Neonatal
Solitary Renal Cysts Associated Posterior Urethral Valves By A. Farkas, M. Firstater,
and J. H. Johnston
Tel Aviv, Israel and Liverpool, 0 Large simple cysts of the kidney are common findings in adults but are extremely rare in neonates. Three cases of large solitary renal cysts in newborn boys associated with posterior urethral valves are described. The pathogenesis, diagnosis, treatment, and differentiation from urinoma secondary to spontaneous urinary extravasation are discussed. INDEX valves.
WORDS:
Neonatal
renal
cyst:
urethral
SEROUS cyst of the kidney T HEfoundSIMPLE commonly in adult life is very seldom observed in children. Less than 30 childhood cases have been reported in the literature.le6 Large simple renal cysts presenting in neonates and presumably, therefore, of congenital origin are exceptionally rare. Seiferth et al.,’ reviewing the literature, recorded only four cases diagnosed and treated under the age of 1 mo. The lesion has been observed in association with severe urethral obstruction and has been reported previously in cases of posterior urethral valves.8-9 Three cases of large congenital simple renal cysts associated with posterior valves are reported herein. Our experience indicates that such cases require diagnostic and therapeutic methods different from those usually considered necessary in the newborn baby with an abdominal mass. CASE
REPORTS
With
England
kidney was displaced to the right side with pelvicalyceal distortion characteristic to an intrarenal mass and that both ureters were elongated, tortuous and dilated (Fig. 1A). Voiding urethrocystography showed posterior urethral valves without vesico-uretric reflux (Fig. I B). The infants abdomen was explored transperitoneally. A large unilocular cyst of the left kidney was found, pushing the kidney to the right. The cyst was uncapped and excised after 450 ml of serous fluid had been aspirated and analysed chemically. Subsequently, transurethral resection of the urethral valves was carried out. Histology showed the cyst wall to be composed of fibrous tissue lined by a single layer of cuboidal epithelium. Radiologic study of the child at the age of 3 yr showed normally positioned kidneys with moderate dilatation of the collecting systems. The bladder outlet and the urethra were normal (Fig. 2A and B). At the age of 7 yr, the boy is in good health and well-developed.
Case
2
D.J., a 3-day-old male baby, was referred to hospital because of a large abdominal mass on the right side. On admission he was found to be ill, with a blood urea of 95 mg/ 100 ml. An excretory urogram failed to visualize either kidney and demonstrated a large soft tissue shadow on the right side (Fig. 3A). Voiding urethrocystography showed the presence of posterior urethral valves with bilateral vesicoureteric reflux (Fig. 3B). The mass, which was thought to be a hydronephrotic kidney. was needled in order to perform an antegrade pyelogram. However, contrast injection demonstrated a large unilocular cyst of the kidney, which was treated by aspiration (Fig. 3C). The aspirate was analyzed chemically and was found to be different from urine. Transurethral resection of the urethral valves was later carried out through a perineal urethrotomy. The baby did well after surgery, but unfortunately died elsewhere at the age of I yr, following a hernia operation.
Case 1 F.S., a lo-day-old male infant, was referred to hospital with dribbling of urine and large mass filling the entire left side of the abdomen. Laboratory investigations, which included urine analysis and blood chemistry, were within normal limits. An excretory pyelogram showed that the left
From
the Departments
Governmental
Medical
cine, Tel-Aviv,
Israel
Liverpool,
and Alder
Governmental
Tel-Aviv,
by Grune & Stratton,
0022-3468/79/1402-0003$01.00/O
132
School of Medi-
Hey Children’s
requests to A. Farkas,
of the Municipal
Weitzman Boulevard, o I979
of the MunicipalHospital,
England.
Address reprint Urology
of Urology
Center and Sackler
Israel. Inc.
Departments Medical
of
Center,
Case
3
C.A., a male newborn, was found immediately after delivery to have a large abdominal mass filling the left side of his abdomen. Within 24 hr he became very ill and toxic. The blood urea rose to I IO mg/ 100 ml, but urine cultures were sterile. High-dose excretory pyelography demonstrated bilateral ureterohydronephrosis. The left kidney was displaced to the right (Fig. 4A). Voiding urethrocystography showed posterior urethral valves with reflux to the left kidney and ureter. The pelvicalyceal system of the left kidney, filled with refluxing contrast medium, showed the characteristic distortion due to a renal mass (Fig. 4B and C). B-scan ultrasonography revealed that the swelling contained fluid. Transurethral resection of the urethral valves was performed at the age of 3 days, using a perineal urethrotomy. Subsequently,
Journal of Pediatric Surgery, Vol. 14, No. 2 (April), 1979
Fig. 1. Case 1 before treatment. (A) Excretory urogrsphy showing contralateral displacement of the left kidney with caiyceal distortion caused by an intrarenal lesion and bilateral ureterohydronephrosis. (6) Voiding urethrocystography demonstrating posterior urethral valves, without reflux.
