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Simple Renal Cysts in Children
128) December
THE ,JO:JRNAL OF UT'<.Oi.OGY
Copy:'ight © 1982 by 'I'hs Vlilliam.s & Vhlkins Co.
Printed in U.S.A,
SIMPLE RENAL CYSTS IN CHILDREN STEPHEN A. KRAMER,* ALAN
n
HOFFivlAN, GAZI AYDIN
AND
PANA'i:'OTIS P. KELALIS
From the Departments of Urology and Diagnostic Radiology, Mayo Clinic and Ivlayo Foundation, Rochester, Minnesota
ABSTRACT
Simple :renal in childhood are uncommon and often are confused with duplication anomalies or renal malignancy. A review of 20 children with simple renal cysts at our institution has documented the spectrum of clinical presentations and radiog-taphic findings of this unusual renal mass. Surgical exploration and marsupialization of the cyst wall were done in 12 patients, 4 underwent nephrectomy earlier in our series and 4 have been followed conservatively by ultrasonog-raphy 01· computerized tomography scanning. Although equivocal cases necessitate surgical intervention, we advocate conservative therapy with diagnostic ultrasonography with or without puncture in asymptomatic and normotensive children with simple renal cysts. Simple benign renal cysts in childhood are rare lesions that often are confused with duplication anomalies or renal malignancy. The paucity of reported cases and the variety of radiographic findings often have caused controversy as to the most appropriate management of this renal mass. Herein we review the spectrum of clinical and radiographic presentations in 20 children with simple renal cysts of the kidney, each corresponding to radiographic or histologic criteria defined p:reviously. 1 An approach to the diagnostic evaluation and management of this uncommon renal mass is proposed. MATERIALS AND METHODS
We evaluated 11 and girls with simple renal cysts. The patients ranged in age 9 days to 19 years, with a mean age of 8 years. An abdominal mass was the most frequent clinical presentation, being found in 9 children (table 1), Other signs and symptoms included flank pain, hypertension, enuresis, tract infection, gross hematuria and n...-,c,J-c,...-nna stmction. In l child the renal cyst was m,,grmc:ea film of the kidneys at the time of evaluation of a 0~H"v"'""w. heart defect. hematuria was found at initial µ11s1,e,uca. children had a of tract infections colonies per ml.) all urine cultures were sterile upon evaluation. All 17 µaue,c,c1, who underwent "'"''rPun'v -R·~·~·,., (IVP) were found to have a renal mass (table 2). these masses 9 were located in the 4 were in the lower and 4 were parapelvic. In 3 cuuu-«:,u the cyst was extremely caused sig-nificant distortion of most of the renal parenchyma and was not localized to l part of the kidney. There were 11 cysts in the left kidney and 9 cysts in the right kidney. Cysts ranged in size from l to 20 cm. in diameter. Preoperative diagnoses varied and included renal cysts in 8 patients, renal malignancy in 8, nonfunctioning kidney in 3 and pheochromocytoma in l. The variety of clinical presentations and the spectrum of radiographic findings are documented in the illustrative cases.
CASE REPORTS
Case 1. A 'White girl undervvent urologic evaluation because of recur.cent tract infections. Voiding cystourethrngraphy demonstrated right vesicoureteral refiux and an IVP showed a hypovascular left parapelvic mass (fig. 1, A). Ultrasonography of the left kidney showed a sonolucent mass consistent with a parapelvic cyst (fig. 1, B). The patient has been followed conservatively and there has been no increase in size of the renal cyst on followup ultrasonography. Case 2. A 14-year-old white boy had a large abdominal mass on physical examination and urologic consultation was obtained. Urinalysis demonstrated microscopic hematuria. An IVP showed a large left lower mass with caliceal distortion mimicking a Wihns tumor (fig. 2). Surgical exploration revealed the renal mass to be a large simple cyst and marsupialization was performed. Case 3. A 16-year-old white girl had hypertension (180/150 mm. on a routine school physical examination. Urinalysis was normal. Serum renin, urinary catecholamines, and homovanilhc and mandelic acid levels were within normal IVP showed a 5 X 6 cm. right :revealed the
Accepted for publication February 12, 1982. Read at annual meeting"ofNorth Central Section, American Urological Association, Indianapolis, Indiana, October 20-24, 1981. * Requests for reprints: Department of Urology, Mayo Clinic, 200 First St., S. W., Rochester, Minnesota 55905. 1259
