Calyceal diverticulum of the kidney - diagnostic imaging dilemma in pediatric patients - case report

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.

Calyceal diverticulum of the kidney in pediatric patients - Is it as rare as you might think?

OBJECTIVE

Calyceal diverticulum (CD) is rarely diagnosed in children. It mimics other cystic lesions of the kidney and may be very difficult to identify. Displaying the communication of these fluid-filled cavities with the collecting system of the kidney via imaging methods is the key diagnostic method. The purpose of this study is to determine the presence of calyceal diverticulum in pediatric patients followed up due to simple renal cyst and/or parapelvic cyst.

MATERIAL, AND METHOD

Patients who were newly diagnosed or being followed up with the ultrasonographic diagnosis of simple cyst(s) or parapelvic cyst(s) in the Department of Pediatric Nephrology of Izmir University of Health Sciences Tepecik Training and Research Hospital between December 2015 and July 2018 were included in the study. Age, gender, admission symptoms, recurrent urinary tract infections, stone disease, trauma history, accompanying urinary system and systemic anomalies, localization, and size of the cyst(s) at admission and during follow-up, treatment type and developing complications were noted. Contrast MR urography was applied to all patients.

RESULTS

A total of 43 patients [mean age:132 ± 54.9 (12-228) months] including 25 girls were enrolled in the study. The mean follow-up period was 36. 74 ± 19 (1-90) months. The cysts were located mostly in the right kidney and also in the upper pole of the kidney. The mean cyst size was 20.4 ± 11 (8-58) mm at admission, and comparably 20.3 ± 8.6 (10-45) mm at the end of the follow-up. In contrast MR urography, a total of 16 cases were observed at first glance to be associated with pelvicalyceal system. However, in the postcontrast images taken at the 5th minute it was determined that 9 of them were compatible with calyceal diverticulum.

CONCLUSION

Although it is thought that well-circumscribed solitary renal fluid collections may be thought to be a simple renal cyst at first glance, the differential diagnosis of calyceal diverticulum (CD) should be absolutely kept in mind. Contrast studies and late-phase postcontrast images are needed for the diagnosis of CD. Although the standard management of CDs in children is conservative, surgical intervention may be rarely required.

Differentiation of simple renal parenchymal cyst and calyceal diverticulum

BACKGROUND

Calyceal diverticulum is the cystic eventration of the upper urinary tract within the renal parenchyma, which gives the first impression of a simple renal cyst and therefore can easily be misdiagnosed. We conducted a study to assess the role of static-fluid magnetic resonance (MR) urography in the differentiation of renal parenchymal cysts and calyceal diverticulum in comparison with focused renal ultrasonography (US).

METHODS

Focused renal US, static-fluid, and excretory MR urography studies of 45 children who were admitted to our pediatric nephrology department with a diagnosis of renal cyst were reviewed retrospectively. Excretory MR urography was accepted as gold standard for the diagnosis of calyceal diverticulum. Sensitivity and specificity of focused renal US and static fluid MR urography in the diagnosis of renal calyceal diverticulum were assessed. Interobserver agreement between three radiologists in the diagnosis of calyceal diverticulum on MRI was also evaluated.

RESULTS

The study included 29 patients (13 boys and 16 girls) aged between 6-18 years (mean 11.5 ± 4.1). Five calyceal diverticula and 24 solitary renal parenchymal cysts were diagnosed. The sensitivity and the specificity of focused renal US were 40% and 100% in the diagnosis of calyceal diverticulum. The sensitivity and the specificity of static-fluid MR urography were 100% and 91.6%, respectively. The degree of interobserver agreement was excellent for the diagnosis of diverticulum for static-fluid MR urography (κ = 0.86, 95% CI: 0.71-1.00).

CONCLUSIONS

Static-fluid MR urography can be successfully used in children for the differentiation of renal parenchymal cyst and calyceal diverticulum due to its high sensitivity and specificity, without exposing children to ionizing radiation or intravenous contrast agents.

Challenges in the diagnosis of calyceal diverticulum: A report of two cases and review of the literature

BACKGROUND

Calyceal diverticula outpouchings that occur rarely in the upper collecting system of the kidney and is often difficult to detect. In this study, we present two cases of calyceal diverticula and discuss their clinical characteristics and radiologic features.

PATIENTS AND METHODS

In the presented two cases, we applied several imaging examinations, including delayed intravenous pyelography, retrograde pyelography and axial computerized tomographic (CT) scanning of the kidneys with and without contrast. Serum creatinine levels in fluid withdrawn from the diverticula were found to be significantly higher than the simultaneous serum creatinine levels. Intravenous injection of methylene blue through a ureteral catheter was also aided in the diagnosis. Calyceal diverticulum neck dilatation was performed through a percutaneous nephroscope.ResultsThe two cases were diagnosed preoperatively and the operation was successful performed. The nephrostomy tube was removed seven days after surgery without complications. CT scans of the kidney after six months showed that the size of the calyceal diverticulum of two patients were considerably smaller than pre-surgery. There were no reports of pain in the lumbar region or other discomfort.

COMMENTS

Diagnosis of calyceal diverticulum mainly depend on a variety of imaging examinations, including the delayed intravenous pyelography, retrograde pyelography, and kidney CT plain scan plus enhanced scan. If the patient cannot be diagnosed by above methods, cyst fluid can be aspirated percutaneously to measure the preoperative creatinine level. If it is significantly higher than the serum creatinine level, the cyst fluid is considered urine, which can assist in the diagnosis of calyceal diverticulum. A ureteral catheter should also be inserted before operation namely, intravenous injection of methylene blue through a ureteral catheter is helpful for diagnosis. The choice of surgical treatment is based on the size and location of calyceal diverticulum and clinical manifestations.