Fig. 2. Case 1 following excission of renal cyst and endoscopic resection of urethral valves. (A) Excretory urography showing significant improvement of the hydronephrosis and a normal position of the left kidney. (g) Voiding urethrocystography showing normal bladder outlet and urethra.
134
FARKAS.
FIRSTATER,
AND
JOHNSTON
Fig. 3 Case 2. (A) Excretory urography with nonvisualization of both kidneys. A large soft tissue shadow is seen on the right side. (B) Voiding urethrocystography demonstrating posterior urethral valves with bilateral reflux. (C) Right renal cyst punctured and filled with contrast dye. demonstrating a unilocular smooth-walled cavity.
the left flank was punctured and 300 ml of cloudy fluid was aspirated. The aspirate grew Escherichio coli on culture and its chemical composition was different from urine. Contrast injection confirmed the clinical diagnosis of a large simple renal cyst. The cyst was drained by a polyethylene tube for 7 days and the baby recovered rapidly. At the age of 3 mo, pyelography showed persistent bilateral ureterohydronephrosis, but the left kidney had returned to its normal position (Fig. 5A). A voiding urethrocystogram showed spontaneous cure of the left sided reflux and a normal urethra (Fig. 5B). At the age of 1 yr, the child is thriving and renal function tests are normal.
DISCUSSION
The various criteria stressed by DeWeerd and Simon’ for the diagnosis of simple renal cysts in childhood were mostly fullfilled by the three cases reported above. The cysts were unilocular; they did not communicate with the pelvicalyceal system; the renal pelvis and ureter were patent; the affected kidney contained areas of normal parenchyma; and, in the case explored, the cyst had an epithelial lining.
NEONATAL
SOLITARY
RENAL CYSTS
Fig. 4. Case 3 before treatment. (Al Excretory urography showing poor visualization of both kidneys. Left kidney is displaced to the opposite side. (BJ Voiding urethrocystography demonstrating posterior urethal valves with leftside reflux. W Voiding urethrocystography with leftsided reflux, showing calyceal distortion and displacement caused by an intrarenal lesion.
The etiology and pathogenesis of simple renal cysts is disputed, Experimental studies indicate that they might be acquired lesions.“*” Their occurrence, albeit infrequently, in the neonatal period suggests a congenital origin. At any age, they probably develop from the collecting tubules.‘* Including our 3 cases, 7 neonatal simple renal cysts have been reported and it is clear that they are frequently associated with
posterior urethral valves. The latter suggests an etiologic relationship and it has been considered that the cyst may be encapsulated urinoma consequent upon perirenal extravasation.8 We believe, however, that our reported cases were examples of true renal cysts. Chemical analysis of the aspirate in all three cases, compared with urine analysis at the same time, revealed a different urea, creatinine and electrolyte compo-
FARKAS,
FIRSTATER,
AND
JOHNSTON
Case 3 following drainage of the renal cyst and Fig. 5. endoscopic resection of urethral valves. (A) Excretory urography showing good visualization of bilateral ureterohydronephroses. The left kidney has raturned to the normal position. (6) Voiding urethrocystography showing significant improvement in the shape of the posterior urethra and the disappearance of the reflux on the left side.
