Case Report
J Clin Ultrasound 20:466-469, September 1992 CCC 0092-2751/92/070466-04 $04.00
0 1992 by John Wiley & Sons, Inc.
Complete Regression of a Multicystic Dysplastic Kidney in the Setting of Renal Crossed Fused Ectopia Randall L. Siegel, MD, David L. Rosenfeld, MD, and Sherwin Leiman, MD
Renal crossed fused ectopia with multicystic dysplasia of a single kidney (MCDK) is an extremely rare anomaly. We believe this is the first reported case of complete regression of a multicystic dysplastic kidney in the setting of renal crossed fused ectopia. CASE REPORT
A 27-year-old woman with an obstetrical history of a single full-term uncomplicated delivery had an uneventful second pregnancy until she was approximately 32 weeks, menstrual age (MA), when she experienced vaginal bleeding. She was initially evaluated at an outside institution where an obstetrical ultrasound examination indicated a placenta previa and possible posterior urethral valves in the fetus. She was then transferred to our institution for further evaluation. An ultrasound examination performed upon admission revealed a single viable intrauterine pregnancy at 32 weeks, MA, with a complete posterior placenta previa. Examination of the fetal abdomen revealed a nonhydronephrotic right kidney measuring 4.2 cm in length, with a 3.5-cm multicystic mass contiguous with the lower pole (Figure 1). Examination of the left renal fossa revealed a normally positioned left adrenal gland with no evidence of a kidney in this area. A survey of the
From the Radiology Department, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey. For reprints contact Randall L. Siegel, MD, Radiology Department, UMDNJ-Robert Wood Johnson Medical School, One Robert Wood Johnson Place, CN 19, New Brunswick, NJ 08903. 466
fetal pelvis did not reveal a pelvic or ptotic left kidney. The fetal urinary bladder showed normal emptying and refilling during the examination. The posterior urethra was not dilated. A normal amount of amniotic fluid was recorded. A tentative diagnosis was made of an ectopic, multicystic dysplastic left kidney, with fusion to the lower pole of the right kidney. The patient’s bleeding was controlled and she was sent home on strict bed rest 18 days after admission. The patient was readmitted 5% weeks later for a cesarean section. A full-term male infant was delivered having Apgar scores of 9 at 1 minute and 9 at 5 minutes. Complete blood count and serum electrolytes were normal, including a serum creatinine of 0.6. Urinalysis done at birth was normal. The baby urinated well throughout the first day of life. A neonatal ultrasound examination revealed a normal-appearing right kidney measuring 4.6 cm in length, with a slightly prominent renal pelvis. A 4.0-cm multicystic mass was seen contiguous with and inseparable from the lower pole of the right kidney (Figure 2). The cysts ranged in size from 5 mm to 28 mm. No kidney was seen in the left renal fossa. The baby had an unremarkable hospital course and was discharged on day 5 of life. A glucoheptonate renal scan, performed at age 7 months, showed normal uptake and excretion on the right side, with no evidence of left renal activity. A repeat renal ultrasound was performed at 13 months of age. A normal right kidney was seen measuring 6.7 cm in length. The previously seen cystic mass was no longer visualized, nor was there any evidence of its previous existence (Figure 3). Again, no kidney was seen in the left renal fossa or pelvis. A t age 2
MULTICYSTIC DYSPLASTIC KIDNEY
467
FIGURE 1. Obstetrical ultrasound examination done at 32 weeks, MA. Longitudinal scan of the fetal right kidney shows a nonhydronephrotic kidney (closed arrows) with a complex cystic mass contiguous with the lower pole (open arrows).
FIGURE 2. Neonatal renal ultrasound examination. Longitudinal scan of the right kidney shows a normalappearing kidney (white arrows) with a multicystic mass contiguous and inseparable from the lower pole (black arrows).
VOL. 20, NO. 7 , SEPTEMBER 1992
CASE REPORT: SIEGEL ET AL.
