Differentiation of simple renal parenchymal cyst and calyceal diverticulum

Cystic kidney diseases in children

Cystic kidney disease comprises a broad group of heterogeneous diseases, which differ greatly in age at onset, disease manifestation, systemic involvement, disease progression, and long-term prognosis. As our understanding of these diseases continues to evolve and new treatment strategies continue to emerge, correctly differentiating and diagnosing these diseases becomes increasingly important. In this review, we aim to highlight the key features of the most relevant cystic kidney diseases, underscore important diagnostic characteristics of each disease, and present specific management options if applicable.

A case report of renal calyceal diverticulum with hypertension in children and review of literature

Background

Renal calyx diverticulum refers to a cystic lesion covered with the transitional epithelium in the renal parenchyma. Although there is no clear evidence that calyx diverticulum can cause hypertension, there exists a close association between the two, and there are few related reports. Herein, we reported the case of a child with renal calyx diverticulum complicated with hypertension and summarized the diagnosis and treatment.

Case presentation

Physical examination of the patient, an 11-year-old child, revealed a left renal cyst with hypertension (155/116 mmHg). There were no related symptoms. Routine urine and blood biochemical examinations showed no abnormalities. Imaging revealed left renal cyst compression causing the hypertension. She underwent renal cyst fluid aspiration and injection of a sclerosing agent into the capsule, but her blood pressure increased again 3 days postoperatively. Color Doppler ultrasonography showed that the size of the left renal cyst was the same as that preoperatively. To further confirm the diagnosis, cystoscopic retrograde ureteropyelography was performed to confirm the diagnosis of renal calyx diverticulum. Subsequently, renal calyceal diverticulum resection and calyx neck enlargement were performed. The operation went smoothly and the blood pressure returned to normal postoperatively. No abnormalities were noted at the 7-month postoperative follow-up.

Conclusion

There exists an association between renal calyx diverticulum and hypertension. Therefore, hypertension can be considered a surgical indication for renal calyx diverticulum. Moreover, renal calyceal diverticulum in children can be easily misdiagnosed as a renal cyst. Therefore, it is important to be vigilant to prevent a series of complications, such as postoperative urine leakage, in such cases.

Identification and characterization of calyceal diverticula with MR urography (MRU) in children

PURPOSE

To determine the MRU imaging findings of calyceal diverticula in a large cohort of children and to compare the frequency of calyceal diverticula in our cohort with what has been previously reported.

METHODS

This was a HIPAA-compliant, IRB-approved retrospective study of all patients with suspected CD based on their medical records. All patients in this study underwent MRU at our institution between 2010 and 2017. Two pediatric radiologists reviewed each MRU blinded to clinical information and other urologic imaging regarding the presence, size, location, and morphology of the cyst and presence/absence of contrast within it. The time when contrast first appeared within the cystic mass was recorded, and a χ² test was used to determine significance on differences between the different characteristics of renal cysts and diverticula.

RESULTS

Fifty children (29 girls and 21 boys; median age of 11.5 years, IQR 7-16) with a total of 66 individual cystic masses were included. 21 (21/66, 31.8%) Cystic masses demonstrated contrast filling and were characterized as diverticula, resulting in a frequency of 26.6 cases per 1000 patients (21/787). The remaining 45 cystic masses (45/66, 68.1%) were cysts. The median diameter of CD was 2.5 cm (IQR 1.5-3.7). Contrast was observed within the cystic mass on average at 4.6 min (SD ± 2.4; range 1.5-13 min). The agreement between both radiologists was 91% (k = 0.78). 6 Cysts and 18 CD were confirmed surgically, MRU demonstrated accurate diagnosis in 100% of those cases.

CONCLUSION

Magnetic resonance urography is reliable in differentiating calyceal diverticula from renal cysts. On MRU, all diverticula were identified within 15 min of contrast administration; hence longer delays in imaging are unnecessary.