sition. In case 3, the aspirate was infected while the urine was sterile. The pelvicalyceal distortion, demonstrated radiologically in cases 1 and 3, was characteristic of an intrarenal mass and differed significantly from that caused by extrarenal extravasation. There was contralatera1 displacement of the affected kidney, which could only be caused by fluid under high pressure, as occurs in large serous cysts.” The pressure in a urinoma caused by spontaneous extravasation could not at any time be higher than the pressure in the pelvicalyceal system that caused the urine to extravasate and, therefore, could not cause a significant displacement of the kidney. The epithelial lining found in case 1 makes a clear histologic distinction between a perirenal pseudocyst, which might result from extravasation, and a true simple cyst of the kidney. Differentiation of solid tumors from renal cysts may be made by transfemoral angiography, but this investigation is hazardous in infants because of the possibility of arterial injury and thrombosis.’ An accurate distinction can be made by ultrasonography.‘4-‘6 Percutaneous puncture and aspiration of renal cysts is commonly employed in adults and in our experience and in that of others,‘7*‘s the procedure can
be readily and safely used in infants. We believe that when a renal space-occupying lesion in a newborn is shown to be fluid-containing, operative exploration should be avoided and needle aspiration carried out, both for confirmation of the diagnosis and for treatment. This is particularly so in the sick baby with posterior urethral valves. Infection is a rare, but well-recognized. complication of simple renal cysts; 23 cases, mainly in adult females, have been reported.‘9*20 The suggested etiology of ascending infection is not acceptable in our neonatal case (case 3), since repeated urine cultures were sterile while the cyst cavity contained Auid infected by E. Coli. As the lesion was detected and treated in the first days of life, an intrauterine hematogenous infection is to be suspected, although a careful anamnesis disclosed no infectious disease during pregnancy. The management of an infected simple renal cyst by percutaneous aspiration has been recorded,*’ although usually surgical exploration is required. We believe that our case is the first example of neonatal infected renal cyst reported and treated successfully by percutaneous aspiration.
NEONATAL
SOLITARY
137
RENAL CYSTS
REFERENCES 1. DeWeerd JH, Simon HB: Simple renal cysts in children, review of the literature and report of 5 cases. J Urol 75:912:921, 1956 2. Poole CA, Viamonte M: Unusual renal masses in the pediatric age group. Am J Roentgenol 109:368-379, 1970 3. Ahmed S: Simple renal cysts in childhood. Br J Ural 44:71-75, 1972 4. Redman JF, Scriber LJ, Bisada NK: Simple renal cyst in child. J Pediatr Surg 1 I:1 17-l 18, 1976 5. Holl WH, Delporto GB, Keegan GT, et al: Simple renal cyst in a child. J Ural 115:465466, 1976 6. Garvin DD, Gehring GG, Ball TP: Calcified solitary renal cyst in childhood. J Urol 116:64&645, 1976 7. Seiferth J, Dominick HC, Bulla M, et al: Ein Beitrag zur Klinik der kongenitalen solitaren Nierenzysten. 2 Urol 68:819-825, 1975 8. Williams DI: Urology in childhood, in Williams (DI) ed: Encyclopedia of Urology. Springer, Berlin, 1974, p 76 9. Firstater M, Farkas A: Simple renal cyst in a newborn. Br J Urol45:366-369, 1973 IO. Hepler AB: Solitary cysts of the kidney, a report of 7 cases and observations on the pathogenesis of these cysts. Surg Gynecol Obstet 50:668, 1930 11. Helper AB: Etiology of multilocular cysts of the kidney. J Ural 44:206, 1940
12. Osathanondh V, Potter EL: The pathogenesis of polycystic kidneys. Arch Pathol77:459-502, 1964 13. Byerle P, Lindquist B, Michaelson G: Pressure measurements in renal cysts. Stand J Clin Lab Invest 27:135-138, 1971 14. Hunig R: Ultraschalltomographie am kindlichen abdomen. Helv Pediatr Acta 24:3-22, 1970 (suppl) IS. Lyons EA. Fleming JE, Arnell GC, et al: Nephrosonography in infants and children. Br Med J 2:689%691, 1972 16. Bearman S, Sanders RC, Sing Oh K: B-scan ultrasound in the evaluation of pediatric abdominal masses. Radiology 108:ll l-l 17, 1973 17. Lalli AF: Translumbar pyelography in the child. Pediatrics44:1016-1018, 1969 18. Saxton HM, Cameron JS, Chantler C, et al: Renal puncture in infancy. Br Med J 3:267-270, 1973 19. Limjoco UR, Strauch AE: Infected solitary cyst of the kidney, report of a case and review of the literature. J Urol 961625630, 1966 20. Cho KJ, Maklad N, Curran J, et al: Angiographic and ultrasonic findings in infected simple cysts of the kidney. Am J Roentgen01 127:1015-1019, 1976 21. Stables DP, Jackson RS: Management of an infected simple renal cyst by percutaneous aspiration. Br J Radio] 47:29&292, I974
Solitary Renal Cysts Associated Posterior Urethral Valves By A. Farkas, M. Firstater,
and J. H. Johnston
Tel Aviv, Israel and Liverpool, 0 Large simple cysts of the kidney are common findings in adults but are extremely rare in neonates. Three cases of large solitary renal cysts in newborn boys associated with posterior urethral valves are described. The pathogenesis, diagnosis, treatment, and differentiation from urinoma secondary to spontaneous urinary extravasation are discussed. INDEX valves.
