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Antenatal hydroureteronephrosis presenting as an apparent solid renal mass
CASE REPORT
ANTENATAL HYDROURETERONEPHROSIS PRESENTING AS AN APPARENT SOLID RENAL MASS C. D. ANTHONY HERNDON
AND
MARK P. CAIN
ABSTRACT We present a patient with an apparent renal mass that was identified antenatally with pyelocaliectasis and ureterectasis. A right ectopic ureter with an apparent cystic upper pole was eventually confirmed at 5 months of age. The definitive diagnosis in this case eluded an initial exhaustive neonatal radiologic and surgical evaluation. UROLOGY 62: 144i–144iii, 2003. © 2003 Elsevier Inc.
T
he antenatal detection of a duplex renal collecting system occurs with a frequency of 1:70 to 500 pregnancies. Antenatal sonography represents the most frequent method used to diagnosis this entity.1 The introduction of fetal sonography has not altered the natural history of the duplex system in terms of its predictive ability to differentiate patients who eventually manifest symptoms or its ability to discriminate salvageable upper pole function. The postnatal evaluation of a duplex collecting system should include thorough radiologic surveillance, including renal sonography, voiding cystography, and radionuclide imaging.2 We present a patient with a duplex collecting system that initially eluded an exhaustive postnatal evaluation. CASE REPORT A G1P0 26-year-old mother was referred from an outlying hospital with a screening fetal ultrasound scan that demonstrated fetal right pelvocaliectasis. A level III fetal ultrasound scan performed at 23.5 weeks revealed right Society for Fetal Urology (SFU) grade III pelvocaliectasis (anteroposterior 19 mm), right ureterectasis, a normal left collecting system and urinary bladder, and a normal amPresented at the Society for Fetal Urology Meeting in Orlando, Florida, May 25, 2002. From the Department of Urology, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, Indiana Address for correspondence: C. D. Anthony Herndon, M.D., Department of Urology, Riley Hospital for Children, 702 Barnhill Drive, No. 1739, Indianapolis, IN 46202 Submitted: July 9, 2002, accepted (with revisions): October 11, 2002 © 2003 ELSEVIER INC. ALL RIGHTS RESERVED
niotic fluid index. Female sex was confirmed. The remainder of the organ system evaluation was unremarkable. The maternal family history was negative for renal disease. At 30 weeks, a third, level III ultrasound scan demonstrated an enlarged right kidney with a length of 5.76 cm, an anteroposterior pelvis of 1.12 cm, and a ureter of 1.11 cm (Fig. 1). These findings remained consistent through 37 weeks’ gestation. After an uneventful delivery with Apgar scores of 9 and 9 (at 1 and 5 minutes), the urinary tract was evaluated on the first day of life with renal ultrasonography. The renal ultrasound scan revealed an echogenic mass in the upper pole of the right kidney that measured 3.6 cm by 3.4 cm with a longitudinal length of 6.7 cm. Right pelvocaliectasis was not detected. A normal right adrenal gland was identified. The left kidney measured 4.3 cm without pelvocaliectasis and the urinary bladder was unremarkable. After the renal ultrasound scan, a MAG-3 Lasix washout scan revealed an enlarged right kidney with decreased function in the upper pole of the right kidney (deferential function 40%). At 2 days of age, a computed tomography scan demonstrated a 4.5-cm lobulated solid mass in the upper pole of the right kidney with peripheral cysts (Fig. 2). Central enhancement did not occur, although peripheral enhancement was present. The mass was well circumscribed and did not invade the liver or abdominal wall. The lower pole of the right and left kidney was unremarkable. Voiding cystourethrography confirmed grade II right reflux into the lower pole of an apparent single-system right kidney that was displaced secondary to the renal mass. The patient was taken to the operating room with a presumptive diagnosis of an infiltrative renal 0090-4295/03/$30.00 doi:10.1016/S0090-4295(02)02379-8 144i
FIGURE 1. Antenatal ultrasound scan at 30 weeks’ gestation demonstrating right renal hypertrophy (long arrow), pelvocaliectasis (arrowhead), and ureterectasis (short arrow).
