eMedicine Specialties > Radiology > Pediatrics

Multilocular Cystic Nephroma

Henrique M Lederman, MD, PhD, Consulting Staff, Department of Radiology, LeBonheur Children's Medical Center and St Jude Children's Research Hospital; Professor of Radiology and Pediatric Radiology, Chief, Division of Diagnostic Imaging in Pediatrics, Federal University of Sao Paulo, Brazil
Peter J Hurh, Research Fellow, Department of Radiology, The Children's Hospital of Philadelphia

Updated: Apr 7, 2009

Introduction

Background

In the past, multilocular cystic renal tumors have been considered to be lesions of developmental origin, hamartomas, or hamartomas with malignant potential. In 1956, Boggs and Kimmelstiel first proposed the true neoplastic nature of the lesions in a case report, suggesting the term benign multilocular cystic nephroma for this condition.^1,2,3

Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several hypoattenuating cysts. No enhancement or septation is noted.

Multilocular cystic nephroma. Axial MRI shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Pathophysiology

Multilocular cystic renal tumor is characterized as a solitary, well-circumscribed, multiseptated mass of noncommunicating fluid-filled loculi that is surrounded by a thick fibrous capsule and compressed renal parenchyma. The mass is typically large. Madewell et al discovered that the mean size of the mass is 7.6 X 9.7 cm. Kettritz et al reported solitary tumors sized 3.3-13 cm, with an average maximum diameter of 6.7 cm.^5,6

The most commonly reported location for this tumor originates at the lower pole, although tumors have been known to originate in other areas. Kettritz et al discovered tumors that originated in the middle third of the kidney in 5 patients, in the upper pole of the kidney in 1 patient, and in the lower pole of the kidney in 1 patient.⁶ All 7 lesions were multiseptated cysts, arising in the right kidney in 3 patients and in the left kidney in 4 patients.

The contents of the cyst consist of either clear-to-yellow fluid (similar to serum) or thick myxomatous gel. Although complications are unusual, cyst herniation into the renal pelvis has been described as occurring most frequently. On gross inspection, solid nodules of tissue are not discernible, and hemorrhage and necrosis is usually not found. Calcification is also uncommon.

Frequency

United States

Multilocular cystic renal tumors are rare; therefore, determining the true prevalence and the age and sex distributions is difficult.

Mortality/Morbidity

No mortality is associated with this disease. Morbidity is related to the single functional kidney.

Race

Multilocular cystic nephroma has no racial predilection.

Sex

Multilocular cystic renal tumors have been noted to affect males, predominantly in childhood, and females, predominantly in adulthood.

Age

Castillo et al found that two thirds of the tumors occurred in children aged 3 months to 2 years, with a male-to-female predominance ratio of 2:1.⁷ Of tumors in this group, almost 50% contained blastema; therefore, they were classified as cystic partially differentiated nephroblastomas (CPDNs).

Of patients aged 30 years or older (approximately 30% of patients), an 8:1 female-to-male predominance was found. Of this group, fewer than 20% of tumors were CPDNs. Other groups have reported similar results. Madewell et al found that, in childhood, 73% of cases occurred in boys younger than 4 years. In patients older than 4 years, 89% of cases occurred in females, who presented with findings of an abdominal mass.⁵

Anatomy

Anatomically, cystic nephroma and cystic partially differentiated nephroblastomas (CPDNs) are identical; however, they are histologically distinct. In cystic nephroma, as defined by Joshi and Beckwith,⁴ the septa consist of fibrous tissue that may contain well-differentiated renal tubules but no poorly differentiated tissues or blastemal cells. CPDN has the histologic features of cystic nephroma with the addition of septal blastemal cells in any amount, with or without other embryonal stroma or epithelial cell types.

CPDN can be further classified as grade 1 or 2 tumors. In grade 1 CPDN, the relatively mature subtype, the septa contain more than 50% mature elements. Grade 2 CPDNs contain less than 50% mature septal elements.

A CPDN must also be pathologically distinguished from a Wilms tumor (its primary differential diagnosis), in which cysts have formed as a consequence of hemorrhage and necrosis in solid tissue.

Presentation

Multilocular cystic renal tumors are usually detected in children when a caretaker or physician incidentally discovers a painless abdominal mass. In adults, signs and symptoms are nonspecific; the most common include pain, hematuria, and urinary tract infections. No serologic marker for the lesions has been found.