WORDS:
Neonatal
renal
cyst:
urethral
SEROUS cyst of the kidney T HEfoundSIMPLE commonly in adult life is very seldom observed in children. Less than 30 childhood cases have been reported in the literature.le6 Large simple renal cysts presenting in neonates and presumably, therefore, of congenital origin are exceptionally rare. Seiferth et al.,’ reviewing the literature, recorded only four cases diagnosed and treated under the age of 1 mo. The lesion has been observed in association with severe urethral obstruction and has been reported previously in cases of posterior urethral valves.8-9 Three cases of large congenital simple renal cysts associated with posterior valves are reported herein. Our experience indicates that such cases require diagnostic and therapeutic methods different from those usually considered necessary in the newborn baby with an abdominal mass. CASE
REPORTS
With
England
kidney was displaced to the right side with pelvicalyceal distortion characteristic to an intrarenal mass and that both ureters were elongated, tortuous and dilated (Fig. 1A). Voiding urethrocystography showed posterior urethral valves without vesico-uretric reflux (Fig. I B). The infants abdomen was explored transperitoneally. A large unilocular cyst of the left kidney was found, pushing the kidney to the right. The cyst was uncapped and excised after 450 ml of serous fluid had been aspirated and analysed chemically. Subsequently, transurethral resection of the urethral valves was carried out. Histology showed the cyst wall to be composed of fibrous tissue lined by a single layer of cuboidal epithelium. Radiologic study of the child at the age of 3 yr showed normally positioned kidneys with moderate dilatation of the collecting systems. The bladder outlet and the urethra were normal (Fig. 2A and B). At the age of 7 yr, the boy is in good health and well-developed.
Case
2
D.J., a 3-day-old male baby, was referred to hospital because of a large abdominal mass on the right side. On admission he was found to be ill, with a blood urea of 95 mg/ 100 ml. An excretory urogram failed to visualize either kidney and demonstrated a large soft tissue shadow on the right side (Fig. 3A). Voiding urethrocystography showed the presence of posterior urethral valves with bilateral vesicoureteric reflux (Fig. 3B). The mass, which was thought to be a hydronephrotic kidney. was needled in order to perform an antegrade pyelogram. However, contrast injection demonstrated a large unilocular cyst of the kidney, which was treated by aspiration (Fig. 3C). The aspirate was analyzed chemically and was found to be different from urine. Transurethral resection of the urethral valves was later carried out through a perineal urethrotomy. The baby did well after surgery, but unfortunately died elsewhere at the age of I yr, following a hernia operation.
Case 1 F.S., a lo-day-old male infant, was referred to hospital with dribbling of urine and large mass filling the entire left side of the abdomen. Laboratory investigations, which included urine analysis and blood chemistry, were within normal limits. An excretory pyelogram showed that the left
From
the Departments
Governmental
Medical
cine, Tel-Aviv,
Israel
Liverpool,
and Alder
Governmental
Tel-Aviv,
by Grune & Stratton,
0022-3468/79/1402-0003$01.00/O
132
School of Medi-
Hey Children’s
requests to A. Farkas,
of the Municipal
Weitzman Boulevard, o I979
of the MunicipalHospital,
England.
Address reprint Urology
of Urology
Center and Sackler
Israel. Inc.
Departments Medical
of
Center,
Case
3
C.A., a male newborn, was found immediately after delivery to have a large abdominal mass filling the left side of his abdomen. Within 24 hr he became very ill and toxic. The blood urea rose to I IO mg/ 100 ml, but urine cultures were sterile. High-dose excretory pyelography demonstrated bilateral ureterohydronephrosis. The left kidney was displaced to the right (Fig. 4A). Voiding urethrocystography showed posterior urethral valves with reflux to the left kidney and ureter. The pelvicalyceal system of the left kidney, filled with refluxing contrast medium, showed the characteristic distortion due to a renal mass (Fig. 4B and C). B-scan ultrasonography revealed that the swelling contained fluid. Transurethral resection of the urethral valves was performed at the age of 3 days, using a perineal urethrotomy. Subsequently,
Journal of Pediatric Surgery, Vol. 14, No. 2 (April), 1979
Fig. 1. Case 1 before treatment. (A) Excretory urogrsphy showing contralateral displacement of the left kidney with caiyceal distortion caused by an intrarenal lesion and bilateral ureterohydronephrosis. (6) Voiding urethrocystography demonstrating posterior urethral valves, without reflux.
