Copy Number Variant Analysis and Genome-wide Association Study Identify Loci with Large Effect for Vesicoureteral Reflux.

BACKGROUND: Vesicoureteral reflux (VUR) is a common, familial genitourinary disorder, and a major cause of pediatric urinary tract infection (UTI) and kidney failure. The genetic basis of VUR is not well understood. METHODS: A diagnostic analysis sought rare, pathogenic copy number variant (CNV) disorders among 1737 patients with VUR. A GWAS was performed in 1395 patients and 5366 controls, of European ancestry. RESULTS: Altogether, 3% of VUR patients harbored an undiagnosed rare CNV disorder, such as the 1q21.1, 16p11.2, 22q11.21, and triple X syndromes ((OR, 3.12; 95% CI, 2.10 to 4.54; P=6.35×10-8) The GWAS identified three study-wide significant and five suggestive loci with large effects (ORs, 1.41-6.9), containing canonical developmental genes expressed in the developing urinary tract (WDPCP, OTX1, BMP5, VANGL1, and WNT5A). In particular, 3.3% of VUR patients were homozygous for an intronic variant in WDPCP (rs13013890; OR, 3.65; 95% CI, 2.39 to 5.56; P=1.86×10-9). This locus was associated with multiple genitourinary phenotypes in the UK Biobank and eMERGE studies. Analysis of Wnt5a mutant mice confirmed the role of Wnt5a signaling in bladder and ureteric morphogenesis. CONCLUSIONS: These data demonstrate the genetic heterogeneity of VUR. Altogether, 6% of patients with VUR harbored a rare CNV or a common variant genotype conferring an OR >3. Identification of these genetic risk factors has multiple implications for clinical care and for analysis of outcomes in VUR.

Diagnostic Utility of Exome Sequencing for Kidney Disease.

BACKGROUND: Exome sequencing is emerging as a first-line diagnostic method in some clinical disciplines, but its usefulness has yet to be examined for most constitutional disorders in adults, including chronic kidney disease, which affects more than 1 in 10 persons globally. METHODS: We conducted exome sequencing and diagnostic analysis in two cohorts totaling 3315 patients with chronic kidney disease. We assessed the diagnostic yield and, among the patients for whom detailed clinical data were available, the clinical implications of diagnostic and other medically relevant findings. RESULTS: In all, 3037 patients (91.6%) were over 21 years of age, and 1179 (35.6%) were of self-identified non-European ancestry. We detected diagnostic variants in 307 of the 3315 patients (9.3%), encompassing 66 different monogenic disorders. Of the disorders detected, 39 (59%) were found in only a single patient. Diagnostic variants were detected across all clinically defined categories, including congenital or cystic renal disease (127 of 531 patients [23.9%]) and nephropathy of unknown origin (48 of 281 patients [17.1%]). Of the 2187 patients assessed, 34 (1.6%) had genetic findings for medically actionable disorders that, although unrelated to their nephropathy, would also lead to subspecialty referral and inform renal management. CONCLUSIONS: Exome sequencing in a combined cohort of more than 3000 patients with chronic kidney disease yielded a genetic diagnosis in just under 10% of cases. (Funded by the National Institutes of Health and others.).

Impact of positive preoperative urine cultures before pediatric lower urinary tract reconstructive surgery.

PURPOSE: Children who undergo lower urinary tract reconstruction (LUTR) often have asymptomatic bacteriuria or recurrent urinary tract infections (UTI). We aimed to determine the prevalence of positive preoperative urine cultures (PPUC) before LUTR and to analyze any impact on postoperative outcomes. METHODS: This retrospective review included all pediatric LUTR procedures utilizing bowel segments performed by one surgeon over 2 years. Preoperative cultures were obtained 1-2 days before surgery. Baseline characteristics and 90-day infection/readmission rates between patients with and without PPUC were compared using descriptive statistics, Fisher's exact, and Mann-Whitney tests with significance p < 0.05. RESULTS: 54 patients with mean age 10.1 ± 5.6 years underwent LUTR procedures using bowel including continent catheterizable channel (85%), enterocystoplasty (81%), and/or urinary diversion (9%). PPUC was present in 28 patients (52%). Postoperatively, 20% had inpatient infections, including eight UTI, four surgical site infections, and two bloodstream infections with no difference between those with or without PPUC. Within 90 days of discharge, 28% of patients were readmitted to the hospital, and there was no difference between groups. Postoperative urine cultures were positive in 83% of patients within 90 days. CONCLUSIONS: Half of the patients undergoing LUTR have PPUC, but it does not increase the risk of postoperative infections or hospital readmissions. We believe complex LUTR can be safely performed in patients with PPUC.