FIGURE 2. Computed tomography scan demonstrating cystic mass involving the upper pole of the right kidney (arrow).
mass that was suspicious for either a Wilms’ tumor variant or congenital mesoblastic nephroma. Frozen section biopsy analysis revealed autosomal dominant polycystic kidney disease (Fig. 3). The patient was closed, and her recovery was uneventful. A repeat renal ultrasound scan at 5 months of age demonstrated new-onset right SFU grade I pelviectasis, ureterectasis that originated from the cystic mass, and a dilated distal ureter posterior to the bladder. Additionally, the left kidney demonstrated SFU grade I pelviectasis. At 6 months of age, the patient remained asymptomatic while receiving prophylactic antibiotics.
COMMENT The detection of pelvocaliectasis is the most common antenatal urologic finding and occurs in 144ii
FIGURE 3. Hematoxylin-eosin stain of renal biopsy demonstrating cyst throughout kidney involving glomeruli (long arrow), proximal tubule (arrowhead), and distal tubule (short arrow).
approximately 1% of all pregnancies.3 Although fetal sonography appears to be sensitive, it is not a powerful predictor of postnatal pathology findings. Frequently, the degree of hydronephrosis, laterality, and accompanying ureteral dilation change throughout the pregnancy. Observation with serial bladder cycling has been suggested in an effort to arrive at a more consistent longitudinal antenatal picture. Nonetheless, ultrasonography remains a reliable and inexpensive method to identify urologic pathology features. A systematic postnatal radiologic evaluation confirms the diagnosis in most cases. After the first postnatal imaging studies, our patient demonstrated right renal asymmetry and a cystic renal mass that was initially confirmed by the pathologist on frozen section analysis as autosomal dominant polycystic kidney disease. The definitive diagnosis of a right ectopic ureter with a duplex renal collecting system was made at 5 months of age after repeated upper tract imaging studies. Unilateral cystic renal disease is a well-described entity in the infant population and includes unilateral autosomal dominant polycystic kidney disease,4,5 unilateral renal cystic disease,6 – 8 cystic Wilms’ tumor, or congenital mesoblastic nephroma. In situations that involve cystic dysplasia with an associated shell of tissue corresponding to the upper pole, the diagnosis of ectopic ureter should be considered. Radiographic imaging may facilitate the diagnosis, but, as our case demonstrated, open renal biopsy may be required. We elected to leave the cystic mass in place on the basis of the frozen section biopsy finding of autosomal polycystic kidney disease in effort to preserve future renal function. The current indication for cyst removal or decortication in patients with autosomal polycystic kidney disease is infection and pain. Retrograde cystograUROLOGY 62 (1), 2003
phy is discouraged because of the risk of cyst infection. These patients are not at an increased risk of malignancy; therefore, elective nephrectomy is not indicated. At 23.5 weeks, our patient presented with an enlarged kidney and dilation of the renal pelvis and ureter. The classic antenatal features representative of a duplex collecting system include two distinct renal pelves, a cystic mass confined to the upper pole, and a dilated ureter with or without the presence of a ureterocele. The antenatal finding of a ureterocele represents a powerful predictor of the postnatal finding of a duplex renal collecting system.9 The initial antenatal findings in this case were consistent throughout pregnancy, and ureteral dilation represented the only finding consistent with a duplex system. The antenatal detection of a duplex renal collecting system does not appear to alter the natural history of the disease, but it does allow earlier evaluation and intervention. Antenatal ultrasonography has not demonstrated the ability to discriminate those patients who will eventually manifest symptoms, nor can it predict those patients who will have salvageable upper pole function.10,11 The antenatal identification allows the early institution of antibiotic prophylaxis and gives the surgeon the opportunity to intervene electively before symptom development. In the present case, if the diagnosis of an ectopic ureter of a duplex collecting system with poor function in the upper pole moiety had been made initially, an upper pole partial nephrectomy would have been performed.