468
FIGURE 3. Renal ultrasound examination done at 13 months of age. Longitudinal scan of the right kidney shows a normal-appearing kidney (between cursors) with no evidence of the previously seen multicystic mass.
the child is in good health and developing normally. DISCUSSION
Crossed renal ectopia, with or without fusion, is an unusual anomaly with a reported incidence of 1in 7500 autopsies.' It is felt to occur in the first 2 months of fetal life prior to ascension of the developing renal elements from the fetal pelvis to the fetal abdomen. It is more common on the right, with fusion of the kidneys eight times more common than nonfusion. There is a male preponderance of 3 to 2.2 In the Abeshouse and Bhisitkul series, 55% of patients with crossed fused ectopia had other pathologic conditions, most of which were other genitourinary anomalies.3 An article by Lubat et al. discusses parameters that can be used during ultrasonic evaluation of renal fusion anomalies to help make the correct d i a g n ~ s i s . ~ Multicystic dyplasia in a crossed ectopia is a rare ~ i t u a t i o n .In ~ the Abeshous series, it occurred in 7 of their 443 patients (1.6%) with
crossed e ~ t o p i a One . ~ theory to explain this occurrence considers obstruction to the ectopic ureter by either the renal fusion or the anomalous blood s u ~ p l y Kleiner .~ et al. reported contralatera1 renal anomalies in 41% of patients with MCDK, ranging from mild renal pyelectasis to contralateral MCDK and renal aplasia.6 Gruenwald et al. suggested prognostic groups based on careful ultrasonic examination of the fetal genitourinary system when multiple anomalies are pre~ent.~ Ultrasound criteria of MCDK are well known, including randomly distributed, noncommunicating cysts varying in size, a lobular renal contour with no peripheral parenchyma, and absent central sinus complex.5y8In the series of MCDK in crossed fused ectopia reported by Nussbaum et al., moderate hydronephrosis in the orthotopic kidney was observed in 3 of 4 cases.5 In our case this finding was not present. In the past few years, the natural progression of MCDK has been elucidated via serial ultrasound follow-up In the series of Vinocur et al., the authors reported no change in JOURNAL OF CLINICAL ULTRASOUND
MULTICYSTIC DYSPLASTIC KIDNEY
size in 73%, a decrease in size or disappearance in 13.5%, and an increase in size in 13.5%.11 There are reports of MCDK that regressed completely in serial ultrasound examinations and later were surgically explored revealing no evidence of the kidney, renal artery, or ureter.’-’’ One must speculate that a certain percentage of patients diagnosed with renal agenesis actually had MCDK that completely regre~sed.~ Avni et al. speculated that some MCDKs regress because cysts increase for a time, owing to some functioning glomeruli, followed by fluid resorption and fibrosis after cessation of residual renal function.’ Another theory suggests the possibility of leakage of fluid from the cysts because of iatrogenic or blunt abdominal trauma.” The timing of regression varies, from complete regression by birth to decreasing size over years.” The management of MCDK is currently in a state of flux. Prior to the insight afforded by ultrasonography, nephrectomy was considered the method of choice for diagnosis as well as therapy. With careful ultrasound examination supplemented by nuclear scintigraphy or antegrade pyelography, the diagnosis of MCDK can usually be made with certainty.” Many authors now believe that a reasonable way to follow these patients is with both clinical observation and ultrasound evaluation. The 4 possible complications of nonsurgically treated MCDK disease most often cited include hypertension, malignant transformation, infection, and problems related to sheer It is generally felt that the incidence of these If such lecomplications is very sma11.10~11~13~’4 sions are left in place, careful clinical monitoring for the development of complications is necessary on a regular basis.1°-12 In summary, ultrasonography has enabled the radiologist t o diagnose many complex renal anomalies. One should always keep in mind the more unusual situations so that the correct radiologic diagnosis will be made, ensuring proper clinical management.