In CPDN, when blastema is present in the septa of a multilocular cystic renal tumor, the potential for more aggressive behavior is implied despite the usually benign course of the tumor. In patients with these findings, surgery is required for diagnosis, because neither clinical examination nor radiologic evaluation is useful in predicting the histologic characteristics. If the tumor proves to be a cystic partially differentiated nephroblastoma (CPDN), regular noninvasive monitoring is advocated.

The demonstration of septa is necessary to distinguish multilocular cystic renal tumors from simple cysts. The demonstration of thin septa and the lack of enhancing nodules within the tumor must be seen to help establish the preoperative diagnosis of the tumor, which may be important to direct more conservative surgical therapy.

Preferred Examination

Ultrasonography (US) is the first radiologic examination performed for the evaluation of any abdominal mass. US can provide the imaging results necessary for diagnosing multilocular cystic nephroma. The diagnosis may be confirmed by using either CT or MRI. Together, US and CT may be the studies of choice because they enable the evaluation of cystic lesions, stromal tissue, and the perfusion of this stroma. No flow is seen within the cystic lesions.

Limitations of Techniques

• The precision and accuracy of US depends on, and therefore is limited by, the operator's skill.
• CT may not be chosen if the patient has a severe allergy to the contrast medium.
• Compared with US and fast CT, MRI is limited by the need for sedation in some patients.

Differential Diagnoses

Wilms Tumor

Other Problems to Be Considered

Polycystic kidney disease
Hydronephrosis

Clear cell sarcoma may contain multiple cystic spaces secondary to hemorrhage and necrosis. These lesions may mimic multilocular cystic renal tumors. Histologically, a clear cell sarcoma is distinct from a Wilms tumor, it has a proclivity to metastasize to bone, and it has a poor prognosis.

Radiography

Findings

On plain radiographs, cystic nephroma and cystic partially differentiated nephroblastoma (CPDN) cannot be distinguished, just as they cannot be distinguished by their gross anatomic appearances. However, in either type of multilocular cystic renal tumor, radiography does reveal displacement of the bowel and adjacent structures if the lesion is of sufficient size. Calcification, although uncommon, can be present and is defined as curvilinear and peripheral localizations.⁸

On excretory urography, the kidneys function normally with multilocular cystic renal tumors. Because the mass is rarely suspected on the basis of the clinical findings, excretory urography reveals nonspecific stretching, displacement, extension of the tumor to the renal pelvis, and attenuation of the renal collecting system by the mass. Delayed or absent excretion is also demonstrated.

Degree of Confidence

A general nonspecific renal tumor can be identified by using radiography, with some degree of confidence. However, the use of radiography to diagnose multilocular cystic nephroma specifically results in a low degree of confidence. On plain radiographs, multilocular cystic renal tumor appears similar to other renal tumors because plain radiography cannot be used to differentiate between cystic and solid lesions.

False Positives/Negatives

The occurrence of false-positive and false-negative results is high because plain radiography cannot be used to differentiate between specific structures, and the study has low precision in the diagnosis of these tumors.

Computed Tomography

Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several hypoattenuating cysts. No enhancement or septation is noted.

Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several cysts with hypoattenuation. No enhancement or septation is noted. Perfusion can be seen crossing the midline on part of the remaining left kidney.

Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several cysts with hypoattenuation. No enhancement or septation is noted. Perfusion is seen crossing the midline on part of the remaining left kidney, with some signs of dilatation of the collecting system.

Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several cysts with hypoattenuation. No enhancement or septation is noted. Perfusion is seen crossing the midline on part of the remaining left kidney, with some signs of dilatation of the collecting system.

Multilocular cystic nephroma. CT shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Multilocular cystic nephroma. CT shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Findings

CT findings are dependent on the size of the cyst and the amount of stromal tissue. In most cases, the mass is identified with the following CT findings⁹ :

• Well-defined margins
• Multicystic architecture
• Enhancing septa
• Herniation into the renal collecting system

Cystic spaces are not enhancing and demonstrate CT numbers slightly higher than those of water. In some cases, the entire mass or portions of the mass may appear solid because of smaller closely spaced cysts.

Degree of Confidence

CT results in a high degree of confidence in the diagnosis of multilocular cystic nephroma. CT images define the structures of lesions on the kidneys well.

False Positives/Negatives

False-positive and false-negative rates are low because of the accuracy of the method.

Magnetic Resonance Imaging

Multilocular cystic nephroma. Axial MRI shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Multilocular cystic nephroma. Axial MRI shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Multilocular cystic nephroma. Sagittal MRI shows a large multilocular cystic nephroma involving the right kidney.