UROLOGY 62 (1), 2003
CONCLUSIONS We present a common urologic finding that was unique in its presentation in both the antenatal and the postnatal period. Although a thorough evaluation was performed, the definitive diagnosis was not made until 5 months of age. REFERENCES 1. Thomas DFM: Fetal uropathy. Br J Urol 66: 225–231, 1990. 2. Whitten SM, and Wilcox DT: Duplex systems. Prenat Diagn 21: 952–957, 2001. 3. Elder JS: Antenatal hydronephrosis: fetal and neonatal management. Pediatr Clin North Am 44: 1299 –1321, 1997. 4. Strand WR, Rushton HG, Markle BM, et al: Autosomal dominant polycystic kidney disease in infants: asymmetric disease mimicking a unilateral renal mass. J Urol 141: 1151– 1153, 1989. 5. Sheu JN, Chen CH, Tsau YK, et al: Autosomal dominant polycystic kidney disease: an unusual presentation as unilateral renal mass in the infant. Am J Nephrol 11: 252–256, 1991. 6. Kohno A, and Yunoki M: Unilateral renal cystic disease. Radiat Med 17: 423–426, 1999. 7. Middlebrook PF, Nizalik E, and Schillinger JF: Unilateral renal cystic disease: a case presentation. J Urol 148: 1221– 1223, 1992. 8. Hwang DY, Ahn C, Lee JG, et al: Unilateral renal cystic disease in adults. Nephrol Dial Transplant 14: 1999 –2003, 1999. 9. Abuhamad AZ, Horton CE Jr, Horton SH, et al: Renal duplication anomalies in the fetus: clues for prenatal diagnosis. Ultrasound Obstet Gynecol 7: 174 –177, 1996. 10. Hulbert WC, and Rabinowitz R: Prenatal diagnosis of duplex system hydronephrosis: effect on renal salvage. Urology 51(suppl 5A): 23–26, 1998. 11. Van Savage JG, and Mesrobian HJ: The impact of prenatal sonography on the morbidity and outcome of patients with renal duplication anomalies. J Urol 153: 768 –770, 1995.
144iii
ANTENATAL HYDROURETERONEPHROSIS PRESENTING AS AN APPARENT SOLID RENAL MASS C. D. ANTHONY HERNDON
AND
MARK P. CAIN
ABSTRACT We present a patient with an apparent renal mass that was identified antenatally with pyelocaliectasis and ureterectasis. A right ectopic ureter with an apparent cystic upper pole was eventually confirmed at 5 months of age. The definitive diagnosis in this case eluded an initial exhaustive neonatal radiologic and surgical evaluation. UROLOGY 62: 144i–144iii, 2003. © 2003 Elsevier Inc.
T
he antenatal detection of a duplex renal collecting system occurs with a frequency of 1:70 to 500 pregnancies. Antenatal sonography represents the most frequent method used to diagnosis this entity.1 The introduction of fetal sonography has not altered the natural history of the duplex system in terms of its predictive ability to differentiate patients who eventually manifest symptoms or its ability to discriminate salvageable upper pole function. The postnatal evaluation of a duplex collecting system should include thorough radiologic surveillance, including renal sonography, voiding cystography, and radionuclide imaging.2 We present a patient with a duplex collecting system that initially eluded an exhaustive postnatal evaluation. CASE REPORT A G1P0 26-year-old mother was referred from an outlying hospital with a screening fetal ultrasound scan that demonstrated fetal right pelvocaliectasis. A level III fetal ultrasound scan performed at 23.5 weeks revealed right Society for Fetal Urology (SFU) grade III pelvocaliectasis (anteroposterior 19 mm), right ureterectasis, a normal left collecting system and urinary bladder, and a normal amPresented at the Society for Fetal Urology Meeting in Orlando, Florida, May 25, 2002. From the Department of Urology, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, Indiana Address for correspondence: C. D. Anthony Herndon, M.D., Department of Urology, Riley Hospital for Children, 702 Barnhill Drive, No. 1739, Indianapolis, IN 46202 Submitted: July 9, 2002, accepted (with revisions): October 11, 2002 © 2003 ELSEVIER INC. ALL RIGHTS RESERVED
