Multiple Metachronous Fibroepithelial Polyps in Children Yoshiyuki Kojima, Sarah M. Lambert, Brian L. Steixner, Nicholas Laryngakis and Pasquale Casale* From the Division of Urology, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, and Department of Nephro-Urology, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan (YK)
Purpose: We present our experience with a new phenotype of fibroepithelial polyps recurring in the urinary tract in children after robotic or laparoscopic pyeloplasty, and discuss the most appropriate treatment for these multiple metachronous neoplasms. Materials and Methods: At our institution 14 children had fibroepithelial polyps as the cause of ureteropelvic junction obstruction at pyeloplasty. Of the patients 12 had at least 1 additional polyp in the ureter, necessitating concomitant ureteroscopy at either robotic or laparoscopic pyeloplasty. Of these 12 patients 9 had followup of at least 1 year. Results: In 6 patients with at least 1 year of followup neoplasms were seen on retrograde pyelography and ureteroscopy that were not present on ureteroscopy at pyeloplasty. At 6 months after stent removal following the first recurrence 2 patients (33%) showed a second recurrence on imaging at a different location in the upper tract requiring laser ablation. One of these patients had a third recurrence that required further intervention before all were disease-free. No major intraoperative or preoperative complications developed. Conclusions: We should always consider the possibility of recurrent fibroepithelial polyps in children with ureteropelvic junction obstruction, and recommend routine retrograde pyelography and ureteroscopy at stent removal after laparoscopic or robotic pyeloplasty. Although ureteroscopic management seems to be the most appropriate modality in children with multiple metachronous fibroepithelial polyps, larger studies are needed.
Abbreviations and Acronyms FEP ⫽ fibroepithelial polyp MRU ⫽ magnetic resonance urethrography RGP ⫽ retrograde pyelography UPJ ⫽ ureteropelvic junction UPJO ⫽ ureteropelvic junction obstruction US ⫽ ultrasound Submitted for publication April 26, 2010. * Correspondence: Division of Urology, Children’s Hospital of Philadelphia, 34th St. and Civic Center Blvd., Wood Building, 3rd floor, Philadelphia, Pennsylvania 19104 (telephone: 215-590-2754; FAX: 215-590-3985; e-mail: [email protected]
Key Words: child; endoscopy; neoplasm recurrence, local; neoplasms, fibroepithelial; ureteral obstruction FIBROEPITHELIAL polyps of the urinary tract are benign mucosal projections that rarely present as ureteropelvic junction obstruction in children. These polyps are generally diagnosed at pyeloplasty, and they are identified in 0.5% of all children undergoing pyeloplasty.1 The etiology of fibroepithelial polyps is unclear but the need for conservative surgery should be emphasized. FEPs typically recur at the site of previous resection, with the belief
being that the primary tumor was not completely ablated. There are few reports on recurrent FEPs in children.2 We present our experience with a new phenotype of FEP in a group of children with new occurrence in the urinary tract after laparoscopic or robotic pyeloplasty, and discuss the most appropriate management of multiple metachronous FEPs. To our knowledge this is the first reported series of multiple metachronous FEPs in children.
0022-5347/11/1853-1053/0 THE JOURNAL OF UROLOGY® © 2011 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
Vol. 185, 1053-1057, March 2011 Printed in U.S.A. DOI:10.1016/j.juro.2010.10.046
MULTIPLE METACHRONOUS FIBROEPITHELIAL POLYPS
MATERIALS AND METHODS Of the first 200 minimally invasive pyeloplasties performed at our institution 14 cases were observed operatively to have FEPs as the cause of UPJ obstruction. Of the 14 patients 12 had at least 1 additional polyp in the ureter necessitating concomitant ureteroscopy at laparoscopic or robotic pyeloplasty. Of these 12 patients 9 had recurrent pain during followup of at least 1 year. These patients comprised the group of interest and included 7 boys and 2 girls 5 to 14 years old (mean 12). Mean followup was 21 months (range 12 to 39).