Fig. 2. Case 1 following excission of renal cyst and endoscopic resection of urethral valves. (A) Excretory urography showing significant improvement of the hydronephrosis and a normal position of the left kidney. (g) Voiding urethrocystography showing normal bladder outlet and urethra.
134
FARKAS.
FIRSTATER,
AND
JOHNSTON
Fig. 3 Case 2. (A) Excretory urography with nonvisualization of both kidneys. A large soft tissue shadow is seen on the right side. (B) Voiding urethrocystography demonstrating posterior urethral valves with bilateral reflux. (C) Right renal cyst punctured and filled with contrast dye. demonstrating a unilocular smooth-walled cavity.
the left flank was punctured and 300 ml of cloudy fluid was aspirated. The aspirate grew Escherichio coli on culture and its chemical composition was different from urine. Contrast injection confirmed the clinical diagnosis of a large simple renal cyst. The cyst was drained by a polyethylene tube for 7 days and the baby recovered rapidly. At the age of 3 mo, pyelography showed persistent bilateral ureterohydronephrosis, but the left kidney had returned to its normal position (Fig. 5A). A voiding urethrocystogram showed spontaneous cure of the left sided reflux and a normal urethra (Fig. 5B). At the age of 1 yr, the child is thriving and renal function tests are normal.
DISCUSSION
The various criteria stressed by DeWeerd and Simon’ for the diagnosis of simple renal cysts in childhood were mostly fullfilled by the three cases reported above. The cysts were unilocular; they did not communicate with the pelvicalyceal system; the renal pelvis and ureter were patent; the affected kidney contained areas of normal parenchyma; and, in the case explored, the cyst had an epithelial lining.
NEONATAL
SOLITARY
RENAL CYSTS
Fig. 4. Case 3 before treatment. (Al Excretory urography showing poor visualization of both kidneys. Left kidney is displaced to the opposite side. (BJ Voiding urethrocystography demonstrating posterior urethal valves with leftside reflux. W Voiding urethrocystography with leftsided reflux, showing calyceal distortion and displacement caused by an intrarenal lesion.
The etiology and pathogenesis of simple renal cysts is disputed, Experimental studies indicate that they might be acquired lesions.“*” Their occurrence, albeit infrequently, in the neonatal period suggests a congenital origin. At any age, they probably develop from the collecting tubules.‘* Including our 3 cases, 7 neonatal simple renal cysts have been reported and it is clear that they are frequently associated with
posterior urethral valves. The latter suggests an etiologic relationship and it has been considered that the cyst may be encapsulated urinoma consequent upon perirenal extravasation.8 We believe, however, that our reported cases were examples of true renal cysts. Chemical analysis of the aspirate in all three cases, compared with urine analysis at the same time, revealed a different urea, creatinine and electrolyte compo-
FARKAS,
FIRSTATER,
AND
JOHNSTON
Case 3 following drainage of the renal cyst and Fig. 5. endoscopic resection of urethral valves. (A) Excretory urography showing good visualization of bilateral ureterohydronephroses. The left kidney has raturned to the normal position. (6) Voiding urethrocystography showing significant improvement in the shape of the posterior urethra and the disappearance of the reflux on the left side.