niotic fluid index. Female sex was confirmed. The remainder of the organ system evaluation was unremarkable. The maternal family history was negative for renal disease. At 30 weeks, a third, level III ultrasound scan demonstrated an enlarged right kidney with a length of 5.76 cm, an anteroposterior pelvis of 1.12 cm, and a ureter of 1.11 cm (Fig. 1). These findings remained consistent through 37 weeks’ gestation. After an uneventful delivery with Apgar scores of 9 and 9 (at 1 and 5 minutes), the urinary tract was evaluated on the first day of life with renal ultrasonography. The renal ultrasound scan revealed an echogenic mass in the upper pole of the right kidney that measured 3.6 cm by 3.4 cm with a longitudinal length of 6.7 cm. Right pelvocaliectasis was not detected. A normal right adrenal gland was identified. The left kidney measured 4.3 cm without pelvocaliectasis and the urinary bladder was unremarkable. After the renal ultrasound scan, a MAG-3 Lasix washout scan revealed an enlarged right kidney with decreased function in the upper pole of the right kidney (deferential function 40%). At 2 days of age, a computed tomography scan demonstrated a 4.5-cm lobulated solid mass in the upper pole of the right kidney with peripheral cysts (Fig. 2). Central enhancement did not occur, although peripheral enhancement was present. The mass was well circumscribed and did not invade the liver or abdominal wall. The lower pole of the right and left kidney was unremarkable. Voiding cystourethrography confirmed grade II right reflux into the lower pole of an apparent single-system right kidney that was displaced secondary to the renal mass. The patient was taken to the operating room with a presumptive diagnosis of an infiltrative renal 0090-4295/03/$30.00 doi:10.1016/S0090-4295(02)02379-8 144i
FIGURE 1. Antenatal ultrasound scan at 30 weeks’ gestation demonstrating right renal hypertrophy (long arrow), pelvocaliectasis (arrowhead), and ureterectasis (short arrow).
FIGURE 2. Computed tomography scan demonstrating cystic mass involving the upper pole of the right kidney (arrow).
mass that was suspicious for either a Wilms’ tumor variant or congenital mesoblastic nephroma. Frozen section biopsy analysis revealed autosomal dominant polycystic kidney disease (Fig. 3). The patient was closed, and her recovery was uneventful. A repeat renal ultrasound scan at 5 months of age demonstrated new-onset right SFU grade I pelviectasis, ureterectasis that originated from the cystic mass, and a dilated distal ureter posterior to the bladder. Additionally, the left kidney demonstrated SFU grade I pelviectasis. At 6 months of age, the patient remained asymptomatic while receiving prophylactic antibiotics.
COMMENT The detection of pelvocaliectasis is the most common antenatal urologic finding and occurs in 144ii
FIGURE 3. Hematoxylin-eosin stain of renal biopsy demonstrating cyst throughout kidney involving glomeruli (long arrow), proximal tubule (arrowhead), and distal tubule (short arrow).