A Convex Hull-Based New Metric for Quantification of Bladder Wall Irregularity in Pediatric Patients With Congenital Anomalies of the Kidney and Urinary Tract.

OBJECTIVES: Early identification and quantification of bladder damage in pediatric patients with congenital anomalies of the kidney and urinary tract (CAKUT) is crucial to guiding effective treatment and may affect the eventual clinical outcome, including progression of renal disease. We have developed a novel approach based on the convex hull to calculate bladder wall trabecularity in pediatric patients with CAKUT. The objective of this study was to test whether our approach can accurately predict bladder wall irregularity. METHODS: Twenty pediatric patients, half with renal compromise and CAKUT and half with normal renal function, were evaluated. We applied the convex hull approach to calculate T, a metric proposed to reflect the degree of trabeculation/bladder wall irregularity, in this set of patients. RESULTS: The average T value was roughly 3 times higher for diseased than healthy patients (0.14 [95% confidence interval, 0.10-0.17] versus 0.05 [95% confidence interval, 0.03-0.07] for normal bladders). This disparity was statistically significant (P < .01). CONCLUSIONS: We have demonstrated that a convex hull-based procedure can measure bladder wall irregularity. Because bladder damage is a reversible precursor to irreversible renal parenchymal damage, applying such a measure to at-risk pediatric patients can help guide prompt interventions to avert disease progression.

Sonographic Prediction of Pediatric Renal Scarring With Full Parameter Normalization.

OBJECTIVES: To predict the chronic kidney disease (CKD) state for pediatric patients based on scaled renal cortical echogenicity. METHODS: Sonograms from a cohort of 26 patients, half of whom had stage 4 or 5 CKD, whereas the other half had normal renal function, were analyzed. For each patient image, a region of interest (ROI) was drawn around the renal cortex for comparison with an ROI drawn around the hepatic parenchyma. The latter ROI was shifted spatially to normalize the signal attenuations and time-gain compensations of the two organs' ROIs. Then the average pixel intensity of the renal ROI was divided by the corresponding hepatic value, resulting in scaled renal cortical echogenicity. RESULTS: The average scaled renal cortical echogenicity was higher for diseased than healthy kidneys by roughly a factor of 2 (2.01 [95% confidence interval, 1.62-2.40] versus 1.05 [95% confidence interval, 0.88-1.23] for normal kidneys). This difference was statistically significant (P < .001). CONCLUSIONS: Our results show that the pediatric CKD state correlates with rigorously calculated scaled renal cortical echogenicity.

The association of the severity of anorectal malformations and intestinal malrotation.

INTRODUCTION: Intestinal malrotation is a known association of anorectal malformations (ARM). Exact incidence, prognosis and surgical implications related to ARM are unknown. The aim of this study was to identify relevant associations between ARM and the presence of malrotation. METHODS: Records of patients from two referral centers were retrospectively analyzed looking for malrotation associated to ARM and its management, as well as factors for functional prognosis. RESULTS: 40 patients out of 2572 with ARM (1.6%) were found to have malrotation. Females were more commonly affected, and severe malformations were more frequent (cloaca, covered cloacal exstrophy in females and rectoprostatic and rectobladder neck fistula in males). Factors significantly associated with malrotation included Müllerian or Wolffian duct anomalies (P<0.05), while fecal continence status, presence of constipation, and use of laxatives or enemas were not. Detecting and correcting malrotation early on or at the time of colostomy creation represented a protective factor against additional surgeries for bowel obstruction and volvulus (P<0.001). Removal of the appendix during malrotation treatment required constructing a neoappendicostomy using a cecal flap in 9 out of 14 patients needing antegrade enema administration. CONCLUSIONS: Malrotation presence in patients with ARM has the same frequency as in the general population, but it is more common in severe malformations. Surgeons treating these patients should address the malrotation at the time of colostomy opening if detected. The appendix should be preserved for potential future use as an appendicostomy for antegrade administration of enemas.

Serum cystatin C as a novel marker to differentiate pseudoazotemia in the setting of intraperitoneal urine extravasation.