RESULTS Before pyeloplasty all patients underwent MRU to delineate obstructive patterns. All patients had delayed cortical transit time and delay in visualization of the ureter, with corresponding Patlak values corrected for volume indicating obstruction before pyeloplasty. Of patients with at least 1 year of followup the initial imaging modality was US in 8 and excretory urography in 1. Further imaging included MRU in 7 patients and computerized tomography in 2. None of the FEPs was seen on preoperative imaging. All patients had 1 FEP at the UPJ with at least 1 additional ureteral polyp at initial intervention, and a stent was left in place for 6 weeks. Ureteroscopic intervention with biopsy followed by laser ablation was performed via trocar when more than 1 polyp was identified at initial pyeloplasty. All patients subsequently underwent RGP at stent removal. The clinical course of the patients with multiple polyps is outlined in figure 1. All 9 patients presented with pain 2 months after stent removal. Six patients had evidence of neoplasms on RGP and ureteroscopy that were not present on ureteroscopy at pyeloplasty (fig. 2). In these 6 patients laser ablation was performed with stent placement and followup RGP 6 to 8 weeks later. Our ureteroscopic technique includes cannulation of the ureteral orifice with a 4Fr or 5Fr ureteral
catheter to perform RGP at the beginning of the procedure, placement of a working guidewire in the renal pelvis to maintain access and placement of a safety wire for ureteroscopy. No active dilation of ureteral orifices was performed. Ureteroscopy was then done in combination with holmium:YAG laser resection of the polyp using an AUR™ 7 or Flex-X/ X2™ flexible ureteroscope. No rigid ureteroscopy was performed. Continuous irrigation and intermittent manual pumping of an irrigant were done to obtain a clear ureteroscopic view. Each resected FEP was removed with grasping or basket forceps. All polyps were pedunculated in nature. A 4.7Fr double pigtail ureteral stent was placed at the end of the procedure and removed at 6 to 8 weeks of followup. At 6 months after stent removal following the first recurrence 2 patients (33%) demonstrated a second recurrence on imaging at a different location in the upper tract requiring laser ablation. Of these patients 1 had a third recurrence that required further intervention before all were disease-free. No major intraoperative or preoperative complications developed. All patients had pathologically proved FEP in all occurrences, with no evidence of malignancy (fig. 3). Of patients who had undergone MRU retrospective review revealed FEP in 2 before pyeloplasty, which correlated to intraoperative findings (fig. 4). All patients are currently being followed with annual MRU for any recurrence of symptoms. In retrospect, FEP could only be identified in 3 patients (by US in 1 and MRU in 2).
DISCUSSION We present our experience with multiple metachronous FEPs in the urinary tract after robotic or laparoscopic pyeloplasty in children. FEPs of the upper urinary tract are uncommon in children, with only about 40 reported cases involving UPJO. Adey et al
Figure 1. Clinical course of 9 patients with multiple metachronous FEPs
MULTIPLE METACHRONOUS FIBROEPITHELIAL POLYPS
Figure 2. A, retrograde pyelogram demonstrates filling defect (arrows) in UPJ and ureter corresponding to FEPs. B, ureteroscopic view of UPJ reveals FEP.
reported on 9 patients with UPJO secondary to FEPs in a retrospective review from 1967 to 2002.1 Niu et al also reported 8 cases of FEP of the UPJ with hydronephrosis.3 At our institution we prefer conventional or robot assisted laparoscopic pyeloplasty for children with
UPJO. During a period of 4 years 14 patients were observed at pyeloplasty to have FEPs as the cause of UPJO. Despite advances in urological imaging, differentiating FEPs from more common causes of UPJO remains difficult. UPJO caused by FEPs presents similarly to other types of UPJO. In the series
Figure 3. Pathological findings show FEPs composed of loose fibrovascular connective tissue covered with layer of normal urothelium seen under low and high power view. A, H&E, reduced from ⫻4. B and C, H&E, reduced from ⫻2.
MULTIPLE METACHRONOUS FIBROEPITHELIAL POLYPS
Figure 4. FEPs (arrows) in 2 patients before pyeloplasty correlated to intraoperative findings. A, US. B, MRU.
of Adey et al only 22% of cases had a diagnosis of FEP suggested preoperatively.1 In our study no FEPs were noted on preoperative imaging. Of 7 patients with available MRU and ultrasound retrospective review of the preoperative images showed FEP in 3 before pyeloplasty correlating to intraoperative findings (2 on MRU and 1 on US). As a result, these cases are usually diagnosed during pyeloplasty. MRU was performed in followup to rule out recurrence of obstruction as well as hopefully display any filling defects that might become apparent on 3-dimensional reconstruction. The etiology of FEP remains unknown. Although various theories have been proposed, including chronic irritation, chronic infection, developmental factors, allergic factors, obstruction, trauma and hormonal disturbance, developmental defects are the most frequently suspected cause.4 There are several reports on multiple or bilateral FEPs in the upper urinary tract in children.5– 8 However, only Ruiz-Lopez et al have reported recurrent FEP in a 7-year-old boy.2 Of our 14 cases of FEPs causing UPJO 12 involved at least 1 additional polyp in the ureter necessitating concomitant ureteroscopy at robotic or laparoscopic pyeloplasty. Of the 9 cases with followup of at least 1 year 6 had evidence of neoplasms. Our experience with this type of entity is new. We are unsure why these FEPs are occurring, although inflammation after pyeloplasty and allergic response to ureteral stent may be possible causes of multiple metachronous FEPs. Therefore, continued surveillance for recurrence is paramount. Open surgery has traditionally been performed for patients with ureteral FEPs. However, more recent reports have described the use of ureteroscopy with a holmium laser. There are several studies of endoscopic management in adults. Lam et al reported their experience with percutaneous and ureteroscopic treatment of FEPs of the renal pelvis and ureter via electroresection or holmium laser resection.9 Carey and Bird reported endoscopic manage-
ment in a man with 10 separate FEPs arising in a single ureter.10 Finally, Sun et al reported their experience with endoscopic management in 5 adults with FEPs.11 In these studies no recurrence was seen during followup. Recently Childs et al reported endoscopic treatment in 12 patients, with FEP recurring 26 months after primary ureteroscopy in a single patient.12 Secondary endoscopic treatment was successful in managing this recurrence. Reports of endoscopic management in children with FEPs are limited. Bhalla et al reported the first documented instance of a child treated with ureteroscopic fulguration of the base of bilateral FEPs using a holmium laser.5 Romesburg et al subsequently reported an instance of bilateral UPJO secondary to FEPs in a child, also treated with endoscopy and holmium laser ablation.6 There is no general consensus regarding treatment of recurrent FEPs. Available options for management may be endoscopic or open, conventional laparoscopic or robotic surgery. Ruiz-Lopez et al reported their experience with secondary open surgery (resection of ureteral segment with 2 recurrent FEPs and ureteral anastomosis) for a child with recurrent ureteral FEPs after primary open surgery.2 Generally redo open, laparoscopic and robotic surgery is technically more challenging than primary surgery because of extensive scarring, fibrosis and adhesions from the prior procedure. In addition, redo laparoscopic or robotic pyeloplasty does not seem to be appropriate for multiple recurrent FEPs. The advantages of endoscopy are the ability to start treatment as soon as a diagnosis is made and to permit minimally invasive surgery. Therefore, we performed endoscopic laser ablation for recurrent FEPs. In our series endoscopic laser ablation was successful in 4 of the 6 patients (67%) with recurrent FEPs, although 2 (33%) had new FEPs at a different location in the upper tract requiring additional laser ablation before all were disease-free.