approximately 1% of all pregnancies.3 Although fetal sonography appears to be sensitive, it is not a powerful predictor of postnatal pathology findings. Frequently, the degree of hydronephrosis, laterality, and accompanying ureteral dilation change throughout the pregnancy. Observation with serial bladder cycling has been suggested in an effort to arrive at a more consistent longitudinal antenatal picture. Nonetheless, ultrasonography remains a reliable and inexpensive method to identify urologic pathology features. A systematic postnatal radiologic evaluation confirms the diagnosis in most cases. After the first postnatal imaging studies, our patient demonstrated right renal asymmetry and a cystic renal mass that was initially confirmed by the pathologist on frozen section analysis as autosomal dominant polycystic kidney disease. The definitive diagnosis of a right ectopic ureter with a duplex renal collecting system was made at 5 months of age after repeated upper tract imaging studies. Unilateral cystic renal disease is a well-described entity in the infant population and includes unilateral autosomal dominant polycystic kidney disease,4,5 unilateral renal cystic disease,6 – 8 cystic Wilms’ tumor, or congenital mesoblastic nephroma. In situations that involve cystic dysplasia with an associated shell of tissue corresponding to the upper pole, the diagnosis of ectopic ureter should be considered. Radiographic imaging may facilitate the diagnosis, but, as our case demonstrated, open renal biopsy may be required. We elected to leave the cystic mass in place on the basis of the frozen section biopsy finding of autosomal polycystic kidney disease in effort to preserve future renal function. The current indication for cyst removal or decortication in patients with autosomal polycystic kidney disease is infection and pain. Retrograde cystograUROLOGY 62 (1), 2003
phy is discouraged because of the risk of cyst infection. These patients are not at an increased risk of malignancy; therefore, elective nephrectomy is not indicated. At 23.5 weeks, our patient presented with an enlarged kidney and dilation of the renal pelvis and ureter. The classic antenatal features representative of a duplex collecting system include two distinct renal pelves, a cystic mass confined to the upper pole, and a dilated ureter with or without the presence of a ureterocele. The antenatal finding of a ureterocele represents a powerful predictor of the postnatal finding of a duplex renal collecting system.9 The initial antenatal findings in this case were consistent throughout pregnancy, and ureteral dilation represented the only finding consistent with a duplex system. The antenatal detection of a duplex renal collecting system does not appear to alter the natural history of the disease, but it does allow earlier evaluation and intervention. Antenatal ultrasonography has not demonstrated the ability to discriminate those patients who will eventually manifest symptoms, nor can it predict those patients who will have salvageable upper pole function.10,11 The antenatal identification allows the early institution of antibiotic prophylaxis and gives the surgeon the opportunity to intervene electively before symptom development. In the present case, if the diagnosis of an ectopic ureter of a duplex collecting system with poor function in the upper pole moiety had been made initially, an upper pole partial nephrectomy would have been performed.
UROLOGY 62 (1), 2003
CONCLUSIONS We present a common urologic finding that was unique in its presentation in both the antenatal and the postnatal period. Although a thorough evaluation was performed, the definitive diagnosis was not made until 5 months of age. REFERENCES 1. Thomas DFM: Fetal uropathy. Br J Urol 66: 225–231, 1990. 2. Whitten SM, and Wilcox DT: Duplex systems. Prenat Diagn 21: 952–957, 2001. 3. Elder JS: Antenatal hydronephrosis: fetal and neonatal management. Pediatr Clin North Am 44: 1299 –1321, 1997. 4. Strand WR, Rushton HG, Markle BM, et al: Autosomal dominant polycystic kidney disease in infants: asymmetric disease mimicking a unilateral renal mass. J Urol 141: 1151– 1153, 1989. 5. Sheu JN, Chen CH, Tsau YK, et al: Autosomal dominant polycystic kidney disease: an unusual presentation as unilateral renal mass in the infant. Am J Nephrol 11: 252–256, 1991. 6. Kohno A, and Yunoki M: Unilateral renal cystic disease. Radiat Med 17: 423–426, 1999. 7. Middlebrook PF, Nizalik E, and Schillinger JF: Unilateral renal cystic disease: a case presentation. J Urol 148: 1221– 1223, 1992. 8. Hwang DY, Ahn C, Lee JG, et al: Unilateral renal cystic disease in adults. Nephrol Dial Transplant 14: 1999 –2003, 1999. 9. Abuhamad AZ, Horton CE Jr, Horton SH, et al: Renal duplication anomalies in the fetus: clues for prenatal diagnosis. Ultrasound Obstet Gynecol 7: 174 –177, 1996. 10. Hulbert WC, and Rabinowitz R: Prenatal diagnosis of duplex system hydronephrosis: effect on renal salvage. Urology 51(suppl 5A): 23–26, 1998. 11. Van Savage JG, and Mesrobian HJ: The impact of prenatal sonography on the morbidity and outcome of patients with renal duplication anomalies. J Urol 153: 768 –770, 1995.
144iii