VOL. 20, NO. 7, SEPTEMBER 1992
469
REFERENCES 1. Goodman JD, Norton KI, Carr L, et al: Crossed fused renal ectopia: Sonographic diagnosis. Urol Radiol 8:13, 1986. 2. Rosenberg HK, Snyder HM, Duckett J: Abdominal mass in a newborn: Multicystic dysplasia of crossed fused ectopia: Ultrasonic demonstration. J . Urol 131:1160-1161, 1984. 3. Abeshouse BS, Bhisitkul I: Crossed renal ectopia with and without fusion. Urol Int 9:63, 1959. 4. Lubat E, Hernanz-Schulman M, Genieser NB, Ambrosino MM, Teele RL: Sonography of the simple and complicated ipsilateral fused kidney. J Ultrasound Med 8:109, 1989. 5. Nussbaum AR, Hartman DS, Whitely N, McCauley RGK, Sanders RC: Multicystic dysplasia and crossed renal ectopia. A J R 149:407-410, 1987. 6. Kleiner B, Filly RA, Mack L, Callen PW: Multicystic dysplastic kidney: Observations of contralateral disease in the fetal population. Radiol 161:27-29, 1986. 7. Greunewald SM, Crocker EF, Walker AG, Trudinger BJ: Antenatal diagnosis of urinary tract abnormalities: Correlation of ultrasound appearance with postnatal diagnosis. A m J Obstet Gynecol 148:278- 283, 1984. 8. Sanders RC, Hartman DS: The sonographic distinction between neonatal multicystic kidney and hydronephrosis. Radiology 105621- 625, 1985. 9. Avni EF, Thoua Y, Lalmand B, Didier F, Droulle P, Schulman CC: Multicystic dysplastic kidney: Natural history from in utero diagnosis and postnatal followup. J Urol 138:1420- 1424, 1987. 10. Pedicelli G, Jequier S, Bowen A, Boisvert J: Multicystic dysplastic kidneys: Spontaneous regression demonstrated with ultrasound. Radiology 160~23-26,1986. 11. Vinocur L, Slovis TL, Perlmutter AD, Watts FB, Chang C: Follow-up studies of multicystic dysplastic kidneys. Radiology 167:311-315, 1988. 12. Hartman GE, Shochat SJ, In reply to letter. AJDC 141:603, 1987. 13. Bowen A: Multicystic dysplastic kidneys- Letter to the Editor. AJDC 141:602-603, 1987. 14. Stanisic TH: Review of “The dilemma of the multicystic dysplastic kidney.” Am J Dis Children 140:865, 1986.
J Clin Ultrasound 20:466-469, September 1992 CCC 0092-2751/92/070466-04 $04.00
0 1992 by John Wiley & Sons, Inc.
Complete Regression of a Multicystic Dysplastic Kidney in the Setting of Renal Crossed Fused Ectopia Randall L. Siegel, MD, David L. Rosenfeld, MD, and Sherwin Leiman, MD
Renal crossed fused ectopia with multicystic dysplasia of a single kidney (MCDK) is an extremely rare anomaly. We believe this is the first reported case of complete regression of a multicystic dysplastic kidney in the setting of renal crossed fused ectopia. CASE REPORT
A 27-year-old woman with an obstetrical history of a single full-term uncomplicated delivery had an uneventful second pregnancy until she was approximately 32 weeks, menstrual age (MA), when she experienced vaginal bleeding. She was initially evaluated at an outside institution where an obstetrical ultrasound examination indicated a placenta previa and possible posterior urethral valves in the fetus. She was then transferred to our institution for further evaluation. An ultrasound examination performed upon admission revealed a single viable intrauterine pregnancy at 32 weeks, MA, with a complete posterior placenta previa. Examination of the fetal abdomen revealed a nonhydronephrotic right kidney measuring 4.2 cm in length, with a 3.5-cm multicystic mass contiguous with the lower pole (Figure 1). Examination of the left renal fossa revealed a normally positioned left adrenal gland with no evidence of a kidney in this area. A survey of the
From the Radiology Department, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey. For reprints contact Randall L. Siegel, MD, Radiology Department, UMDNJ-Robert Wood Johnson Medical School, One Robert Wood Johnson Place, CN 19, New Brunswick, NJ 08903. 466