TABLE
I. Types of presentation in 20 cases No. Pts.
Abdominal mass Flank pain Hypertension Enuresis Urinary tract infection Gross he1naturia Ureteropelvic junction obstruction Found during cardiac catheterization
TABLE
9
2 2 2 2 1
2. Results of IVP in 20 cases No. Pts.
Renal mass: Upper pole Lower pole Parapelvic N onfunction Laterality: Rt. Lt.
9 4
4 3 9 11
1260
KRAMER AND ASSOCIATES
FIG. 3. Case 3. IVP demonstrates large right suprarenal mass
FIG. 1. Case 1. A, IVP demonstrates hypovascular mass in left parapelvic area. B, longitudinal ultrasonogram demonstrates 3 X 4 cm. well circumscribed sonolucent parapelvic cyst. FIG. 4. Photomicrograph demonstrates fibrous cyst wall with single layer of benign, flattened epithelium without renal elements. H & E, reduced from X25.
had no increase m the size of the renal cyst on followup ultrasonography. Cytologic examination of the cyst fluid was negative for malignancy in 8 children who underwent renal cyst puncture with aspiration. Microscopy of the 16 operative specimens demonstrated a fibrous cyst wall with a single layer of flattened epithelium and no renal elements (fig. 4). DISCUSSION
FIG. 2. Case 2. IVP demonstrates large left lower pole mass with caliceal distortion mimicking Wilms tumor.
mass to be a solitary upper pole renal cyst and marsupialization was performed. Interestingly, the patient became normotensive postoperatively (150/85 mm. Hg). RESULTS
In 12 patients surgical exploration and marsupialization of the cyst wall were done. Early in our series, before the advent of modern ultrasonography, nephrectomy was done in 4 patients because the lesion was suspected of being malignant. In 4 patients the renal mass was identified by ultrasonography or computerized tomography (CT) scanning as a simple renal cyst and surgical intervention was deferred. These 4 patients, who were managed nonoperatively, remain asymptomatic and have
Simple renal cortical cysts in children have been discussed infrequently and usually have represented single case reports. Gordon and associates reported on 9 patients,2 and Bartholomew and associates added 7. 3 In all, 45 cases of simple renal cysts have been reported in the pediatric age group. In 1956 DeWeerd and Simon established the following objective criteria for the diagnosis of congenital simple cysts of the kidney in childhood: 1) the cyst is unilocular, 2) there is no communication between the cavity of the cyst and the renal pelvis, 3) the cavity of the cyst is lined with a single layer of benign epithelium and a fibrous wall containing no renal elements, 4) the cyst is solitary and the rest of the kidney has a grossly normal appearance, and 5) the renal pelvis and ureter are patent. 1 Several theories have been proposed to explain the pathogenesis of simple renal cysts in children. Gleason and associates have postulated that these are retention cysts that result from obstruction of the renal tubules due to ischemia or focal inflammation.4 Alternatively, these cysts may represent caliceal diverticula that have lost their communication with the collecting system. 2 Although an abdominal mass was the most common clinical presentation a variety of signs and symptoms prompted urologic evaluation. It is noteworthy that both of our patients with hypertension preoperatively became normotensive after ne-
1261
snvIPLE REN'AL c·ys'rS I~J CHILDfLEl"J