Urinary ascites results in pseudoazotemia due to urinary creatinine reabsorption across the peritoneum. We report a case of a pyeloplasty complicated by urine extravasation, in which the diagnosis was aided by discrepant findings of an elevated serum creatinine level but a stable cystatin C level. Cystatin C is a marker of renal function but is not typically excreted into the urine and therefore can be used to differentiate pseudoazotemia from true azotemia and is a better marker of renal function in the setting of known urinary ascites. These findings are relevant for patients with potential traumatic or nontraumatic sources of urine extravasation.

Endoscopic treatment with dextranomer/hyaluronic acid for persistent incontinence after continent urinary reconstruction.

PURPOSE: To determine the applicability and long-term outcome of endoscopic injection of dextranomer/hyaluronic acid (Dx/HA) to correct incontinence in patients who had previously undergone continent urinary reconstruction. PATIENTS AND METHODS: A retrospective cohort study was performed of all patients who underwent Dx/HA injection at our institution from January 2001 to June 2011. All patients had adequate bladder capacity and compliance on maximized medical therapy before injection. "Success" was defined as either "continence" (daytime dry interval >3 hours) or "improvement" (daytime dry interval >2 hours). RESULTS: A total of 22 children (16 females and 6 males) had Dx/HA injections for persistent incontinence from either bladder neck (7), Mitrofanoff (10), or both (5). Median age at injection was 13 years (range 4-21). Children underwent an average of 1.6 injection sessions per patient with an average of 2.6 mL of Dx/HA per session. At a median follow-up of 72 months (range 4-104), 19 (86.4%) patients had successful results (16 continent, 3 improved). For those incontinent from bladder neck, 42% became continent after 1, 75% after 2, and 83% after 3 injections, with a success rate of 91% (10 continent, 1 improved). For those incontinent from Mitrofanoff, 20% became continent after 1, and 73% after 2 injections, with a success rate of 86% (11 continent, 2 improved). CONCLUSIONS: Endoscopic injection of Dx/HA to correct residual incontinence in selected children after urinary reconstruction appears to be safe and effective, achieving a dry interval in more than two-thirds of patients.

Epididymitis in patients with anorectal malformations: a cause for urologic concern.

INTRODUCTION: Epididymitis in patients with anorectal malformation (ARM) represents a unique problem because unlike the general population, an underlying urinary tract problem is frequently identified. We review our experience with epididymitis in ARM population with an emphasis on examining urologic outcomes. MATERIALS AND METHODS: We performed a retrospective review of male patients with ARM cared for from 1980 to 2010. Clinical and pathologic variables recorded included age at presentation, recurrence, associated urologic anomalies, incidence of ureteral fusion with mesonephric ductal structures, glomerular filtration rate and urodynamic parameters. RESULTS: Twenty-six patients were identified with documented episodes of epididymitis. Renal injury was noted in five patients (19%), all of whom were diagnosed with neurogenic bladder (NGB) several years after anorectoplasty. NGB was found in ten patients (38%) in our series. Ectopic insertion of ureter into a mesonephric ductal structure was discovered in five patients (19%). Twelve patients (46%) had recurrent episodes of epididymitis, with seven of these patients (58%) being diagnosed with NGB. Two patients in the pubertal group presented with a history of epididymitis and complained of ejaculatory pain. CONCLUSION: Epididymitis in a patient with ARM warrants a comprehensive urologic investigation, particularly in recurrent episodes. Attempts at surgical intervention (e.g. vasectomy) should be avoided until functional assessment of the urinary tract has occurred. Failure to recognize this association may lead to potentially avoidable complications and morbidity. Long term urological follow up of these patients is warranted to identify at risk patients and minimize renal deterioration.

Epididymitis in Patients with Anorectal Malformations: A Cause for Urologic Concern

Introduction Epididymitis in patients with anorectal malformation (ARM) represents a unique problem because unlike the general population, an underlying urinary tract problem is frequently identified. We review our experience with epididymitis in ARM population with an emphasis on examining urologic outcomes. Materials and Methods We performed a retrospective review of male patients with ARM cared for from 1980 to 2010. Clinical and pathologic variables recorded included age at presentation, recurrence, associated urologic anomalies, incidence of ureteral fusion with mesonephric ductal structures, glomerular filtration rate and urodynamic parameters. Results Twenty-six patients were identified with documented episodes of epididymitis. Renal injury was noted in five patients (19%), all of whom were diagnosed with neurogenic bladder (NGB) several years after anorectoplasty. NGB was found in ten patients (38%) in our series. Ectopic insertion of ureter into a mesonephric ductal structure was discovered in five patients (19%). Twelve patients (46%) had recurrent episodes of epididymitis, with seven of these patients (58%) being diagnosed with NGB. Two patients in the pubertal group presented with a history of epididymitis and complained of ejaculatory pain. Conclusion Epididymitis in a patient with ARM warrants a comprehensive urologic investigation, particularly in recurrent episodes. Attempts at surgical intervention (e.g. vasectomy) should be avoided until functional assessment of the urinary tract has occurred. Failure to recognize this association may lead to potentially avoidable complications and morbidity. Long term urological follow up of these patients is warranted to identify at risk patients and minimize renal deterioration .