MULTIPLE METACHRONOUS FIBROEPITHELIAL POLYPS
In terms of overall safety pediatric ureteroscopy has been validated as a safe modality in several contemporary series, although ureteral wall injury and ureteral stricture are possible complications.6,12–16 Ureteroscopic management seems to be the most appropriate modality in treating multiple metachronous FEPs after pyeloplasty in children. However, since there is a possibility of recurrence at a different location of the ureter irrespective of treatment, careful followup is recommended.
CONCLUSIONS We present our experience with multiple metachronous FEPs after laparoscopic or robotic pyeloplasty. Urologists should always consider the possibility of recurrence in children with FEPs causing UPJO. We recommend routine RGP and ureteroscopy at stent removal after pyeloplasty. Although ureteroscopic management seems to be the most appropriate modality for children with recurrent FEPs, larger studies are needed.
REFERENCES 1. Adey GS, Vargas SO, Retik AB et al: Fibroepithelial polyps causing ureteropelvic junction obstruction in children. J Urol 2003; 169: 1834.
obstruction due to fibroepithelial polyps and review of the literature. Urology 2009; 73: 929.e9.
12. Childs MA, Umbreit EC, Krambeck AE et al: Fibroepithelial polyps of the ureter: a single-institutional experience. J Endourol 2009; 23: 1415.
2. Ruiz-Lopez MJ, Ramirez-Garrido F, NoguerasOcana M et al: Recurrent ureteric fibroepithelial polyp in a child. Eur J Pediatr 2004; 163: 124.
7. Bartone FF, Johansson SL, Markin RJ et al: Bilateral fibroepithelial polyps of ureter in a child. Urology 1990; 35: 519.
13. Minevich E, Defoor W, Reddy P et al: Ureteroscopy is safe and effective in prepubertal children. J Urol 2005; 174: 276.
3. Niu ZB, Yang Y, Hou Y et al: Ureteral polyps: an etiological factor of hydronephrosis in children that should not be ignored. Pediatr Surg Int 2007; 23: 323.
8. Lavelle JP, Knisely AS and Bellinger MF: Benign fibroepithelial polyps causing symptomatic bilateral intermittent hydroureteronephrosis. J Urol 1997; 158: 569.
14. Smaldone MC, Cannon GM Jr, Wu HY et al: Is ureteroscopy first line treatment for pediatric stone disease? J Urol 2007; 178: 2128.
4. Cassar Delia E, Joseph VT and Sherwood W: Fibroepithelial polyps causing ureteropelvic junction obstruction in children—a case report and review article. Eur J Pediatr Surg 2007; 17: 142.
9. Lam JS, Bingham JB and Gupta M: Endoscopic treatment of fibroepithelial polyps of the renal pelvis and ureter. Urology 2003; 62: 810.
5. Bhalla RS, Schulsinger DA and Wasnick RJ: Treatment of bilateral fibroepithelial polyps in a child. J Endourol 2002; 16: 581. 6. Romesburg JW, Stein RJ, Desai MM et al: Treatment of child with bilateral ureteropelvic junction
10. Carey RI and Bird VG: Endoscopic management of 10 separate fibroepithelial polyps arising in a single ureter. Urology 2006; 67: 413. 11. Sun Y, Xu C, Wen X et al: Is endoscopic management suitable for long ureteral fibroepithelial polyps? J Endourol 2008; 22: 1459.
15. Kim SS, Kolon TF, Canter D et al: Pediatric flexible ureteroscopic lithotripsy: the Children’s Hospital of Philadelphia experience. J Urol 2008; 180: 2616. 16. Romesburg JW, Stein RJ, Desai MM et al: Treatment of child with bilateral ureteropelvic junction obstruction due to fibroepithelial polyps and review of the literature. Urology 2009; 73: 929.e9.