPC) are rare and can be misdiagnosed as ureteropelvic junction (UPJ) obstruction.
- This study aimed to identify key features of PPC to prevent misdiagnosis.
Observation:
- Four pediatric patients (18 months-8 years) presented with acute renal colic and large intra-sinusal cystic masses on ultrasound, suggestive of UPJ obstruction.
- Renal scintigraphy showed no renal pelvis dilation, with impaired function in two patients. Advanced imaging (CT/MRI) aided diagnosis.
Findings:
- Preoperative and intraoperative pyelography failed to demonstrate communication with the cyst, and the renal pelvis was not visualized in two cases.
- Cyst de-roofing was curative in all patients, with a mean 5-year follow-up showing no recurrence or loss of function.
- Histology confirmed a single flat epithelial cell layer, characteristic of parapelvic cysts.
Implications:
- Parapelvic cysts should be considered in pediatric UPJ obstruction evaluations, especially when ultrasound reveals a medial renal mass without renal pelvis dilation on scintigraphy.
- Complementary imaging work-up is essential for accurate diagnosis and surgical planning.
- Prompt diagnosis and treatment of PPC can lead to asymptomatic recovery and preserved renal function.
Background:
Symptomatic parapelvic cysts (PPC) are rare entities. Our objective is to highlight specific features of PPC to avoid a misdiagnosis of UPJ obstruction.
Methods:
We retrospectively reviewed the records of children managed between 2012-2017.
Results:
All four patients (18 months-8 years) presented with acute renal colic with a large intra-sinusal liquid mass (42-85 mm) on ultrasound, evoking a diagnosis of UPJ obstruction. On preoperative renal scintigraphy (n = 3) there was no dilatation of the renal pelvis and ipsilateral differential function was impaired in 2. Diagnosis of PPC was suspected preoperatively in three children (CT scan (n = 1); MRI (n = 2)) and made peri-operatively (n = 1). Preoperative retrograde pyelography (n = 3) and a further intraoperative retrograde pyelography with methylene blue (n = 1) did not identify communication with the cyst. No renal pelvis was identified in two patients. De-roofing of the cyst was curative in all cases at 5 years mean follow-up (no leakage, cyst recurrence or loss of function) and all 4 patients became asymptomatic after surgery. Histology demonstrated a single flat epithelial cell layer. Renal function normalized in one patient but remained impaired in the other.
Conclusion:
In case of symptoms of UPJ obstruction with a medial renal liquid mass on ultrasound, PPC should be considered when no dilatated pelvis on renal scan is identified. In such cases, a complementary imaging work-up is mandatory prior to surgery.
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