Findings

• MRI demonstrates the low signal intensity of the tumor capsule.
• Observations of nonenhanced MRIs have shown encapsulated masses with dividing septa between cystic spaces.
• Kettritz et al⁶ found the following:
  • On T1-weighted sequences, signal intensity varies from low to very high and from low to intermediate.
  • T2-weighted sequencing resulted in low signal intensity in the tumor capsule and the intermediate septations.
  • The signal intensity of the cysts was high in all cases.
  • Variable signal intensity from the cyst contents is attributed to differing concentrations of old hemorrhage and protein.

Degree of Confidence

MRI results in a high degree of confidence in the diagnosis of multilocular cystic nephroma. MRI images define the structures of lesions on the kidneys well.

False Positives/Negatives

False-positive and false-negative rates are low because of the accuracy of the method.

Ultrasonography

Multilocular cystic nephroma. Sonograms show a normal right kidney and, within an enlarged left kidney, multiple anechoic cystic changes separated by hyperechoic septa.

Multilocular cystic nephroma. Sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney.

Multilocular cystic nephroma. Sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney.

Multilocular cystic nephroma. Color Doppler sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney without Doppler flow.

Multilocular cystic nephroma. Color Doppler sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney without Doppler flow.

Findings

Results of US depend on the amount of stroma and the size of the loculi.¹⁰

• The appearance of multilocular cystic renal tumor includes multiple anechoic spaces separated by hyperechoic septa. This pattern is similar to that of multilocular cystic nephroma; however, if the loculi are small, the tumor mimics an echogenic solid mass.
• In most patients, the renal origin of the mass can be confirmed by identifying a beak or claw of normal renal parenchyma around the periphery of a well-defined mass, by the splaying or displacement of the renal collecting system, and by synchronous motion of the mass and kidney with respiratory excursion.
• Color Doppler US can also be used to evaluate tumors and can provide a noninvasive assessment of lesion vascularity. This is possible because of the Doppler-shifted signals of abnormally high velocity emitted by low-resistance neovascularity in some neoplasms.

Degree of Confidence

US can be used with a high degree of confidence. A diagnosis can be made with high precision because sonograms clearly depict the structure of the lesions.

False Positives/Negatives

False-positive and false-negative rates are low because of the accuracy of the method.

Nuclear Imaging

Findings

Scintigraphy of the kidneys can be performed. Scintigrams demonstrate a defect corresponding to the renal mass.

Degree of Confidence

Nuclear medicine studies result in a low degree of confidence in the diagnosis of multilocular cystic nephroma specifically. Although a general nonspecific renal mass can be identified, details cannot be differentiated.

False Positives/Negatives

The lack of precision results in high false-positive and false-negative rates because of the inaccuracy of the method.

Angiography

Findings

On angiographic examination, multilocular cystic renal tumors usually appear hypovascular, although they may also be avascular or hypervascular. Angiography may reveal features that are not specific for differential diagnosis. Magnetic resonance angiography may help if a preoperative evaluation of the vascular anatomy is needed.

Degree of Confidence

Angiography results in a high degree of confidence. The structures of lesions on the kidneys are well differentiated with this method, which results in a precise diagnosis.

False Positives/Negatives

Angiography has low false-positive and false-negative rates because of the accuracy of the method.

Multimedia

Media file 1: Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several hypoattenuating cysts. No enhancement or septation is noted.

Media file 2: Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several cysts with hypoattenuation. No enhancement or septation is noted. Perfusion can be seen crossing the midline on part of the remaining left kidney.

Media file 3: Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several cysts with hypoattenuation. No enhancement or septation is noted. Perfusion is seen crossing the midline on part of the remaining left kidney, with some signs of dilatation of the collecting system.

Media file 4: Multilocular cystic nephroma. CT shows a normal right kidney and an enlarged left kidney with a large well-defined mass, with several cysts with hypoattenuation. No enhancement or septation is noted. Perfusion is seen crossing the midline on part of the remaining left kidney, with some signs of dilatation of the collecting system.

Media file 5: Multilocular cystic nephroma. CT shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Media file 6: Multilocular cystic nephroma. CT shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Media file 7: Multilocular cystic nephroma. Sonograms show a normal right kidney and, within an enlarged left kidney, multiple anechoic cystic changes separated by hyperechoic septa.

Media file 8: Multilocular cystic nephroma. Sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney.

Media file 9: Multilocular cystic nephroma. Sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney.

Media file 10: Multilocular cystic nephroma. Color Doppler sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney without Doppler flow.