Creation of an appendicovesicostomy Mitrofanoff from a preexisting appendicocecostomy utilizing the spilt appendix technique.

Continent catheterizable channels have revolutionized reconstructive surgery to achieve both urinary and fecal continence. The Mitrofanoff and Malone antegrade continent catheterizable channels offer improved quality of life relative to permanent incontinent stomas. A frequently employed surgical option for creating a Mitrofanoff when an existing appendicocecostomy exists involves harvesting a separate piece of intestine. If however the Malone has preceded the creation of a Mitrofanoff, we describe a surgical technique that may avoid the need for a bowel harvest and resultant anastomosis. We report our series of patients utilizing a novel alternative strategy in the select clinical circumstance of an existing appendicocecostomy to expand the armamentarium of the urologic reconstructive surgeon.

Pediatric varicocelectomy: a comparative study of conventional laparoscopic and laparoendoscopic single-site approaches.

BACKGROUND AND PURPOSE: Laparoscopy is a common approach to manage varicoceles in both the adult and pediatric population. The purpose of this study is to report our experience and compare outcomes between conventional laparoscopy and laparoendoscopic single-site (LESS) surgery for varicocelectomy in the pediatric population. PATIENTS AND METHODS: A retrospective cohort study was performed of all patients who underwent conventional laparoscopic varicocelectomy (LV) and laparoendoscopic single-site varicocelectomy (LESSV) at a single pediatric institution from December 2007 to March 2012. Patient demographics, intraoperative details, narcotic use, and complications were reviewed. RESULTS: LV was performed in 32 patients and LESSV in 11 patients. None had conversion to open surgery. Median age was 16 years for LV (range 12-23) and 15 years for LESSV (range 12-20), P=0.061. Median operative time was 55 minutes for LV (range 28-90) and 46 minutes for LESSV (range 33-59), P=0.037. Nine (81.8%) patients in the LESSV group and 10 (31.2%) patients in the LV group were administered narcotics in the recovery room, P=0.005. One (3.1%) patient in the LV group was administered ketorolac in the recovery room, P=1. Five patients in each group, LESSV (45.5%) and LV (15.6%), received acetaminophen in the recovery room, P=0.092. All procedures were performed on an outpatient basis except for one because of a concomitant procedure. Median follow-up was 22 months in LV and 15 months in LESSV, P=0.015. One (3.1%) postoperative hydrocele was noted after LV and 1 (9.1%) after LESSV, P=0.451. All varicoceles were clinically resolved in both groups. CONCLUSIONS: LESSV is comparable to LV in the pediatric population. Our initial experience indicates that the LESS approach may be more painful in the immediate postoperative period than conventional laparoscopy. The LESS technique warrants further evaluation to determine if one approach is clearly more advantageous.

Complexities of gender assignment in 17ß-hydroxysteroid dehydrogenase type 3 deficiency: is there a role for early orchiectomy?