fetal pelvis did not reveal a pelvic or ptotic left kidney. The fetal urinary bladder showed normal emptying and refilling during the examination. The posterior urethra was not dilated. A normal amount of amniotic fluid was recorded. A tentative diagnosis was made of an ectopic, multicystic dysplastic left kidney, with fusion to the lower pole of the right kidney. The patient’s bleeding was controlled and she was sent home on strict bed rest 18 days after admission. The patient was readmitted 5% weeks later for a cesarean section. A full-term male infant was delivered having Apgar scores of 9 at 1 minute and 9 at 5 minutes. Complete blood count and serum electrolytes were normal, including a serum creatinine of 0.6. Urinalysis done at birth was normal. The baby urinated well throughout the first day of life. A neonatal ultrasound examination revealed a normal-appearing right kidney measuring 4.6 cm in length, with a slightly prominent renal pelvis. A 4.0-cm multicystic mass was seen contiguous with and inseparable from the lower pole of the right kidney (Figure 2). The cysts ranged in size from 5 mm to 28 mm. No kidney was seen in the left renal fossa. The baby had an unremarkable hospital course and was discharged on day 5 of life. A glucoheptonate renal scan, performed at age 7 months, showed normal uptake and excretion on the right side, with no evidence of left renal activity. A repeat renal ultrasound was performed at 13 months of age. A normal right kidney was seen measuring 6.7 cm in length. The previously seen cystic mass was no longer visualized, nor was there any evidence of its previous existence (Figure 3). Again, no kidney was seen in the left renal fossa or pelvis. A t age 2
MULTICYSTIC DYSPLASTIC KIDNEY
467
FIGURE 1. Obstetrical ultrasound examination done at 32 weeks, MA. Longitudinal scan of the fetal right kidney shows a nonhydronephrotic kidney (closed arrows) with a complex cystic mass contiguous with the lower pole (open arrows).
FIGURE 2. Neonatal renal ultrasound examination. Longitudinal scan of the right kidney shows a normalappearing kidney (white arrows) with a multicystic mass contiguous and inseparable from the lower pole (black arrows).
VOL. 20, NO. 7 , SEPTEMBER 1992
CASE REPORT: SIEGEL ET AL.
468
FIGURE 3. Renal ultrasound examination done at 13 months of age. Longitudinal scan of the right kidney shows a normal-appearing kidney (between cursors) with no evidence of the previously seen multicystic mass.
the child is in good health and developing normally. DISCUSSION
Crossed renal ectopia, with or without fusion, is an unusual anomaly with a reported incidence of 1in 7500 autopsies.' It is felt to occur in the first 2 months of fetal life prior to ascension of the developing renal elements from the fetal pelvis to the fetal abdomen. It is more common on the right, with fusion of the kidneys eight times more common than nonfusion. There is a male preponderance of 3 to 2.2 In the Abeshouse and Bhisitkul series, 55% of patients with crossed fused ectopia had other pathologic conditions, most of which were other genitourinary anomalies.3 An article by Lubat et al. discusses parameters that can be used during ultrasonic evaluation of renal fusion anomalies to help make the correct d i a g n ~ s i s . ~ Multicystic dyplasia in a crossed ectopia is a rare ~ i t u a t i o n .In ~ the Abeshous series, it occurred in 7 of their 443 patients (1.6%) with
crossed e ~ t o p i a One . ~ theory to explain this occurrence considers obstruction to the ectopic ureter by either the renal fusion or the anomalous blood s u ~ p l y Kleiner .~ et al. reported contralatera1 renal anomalies in 41% of patients with MCDK, ranging from mild renal pyelectasis to contralateral MCDK and renal aplasia.6 Gruenwald et al. suggested prognostic groups based on careful ultrasonic examination of the fetal genitourinary system when multiple anomalies are pre~ent.~ Ultrasound criteria of MCDK are well known, including randomly distributed, noncommunicating cysts varying in size, a lobular renal contour with no peripheral parenchyma, and absent central sinus complex.5y8In the series of MCDK in crossed fused ectopia reported by Nussbaum et al., moderate hydronephrosis in the orthotopic kidney was observed in 3 of 4 cases.5 In our case this finding was not present. In the past few years, the natural progression of MCDK has been elucidated via serial ultrasound follow-up In the series of Vinocur et al., the authors reported no change in JOURNAL OF CLINICAL ULTRASOUND