sition. In case 3, the aspirate was infected while the urine was sterile. The pelvicalyceal distortion, demonstrated radiologically in cases 1 and 3, was characteristic of an intrarenal mass and differed significantly from that caused by extrarenal extravasation. There was contralatera1 displacement of the affected kidney, which could only be caused by fluid under high pressure, as occurs in large serous cysts.” The pressure in a urinoma caused by spontaneous extravasation could not at any time be higher than the pressure in the pelvicalyceal system that caused the urine to extravasate and, therefore, could not cause a significant displacement of the kidney. The epithelial lining found in case 1 makes a clear histologic distinction between a perirenal pseudocyst, which might result from extravasation, and a true simple cyst of the kidney. Differentiation of solid tumors from renal cysts may be made by transfemoral angiography, but this investigation is hazardous in infants because of the possibility of arterial injury and thrombosis.’ An accurate distinction can be made by ultrasonography.‘4-‘6 Percutaneous puncture and aspiration of renal cysts is commonly employed in adults and in our experience and in that of others,‘7*‘s the procedure can
be readily and safely used in infants. We believe that when a renal space-occupying lesion in a newborn is shown to be fluid-containing, operative exploration should be avoided and needle aspiration carried out, both for confirmation of the diagnosis and for treatment. This is particularly so in the sick baby with posterior urethral valves. Infection is a rare, but well-recognized. complication of simple renal cysts; 23 cases, mainly in adult females, have been reported.‘9*20 The suggested etiology of ascending infection is not acceptable in our neonatal case (case 3), since repeated urine cultures were sterile while the cyst cavity contained Auid infected by E. Coli. As the lesion was detected and treated in the first days of life, an intrauterine hematogenous infection is to be suspected, although a careful anamnesis disclosed no infectious disease during pregnancy. The management of an infected simple renal cyst by percutaneous aspiration has been recorded,*’ although usually surgical exploration is required. We believe that our case is the first example of neonatal infected renal cyst reported and treated successfully by percutaneous aspiration.
NEONATAL
SOLITARY
137
RENAL CYSTS
REFERENCES 1. DeWeerd JH, Simon HB: Simple renal cysts in children, review of the literature and report of 5 cases. J Urol 75:912:921, 1956 2. Poole CA, Viamonte M: Unusual renal masses in the pediatric age group. Am J Roentgenol 109:368-379, 1970 3. Ahmed S: Simple renal cysts in childhood. Br J Ural 44:71-75, 1972 4. Redman JF, Scriber LJ, Bisada NK: Simple renal cyst in child. J Pediatr Surg 1 I:1 17-l 18, 1976 5. Holl WH, Delporto GB, Keegan GT, et al: Simple renal cyst in a child. J Ural 115:465466, 1976 6. Garvin DD, Gehring GG, Ball TP: Calcified solitary renal cyst in childhood. J Urol 116:64&645, 1976 7. Seiferth J, Dominick HC, Bulla M, et al: Ein Beitrag zur Klinik der kongenitalen solitaren Nierenzysten. 2 Urol 68:819-825, 1975 8. Williams DI: Urology in childhood, in Williams (DI) ed: Encyclopedia of Urology. Springer, Berlin, 1974, p 76 9. Firstater M, Farkas A: Simple renal cyst in a newborn. Br J Urol45:366-369, 1973 IO. Hepler AB: Solitary cysts of the kidney, a report of 7 cases and observations on the pathogenesis of these cysts. Surg Gynecol Obstet 50:668, 1930 11. Helper AB: Etiology of multilocular cysts of the kidney. J Ural 44:206, 1940
12. Osathanondh V, Potter EL: The pathogenesis of polycystic kidneys. Arch Pathol77:459-502, 1964 13. Byerle P, Lindquist B, Michaelson G: Pressure measurements in renal cysts. Stand J Clin Lab Invest 27:135-138, 1971 14. Hunig R: Ultraschalltomographie am kindlichen abdomen. Helv Pediatr Acta 24:3-22, 1970 (suppl) IS. Lyons EA. Fleming JE, Arnell GC, et al: Nephrosonography in infants and children. Br Med J 2:689%691, 1972 16. Bearman S, Sanders RC, Sing Oh K: B-scan ultrasound in the evaluation of pediatric abdominal masses. Radiology 108:ll l-l 17, 1973 17. Lalli AF: Translumbar pyelography in the child. Pediatrics44:1016-1018, 1969 18. Saxton HM, Cameron JS, Chantler C, et al: Renal puncture in infancy. Br Med J 3:267-270, 1973 19. Limjoco UR, Strauch AE: Infected solitary cyst of the kidney, report of a case and review of the literature. J Urol 961625630, 1966 20. Cho KJ, Maklad N, Curran J, et al: Angiographic and ultrasonic findings in infected simple cysts of the kidney. Am J Roentgen01 127:1015-1019, 1976 21. Stables DP, Jackson RS: Management of an infected simple renal cyst by percutaneous aspiration. Br J Radio] 47:29&292, I974