BACKGROUND: 17ß-Hydroxysteroid dehydrogenase type-3 (17ßHSD-3) deficiency is a rare cause of 46,XY disorders of sex development. The enzyme converts androstenedione to testosterone, necessary for masculinization of male genitalia in utero. 17ßHSD-3 deficiency is frequently diagnosed late, at puberty, following virilization, with consequent female-to-male gender reassignment in 39-64%. The decision for sex of rearing is difficult, especially if diagnosed in early childhood. Consensus guidelines are equivocal or support male gender assignment. Long-term outcomes data to guide decisions are also lacking; however, in the few cases of early diagnosis and orchiectomy, female gender retention appears more likely.We report two patients with 17ßHSD-3 deficiency, who presented at unusual ages, in whom female gender was chosen. We performed a focused literature review and summary of gender outcomes in 17ßHSD-3 deficiency following early orchiectomy. CASES: Patient A was a phenotypic female who presented at one year of age with bilateral inguinal hernias and external female genitalia. Testes were identified at surgery. The karyotype was 46,XY. She was initially diagnosed with complete androgen insensitivity syndrome; however, androgen receptor mutation analysis was negative. Human chorionic gonadotropin stimulation yielded a low testosterone: androstenedione ratio (0.6, normal >0.8). Genetic testing demonstrated compound heterozygosity for two known mutations of the HSD17B3 gene. She underwent bilateral orchiectomy at two years of age.Patient B was born with female genitalia and virilized at 13 years of age. She did not seek evaluation until 22 years of age. Her karyotype was 46,XY. She had bilateral inguinal testes and low testosterone: androstenedione ratio (0.3). HSD17B3 gene sequencing showed her to be a compound heterozygote for two known mutations. She identified herself as female and underwent bilateral orchiectomy and estrogen replacement therapy. CONCLUSIONS: These two patients highlight the complexities of diagnosis and management in 17ßHSD-3 deficiency. Although existing data are limited, early orchiectomy is likely to result in retention of female gender identity, avoiding the complications related to virilization in adolescence. As such, it is important to pursue a definitive diagnosis to guide clinical decisions, and to have the support and long term follow up with an inter-disciplinary disorders of sex development team.

Urologic co-morbidities associated with sacrococcygeal teratoma and a rational plan for urologic surveillance.

BACKGROUND: Sacrococcygeal teratoma (SCT) is one of the most common neonatal and fetal tumors. SCT pelvic mass effect and the need for aggressive surgical resection, create potential for urologic co-morbidity. We reviewed our experience with SCTs and propose a rational plan for urologic surveillance. METHODS: We retrospectively reviewed all patients with SCT evaluated at our institution from 2004 to 2011. We collected data on the need for reconstructive surgery related to the urologic co-morbidity, the time to detection of urologic co-morbidity, and length of follow-up. RESULTS: We identified 28 patients evaluated during the study period with a median follow-up of 3.1 year (range 0.14-13.4). The Altman classifications were--type I: 7 (25%), II: 15 (53.6%), and III: 6 (21.4%). Eighteen (64.3%) patients had an associated urologic co-morbidity: 12 (42.9%) patients had hydronephrosis, VUR--10 (35.7%), NGB--13 (46.4%), and 4 (14.3%) developed ≥CKD2. When comparing the patients according to Altman classification, there was a trend towards more urologic co-morbidity in patients with increasing pelvic involvement, P = 0.06. Eleven patients (39.3%) had delayed urologic evaluation and five (17.9%) required reconstructive urologic surgery. In comparing these groups, 4 of 11 (36.4%) undergoing delayed urologic evaluation progressed to reconstruction, as opposed to only one of 17 (5.7%) with urologic evaluation within first year of life (P-value = 0.06). CONCLUSION: Urologic co-morbidities are common in children with SCT and appear most common in patients with more pelvic tumor involvement (≥Altman II). A risk-adapted approach to urologic surveillance is proposed.

Renal rhabdomyosarcoma in a pancake kidney.

Renal rhabdomyosarcoma (RMS) is a rare pediatric tumor. Pancake kidneys are unusual anatomic anomalies resulting when both upper and lower poles of the embryonic kidney become fused. We report on a 4-year-old boy who was discovered to have a stage 4, group IV renal embryonal RMS arising from a pancake kidney with metastases to the lung, pelvis, and bone marrow. Treatment included multimodal therapy, consisting of neoadjuvant chemotherapy, complete surgical resection, and adjuvant chemotherapy. He remains in clinical remission 7 months after resection.

Prenatal and postnatal urologic complications of sacrococcygeal teratomas.

PURPOSE: Urologic complications are an underappreciated sequelae of the mass effect of sacrococcygeal teratoma (SCT) and its resection. The goal of this study was to evaluate the incidence and severity of urologic complications in patients with SCT. METHODS: A retrospective review of patients with a prenatal diagnosis of SCT and postnatal referral for SCT at a single institution during a 5-year period (2004-2009) was performed. The presence of prenatal and postnatal urologic abnormalities were collected and analyzed. RESULTS: Thirty patients were identified for inclusion in the study. Twenty-two patients were diagnosed prenatally, 3 patients were referred for resection of the tumor, and 5 patients were initially treated elsewhere and referred after resection for urologic complications. Of the 20 patients with subsequent follow-up included in this study, 9 had neurogenic bladder, 5 of whom also had associated renal injury. All patients with renal injury had a higher grade Altman type II/III lesion. CONCLUSION: Urologic problems appear to be common in patients with SCT. Higher grade SCTs should alert the surgeon to possible urologic sequelae, particularly neurogenic bladder and renal injury. Careful urologic evaluation and management of the genitourinary tract should be included in prenatal and preoperative counseling.