MULTICYSTIC DYSPLASTIC KIDNEY
size in 73%, a decrease in size or disappearance in 13.5%, and an increase in size in 13.5%.11 There are reports of MCDK that regressed completely in serial ultrasound examinations and later were surgically explored revealing no evidence of the kidney, renal artery, or ureter.’-’’ One must speculate that a certain percentage of patients diagnosed with renal agenesis actually had MCDK that completely regre~sed.~ Avni et al. speculated that some MCDKs regress because cysts increase for a time, owing to some functioning glomeruli, followed by fluid resorption and fibrosis after cessation of residual renal function.’ Another theory suggests the possibility of leakage of fluid from the cysts because of iatrogenic or blunt abdominal trauma.” The timing of regression varies, from complete regression by birth to decreasing size over years.” The management of MCDK is currently in a state of flux. Prior to the insight afforded by ultrasonography, nephrectomy was considered the method of choice for diagnosis as well as therapy. With careful ultrasound examination supplemented by nuclear scintigraphy or antegrade pyelography, the diagnosis of MCDK can usually be made with certainty.” Many authors now believe that a reasonable way to follow these patients is with both clinical observation and ultrasound evaluation. The 4 possible complications of nonsurgically treated MCDK disease most often cited include hypertension, malignant transformation, infection, and problems related to sheer It is generally felt that the incidence of these If such lecomplications is very sma11.10~11~13~’4 sions are left in place, careful clinical monitoring for the development of complications is necessary on a regular basis.1°-12 In summary, ultrasonography has enabled the radiologist t o diagnose many complex renal anomalies. One should always keep in mind the more unusual situations so that the correct radiologic diagnosis will be made, ensuring proper clinical management.
VOL. 20, NO. 7, SEPTEMBER 1992
469
REFERENCES 1. Goodman JD, Norton KI, Carr L, et al: Crossed fused renal ectopia: Sonographic diagnosis. Urol Radiol 8:13, 1986. 2. Rosenberg HK, Snyder HM, Duckett J: Abdominal mass in a newborn: Multicystic dysplasia of crossed fused ectopia: Ultrasonic demonstration. J . Urol 131:1160-1161, 1984. 3. Abeshouse BS, Bhisitkul I: Crossed renal ectopia with and without fusion. Urol Int 9:63, 1959. 4. Lubat E, Hernanz-Schulman M, Genieser NB, Ambrosino MM, Teele RL: Sonography of the simple and complicated ipsilateral fused kidney. J Ultrasound Med 8:109, 1989. 5. Nussbaum AR, Hartman DS, Whitely N, McCauley RGK, Sanders RC: Multicystic dysplasia and crossed renal ectopia. A J R 149:407-410, 1987. 6. Kleiner B, Filly RA, Mack L, Callen PW: Multicystic dysplastic kidney: Observations of contralateral disease in the fetal population. Radiol 161:27-29, 1986. 7. Greunewald SM, Crocker EF, Walker AG, Trudinger BJ: Antenatal diagnosis of urinary tract abnormalities: Correlation of ultrasound appearance with postnatal diagnosis. A m J Obstet Gynecol 148:278- 283, 1984. 8. Sanders RC, Hartman DS: The sonographic distinction between neonatal multicystic kidney and hydronephrosis. Radiology 105621- 625, 1985. 9. Avni EF, Thoua Y, Lalmand B, Didier F, Droulle P, Schulman CC: Multicystic dysplastic kidney: Natural history from in utero diagnosis and postnatal followup. J Urol 138:1420- 1424, 1987. 10. Pedicelli G, Jequier S, Bowen A, Boisvert J: Multicystic dysplastic kidneys: Spontaneous regression demonstrated with ultrasound. Radiology 160~23-26,1986. 11. Vinocur L, Slovis TL, Perlmutter AD, Watts FB, Chang C: Follow-up studies of multicystic dysplastic kidneys. Radiology 167:311-315, 1988. 12. Hartman GE, Shochat SJ, In reply to letter. AJDC 141:603, 1987. 13. Bowen A: Multicystic dysplastic kidneys- Letter to the Editor. AJDC 141:602-603, 1987. 14. Stanisic TH: Review of “The dilemma of the multicystic dysplastic kidney.” Am J Dis Children 140:865, 1986.