(from 170/110 to 120/80 n,m. and marsupialization (from 180/150 to 150/85 mm Hg). A review of the literature reveals 3 additional children who have been reported on with hypertension and renal cysts. 5 - 7 As in our patients, hypertension similarly resolved after excision of the cyst. The cause of hypertension in patients with renal cysts may be related to a localized area of ischemia with an increased production of renin. 7 Renal cysts present a spectrum of radiographic findings that may be confused with hydronephrosis, cystic Wilms tumor, mesoblastic nephroma, neuroblastoma, duplication anomalies, multicystic kidney, multilocular cystic disease, hematoma, large caliceal diverticula, renal abscess or renal cell carcinoma. 1- 4 , 8 • 9 Earlier reports advocated surgical exploration with marsupialization of the cyst wall or nephrectomy. 1 Recently, however, improved techniques in nephrotomography, ultrasonog-raphy and CT have permitted accurate delineation of the anatomic detail of these pediatric :renal masses without the necessity of invasive arteriography or surgical intervention. 3 It has been suggested that the diagnostic approach to renal masses in children be similar to that in adults and include an IVP, ultrasonography and percutaneous needle puncture, once a solid mass lesion has been excluded. 2 Ultrasonography and CT in children at our institution have been highly accurate in differentiating solid from cystic renal masses. Furthermore, our experience with percutaneous puncture and aspiration of renal cysts in young children has been encouraging. This technique can be accomplished without general anesthesia and it has been associated with few technical difficulties and no morbidity. In patients in whom optimal ultrasound evaluation is impossible because of gaseous abdominal distension CT scanning has been used with equally good results. CONCLUSIONS
Simple renal cysts in children present a spectrum of radiogrnphic findings and equivocal cases certainly require surgical intervention. However, recent advances in pediatric uroradiography and ultrasonography have caused us to recommend conservative therapy with diagnostic ultrasonography with or without renal cyst puncture in asymptomatic and normotensive
children with this disorder, As in all fields of adequate followup examination is mandatory and includes periodic physical examination, blood pressure measurements and ultrasonography. REFERENCES
L DeWeerd, J. H. and Simon, H.B.: Simple renal cysts in children: review of the literature and report of five cases. J. UroL, 75: 912, 1956. 2. Gordon, R L., Pollack, H. M., Popky, G. L. and Duckett, J. W., Jr.: Simple serous cysts of the kidney in children. Radiology, 131: 357, 1979. 3. Bartholomew, T. H., Slovis, T. L., Kroovand, R L. and Corbett, D. P.: The sonographic evaluation and management of simple renal cysts in children. J. UroL, 123: 732, 1980. 4. Gleason, D. C., McAlister, W. H. and Kissane, J.: Cystic disease of the kidneys in children. Amer. J. Roentgen., 100: 135, 1967. 5. Babka, J. C., Cohen, M. S. and Sode, J.: Solitary intrarenal cyst causing hypertension. New Engl. J. Med., 291: 343, 1974. 6. Hoard, T. D. and O'Brien, D. P., III: Simple renal cyst and high renin hypertension cured by cyst decompression. J. UroL, 115: 326, 1976. 7. Rose, H. J. and Pruitt, A. W.: Hypertension, hypeneninemia and a solitary renal cyst in an adolescent. Amer. J. Med., 61: 579, 1976.
8. Ahmed, S.: Simple renal cysts in childhood. Brit. J. UroL, 44: 71, 1972. 9. Noe, H. N. and Larimer, P. J.: Simple renal cyst manifest by proteinuria in children. J. UroL, IHI: 854, 1977.
EDITORIAL COMivrnNT This is a worthwhile article in that one does not often think of a simple cyst in children. When the evidence is unequivocal that the lesion is a cyst conservative treatment with sonographic and CT followup is an option. Yet in the case of a palpable mass the surgical urologist will find difficulty restraining himself from a permanent solution with the scalpel. Certainly in today's diagnostic setting nephrectomy does not have a place. The authors cover all these points well. Harry M. Spence Department of Urology University of Texas Southwestern Medical School Dallas, Texas
THE ,JO:JRNAL OF UT'<.Oi.OGY
Copy:'ight © 1982 by 'I'hs Vlilliam.s & Vhlkins Co.