Acquired posterior urethral diverticulum following surgery for anorectal malformations.

PURPOSE: Despite significant advances in the surgical management of anorectal malformations (ARMs), many children still experience significant debilities from potentially avoidable complications. One complication, the posterior urethral diverticulum, may have untoward consequences if not recognized and treated. METHODS: A retrospective cohort review was undertaken of male patients who presented to us with persistent problems after being operated on elsewhere for ARM. Twenty-nine patients presented with a urethral diverticulum. Their charts were reviewed for the type of malformation, prior repair, presentation, treatment, and postoperative follow-up. RESULTS: Twenty-nine patients were identified that fit the criteria for this study. To date, 28 patients have been managed with reoperation. Urinary complaints were the most common presenting symptoms. All patients were repaired using a posterior sagittal approach. Pathology of the diverticulum in one patient revealed a well-differentiated mucinous adenocarcinoma. CONCLUSION: The incidence of acquired posterior urethral diverticulum has decreased with the popularization of the posterior sagittal incision. There is a theoretical concern that the incidence may increase with the use of laparoscopy for the treatment of ARMs especially those where the fistula is below the peritoneal reflection. Once detected, the diverticulum should be excised.

Low incidence of urinary tract infections following renal transplantation in children with bladder augmentation.

PURPOSE: Children with end-stage renal disease and bladder dysfunction may require augmentation cystoplasty before kidney transplantation. Previous reports have suggested unacceptable urinary tract infection rates in these immunosuppressed patients. We reviewed our experience in this population. MATERIALS AND METHODS: We retrospectively studied patients undergoing augmentation cystoplasty and subsequent renal transplantation by a single surgeon between 1989 and 2007. This cohort was compared with a control group on clean intermittent catheterization who had undergone transplantation without augmentation. Patient demographics, etiology of renal failure, surgical details, surgical/allograft outcomes and occurrence of urinary tract infection were analyzed. RESULTS: The augmented group included 17 patients with a median age at reconstruction of 6.4 years. Stomach was used in 15 patients and colon in 2. Median time between reconstruction and transplantation was 1.2 years. Median followup after transplantation was 7.7 years. The control group included 17 patients with a median age at transplantation of 10.9 years. Median followup in the controls was 6.1 years. All ureteral reimplantations were antirefluxing. Patients on clean intermittent catheterization were maintained on oral antibiotic suppression and/or gentamicin bladder irrigations. In the augmented group 35 episodes of urinary tract infection were noted, and the number of documented infections per patient-year of followup was 0.22, compared to 32 episodes of urinary tract infection and 0.28 infections per patient-year of followup in the controls. No allograft was lost to infectious complications. CONCLUSIONS: In our series there was no increase in urinary tract infection rate following renal transplantation in patients with augmented bladders compared to controls. This finding may be due to the use of gastric augmentation, antirefluxing reimplantation and gentamicin irrigations.

MRI of acquired posterior urethral diverticulum following surgery for anorectal malformations.

BACKGROUND: Posterior urethral diverticulum (PUD) is one of the most common postoperative complications associated with anorectal malformation (ARM) correction. OBJECTIVE: To describe our MRI protocol for evaluating acquired PUD following ARM surgery, and associated imaging findings. MATERIALS AND METHODS: Two radiologists retrospectively reviewed 61 pelvic MRI examinations performed for postoperative ARM for PUD identification and characteristics. Associated clinical, operative and cystoscopy reports were also reviewed and compared to MRI. RESULTS: An abnormal retrourethral focus suspicious for PUD was identified at MRI in 13 patients. Ten of these patients underwent subsequent surgery or cystoscopy, and PUD was confirmed in five. All of the confirmed PUD cases appeared as cystic lesions that were at least 1 cm in diameter in two imaging planes. Four of the false-positive cases were punctate retrourethral foci that were visible only on a single MRI plane. One patient had a seminal vesical cyst mimicking a PUD. CONCLUSION: Pelvic MRI can be a useful tool in the postoperative assessment of suspected PUD associated with ARM. Radiologists should have a high clinical suspicion for a postoperative PUD when a cystic lesion posterior to the bladder/posterior urethra is encountered on two imaging planes in these patients.