Printed in U.S.A,
SIMPLE RENAL CYSTS IN CHILDREN STEPHEN A. KRAMER,* ALAN
n
HOFFivlAN, GAZI AYDIN
AND
PANA'i:'OTIS P. KELALIS
From the Departments of Urology and Diagnostic Radiology, Mayo Clinic and Ivlayo Foundation, Rochester, Minnesota
ABSTRACT
Simple :renal in childhood are uncommon and often are confused with duplication anomalies or renal malignancy. A review of 20 children with simple renal cysts at our institution has documented the spectrum of clinical presentations and radiog-taphic findings of this unusual renal mass. Surgical exploration and marsupialization of the cyst wall were done in 12 patients, 4 underwent nephrectomy earlier in our series and 4 have been followed conservatively by ultrasonog-raphy 01· computerized tomography scanning. Although equivocal cases necessitate surgical intervention, we advocate conservative therapy with diagnostic ultrasonography with or without puncture in asymptomatic and normotensive children with simple renal cysts. Simple benign renal cysts in childhood are rare lesions that often are confused with duplication anomalies or renal malignancy. The paucity of reported cases and the variety of radiographic findings often have caused controversy as to the most appropriate management of this renal mass. Herein we review the spectrum of clinical and radiographic presentations in 20 children with simple renal cysts of the kidney, each corresponding to radiographic or histologic criteria defined p:reviously. 1 An approach to the diagnostic evaluation and management of this uncommon renal mass is proposed. MATERIALS AND METHODS
We evaluated 11 and girls with simple renal cysts. The patients ranged in age 9 days to 19 years, with a mean age of 8 years. An abdominal mass was the most frequent clinical presentation, being found in 9 children (table 1), Other signs and symptoms included flank pain, hypertension, enuresis, tract infection, gross hematuria and n...-,c,J-c,...-nna stmction. In l child the renal cyst was m,,grmc:ea film of the kidneys at the time of evaluation of a 0~H"v"'""w. heart defect. hematuria was found at initial µ11s1,e,uca. children had a of tract infections colonies per ml.) all urine cultures were sterile upon evaluation. All 17 µaue,c,c1, who underwent "'"''rPun'v -R·~·~·,., (IVP) were found to have a renal mass (table 2). these masses 9 were located in the 4 were in the lower and 4 were parapelvic. In 3 cuuu-«:,u the cyst was extremely caused sig-nificant distortion of most of the renal parenchyma and was not localized to l part of the kidney. There were 11 cysts in the left kidney and 9 cysts in the right kidney. Cysts ranged in size from l to 20 cm. in diameter. Preoperative diagnoses varied and included renal cysts in 8 patients, renal malignancy in 8, nonfunctioning kidney in 3 and pheochromocytoma in l. The variety of clinical presentations and the spectrum of radiographic findings are documented in the illustrative cases.
CASE REPORTS
Case 1. A 'White girl undervvent urologic evaluation because of recur.cent tract infections. Voiding cystourethrngraphy demonstrated right vesicoureteral refiux and an IVP showed a hypovascular left parapelvic mass (fig. 1, A). Ultrasonography of the left kidney showed a sonolucent mass consistent with a parapelvic cyst (fig. 1, B). The patient has been followed conservatively and there has been no increase in size of the renal cyst on followup ultrasonography. Case 2. A 14-year-old white boy had a large abdominal mass on physical examination and urologic consultation was obtained. Urinalysis demonstrated microscopic hematuria. An IVP showed a large left lower mass with caliceal distortion mimicking a Wihns tumor (fig. 2). Surgical exploration revealed the renal mass to be a large simple cyst and marsupialization was performed. Case 3. A 16-year-old white girl had hypertension (180/150 mm. on a routine school physical examination. Urinalysis was normal. Serum renin, urinary catecholamines, and homovanilhc and mandelic acid levels were within normal IVP showed a 5 X 6 cm. right :revealed the
Accepted for publication February 12, 1982. Read at annual meeting"ofNorth Central Section, American Urological Association, Indianapolis, Indiana, October 20-24, 1981. * Requests for reprints: Department of Urology, Mayo Clinic, 200 First St., S. W., Rochester, Minnesota 55905. 1259
TABLE
I. Types of presentation in 20 cases No. Pts.
Abdominal mass Flank pain Hypertension Enuresis Urinary tract infection Gross he1naturia Ureteropelvic junction obstruction Found during cardiac catheterization
TABLE
9
2 2 2 2 1
2. Results of IVP in 20 cases No. Pts.
Renal mass: Upper pole Lower pole Parapelvic N onfunction Laterality: Rt. Lt.
9 4
4 3 9 11
1260
KRAMER AND ASSOCIATES
FIG. 3. Case 3. IVP demonstrates large right suprarenal mass
FIG. 1. Case 1. A, IVP demonstrates hypovascular mass in left parapelvic area. B, longitudinal ultrasonogram demonstrates 3 X 4 cm. well circumscribed sonolucent parapelvic cyst. FIG. 4. Photomicrograph demonstrates fibrous cyst wall with single layer of benign, flattened epithelium without renal elements. H & E, reduced from X25.
had no increase m the size of the renal cyst on followup ultrasonography. Cytologic examination of the cyst fluid was negative for malignancy in 8 children who underwent renal cyst puncture with aspiration. Microscopy of the 16 operative specimens demonstrated a fibrous cyst wall with a single layer of flattened epithelium and no renal elements (fig. 4). DISCUSSION
FIG. 2. Case 2. IVP demonstrates large left lower pole mass with caliceal distortion mimicking Wilms tumor.
mass to be a solitary upper pole renal cyst and marsupialization was performed. Interestingly, the patient became normotensive postoperatively (150/85 mm. Hg). RESULTS
In 12 patients surgical exploration and marsupialization of the cyst wall were done. Early in our series, before the advent of modern ultrasonography, nephrectomy was done in 4 patients because the lesion was suspected of being malignant. In 4 patients the renal mass was identified by ultrasonography or computerized tomography (CT) scanning as a simple renal cyst and surgical intervention was deferred. These 4 patients, who were managed nonoperatively, remain asymptomatic and have
Simple renal cortical cysts in children have been discussed infrequently and usually have represented single case reports. Gordon and associates reported on 9 patients,2 and Bartholomew and associates added 7. 3 In all, 45 cases of simple renal cysts have been reported in the pediatric age group. In 1956 DeWeerd and Simon established the following objective criteria for the diagnosis of congenital simple cysts of the kidney in childhood: 1) the cyst is unilocular, 2) there is no communication between the cavity of the cyst and the renal pelvis, 3) the cavity of the cyst is lined with a single layer of benign epithelium and a fibrous wall containing no renal elements, 4) the cyst is solitary and the rest of the kidney has a grossly normal appearance, and 5) the renal pelvis and ureter are patent. 1 Several theories have been proposed to explain the pathogenesis of simple renal cysts in children. Gleason and associates have postulated that these are retention cysts that result from obstruction of the renal tubules due to ischemia or focal inflammation.4 Alternatively, these cysts may represent caliceal diverticula that have lost their communication with the collecting system. 2 Although an abdominal mass was the most common clinical presentation a variety of signs and symptoms prompted urologic evaluation. It is noteworthy that both of our patients with hypertension preoperatively became normotensive after ne-
1261
snvIPLE REN'AL c·ys'rS I~J CHILDfLEl"J
(from 170/110 to 120/80 n,m. and marsupialization (from 180/150 to 150/85 mm Hg). A review of the literature reveals 3 additional children who have been reported on with hypertension and renal cysts. 5 - 7 As in our patients, hypertension similarly resolved after excision of the cyst. The cause of hypertension in patients with renal cysts may be related to a localized area of ischemia with an increased production of renin. 7 Renal cysts present a spectrum of radiographic findings that may be confused with hydronephrosis, cystic Wilms tumor, mesoblastic nephroma, neuroblastoma, duplication anomalies, multicystic kidney, multilocular cystic disease, hematoma, large caliceal diverticula, renal abscess or renal cell carcinoma. 1- 4 , 8 • 9 Earlier reports advocated surgical exploration with marsupialization of the cyst wall or nephrectomy. 1 Recently, however, improved techniques in nephrotomography, ultrasonog-raphy and CT have permitted accurate delineation of the anatomic detail of these pediatric :renal masses without the necessity of invasive arteriography or surgical intervention. 3 It has been suggested that the diagnostic approach to renal masses in children be similar to that in adults and include an IVP, ultrasonography and percutaneous needle puncture, once a solid mass lesion has been excluded. 2 Ultrasonography and CT in children at our institution have been highly accurate in differentiating solid from cystic renal masses. Furthermore, our experience with percutaneous puncture and aspiration of renal cysts in young children has been encouraging. This technique can be accomplished without general anesthesia and it has been associated with few technical difficulties and no morbidity. In patients in whom optimal ultrasound evaluation is impossible because of gaseous abdominal distension CT scanning has been used with equally good results. CONCLUSIONS
Simple renal cysts in children present a spectrum of radiogrnphic findings and equivocal cases certainly require surgical intervention. However, recent advances in pediatric uroradiography and ultrasonography have caused us to recommend conservative therapy with diagnostic ultrasonography with or without renal cyst puncture in asymptomatic and normotensive
children with this disorder, As in all fields of adequate followup examination is mandatory and includes periodic physical examination, blood pressure measurements and ultrasonography. REFERENCES
L DeWeerd, J. H. and Simon, H.B.: Simple renal cysts in children: review of the literature and report of five cases. J. UroL, 75: 912, 1956. 2. Gordon, R L., Pollack, H. M., Popky, G. L. and Duckett, J. W., Jr.: Simple serous cysts of the kidney in children. Radiology, 131: 357, 1979. 3. Bartholomew, T. H., Slovis, T. L., Kroovand, R L. and Corbett, D. P.: The sonographic evaluation and management of simple renal cysts in children. J. UroL, 123: 732, 1980. 4. Gleason, D. C., McAlister, W. H. and Kissane, J.: Cystic disease of the kidneys in children. Amer. J. Roentgen., 100: 135, 1967. 5. Babka, J. C., Cohen, M. S. and Sode, J.: Solitary intrarenal cyst causing hypertension. New Engl. J. Med., 291: 343, 1974. 6. Hoard, T. D. and O'Brien, D. P., III: Simple renal cyst and high renin hypertension cured by cyst decompression. J. UroL, 115: 326, 1976. 7. Rose, H. J. and Pruitt, A. W.: Hypertension, hypeneninemia and a solitary renal cyst in an adolescent. Amer. J. Med., 61: 579, 1976.
8. Ahmed, S.: Simple renal cysts in childhood. Brit. J. UroL, 44: 71, 1972. 9. Noe, H. N. and Larimer, P. J.: Simple renal cyst manifest by proteinuria in children. J. UroL, IHI: 854, 1977.
EDITORIAL COMivrnNT This is a worthwhile article in that one does not often think of a simple cyst in children. When the evidence is unequivocal that the lesion is a cyst conservative treatment with sonographic and CT followup is an option. Yet in the case of a palpable mass the surgical urologist will find difficulty restraining himself from a permanent solution with the scalpel. Certainly in today's diagnostic setting nephrectomy does not have a place. The authors cover all these points well. Harry M. Spence Department of Urology University of Texas Southwestern Medical School Dallas, Texas