Media file 11: Multilocular cystic nephroma. Color Doppler sonogram shows multiple anechoic cystic changes separated by hyperechoic septa within an enlarged left kidney without Doppler flow.

Media file 12: Multilocular cystic nephroma. Axial MRI shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Media file 13: Multilocular cystic nephroma. Axial MRI shows a large multilocular cystic nephroma involving the right kidney and crossing the midline.

Media file 14: Multilocular cystic nephroma. Sagittal MRI shows a large multilocular cystic nephroma involving the right kidney.

References

1. Boggs LK, Kimmelstiel P. Benign multilocular cystic nephroma: report of two cases of so-called multilocular cyst of the kidney. J Urol. 1956;76:530-41.

2. Stamatiou K, Polizois K, Kollaitis G, Dahanis S, Zafeiropoulos G, Leventis C, et al. Cystic nephroma: a case report and review of the literature. Cases J. Oct 23 2008;1(1):267. [Medline].

3. Silver IM, Boag AH, Soboleski DA. Best cases from the AFIP: Multilocular cystic renal tumor: cystic nephroma. Radiographics. Jul-Aug 2008;28(4):1221-5; discussion 1225-6. [Medline].

4. Joshi VV, Beckwith JB. Multilocular cyst of the kidney (cystic nephroma) and cystic, partially differentiated nephroblastoma. Terminology and criteria for diagnosis. Cancer. Jul 15 1989;64(2):466-79. [Medline].

5. Madewell JE, Goldman SM, Davis CJ Jr, et al. Multilocular cystic nephroma: a radiographic-pathologic correlation of 58 patients. Radiology. Feb 1983;146(2):309-21. [Medline].

6. Kettritz U, Semelka RC, Siegelman ES, et al. Multilocular cystic nephroma: MR imaging appearance with current techniques, including gadolinium enhancement. J Magn Reson Imaging. Jan-Feb 1996;6(1):145-8. [Medline].

7. Castillo OA, Boyle ET Jr, Kramer SA. Multilocular cysts of kidney. A study of 29 patients and review of literature. Urology. Feb 1991;37(2):156-62. [Medline].

8. La Parra Casado C, Muro Velilla D, Molina Fàbrega R, Sangüesa Nebot C. [Radiologic findings in non-Wilms' renal tumors in children]. Radiologia. May-Jun 2008;50(3):215-24. [Medline].

9. Han XN, Peng LR, Liu GH, Wang J. [Multiphasic spiral CT scanning features in 100 patients with small renal cell carcinoma]. Zhonghua Zhong Liu Za Zhi. May 2007;29(5):382-5. [Medline].

10. Deeg KH, Gerdemann C, Weingärtner K, Seitz G. Sonographic diagnosis of an unusual case of multilocular cystic nephroma mimicking polycystic kidney disease. Ultraschall Med. Dec 2008;29 Suppl 5:264-7. [Medline].

11. Abt AB, Demers LM, Shochat SJ. Cystic nephroma: an ultrastructural and biochemical study. J Urol. Oct 1979;122(4):539-41. [Medline].

12. Agrons GA, Wagner BJ, Davidson AJ, Suarez ES. Multilocular cystic renal tumor in children: radiologic-pathologic correlation. Radiographics. May 1995;15(3):653-69. [Medline].

13. Banner MP, Pollack HM, Chatten J, Witzleben C. Multilocular renal cysts: radiologic-pathologic correlation. AJR Am J Roentgenol. Feb 1981;136(2):239-47. [Medline].

14. Brown JM. Cystic partially differentiated nephroblastoma. J Pathol. Mar 1975;115(3):175-8. [Medline].

15. Carlson DH, Carlson D, Simon H. Benign multilocal cystic nephroma. AJR Am J Roentgenol. Oct 1978;131(4):621-5. [Medline].

16. Christ ML. Polycystic nephroblastoma. J Urol. Nov 1967;98(5):570-5. [Medline].

17. Dalla-Palma L, Pozzi-Mucelli F, di Donna A, Pozzi-Mucelli RS. Cystic renal tumors: US and CT findings. Urol Radiol. 1990;12(2):67-73. [Medline].

18. Davidson AJ, Hartman DS, eds. Radiology of the Kidney and Urinary Tract. 2nd ed. Philadelphia: WB Saunders Co;1994.

19. Dikengil A, Benson M, Sanders L, Newhouse JH. MRI of multilocular cystic nephroma. Urol Radiol. 1988;10(2):95-9. [Medline].

20. Edmonds W. Cystic adenoma of the kidney. Trans Pathol Soc London. 1892;43:89-90.

21. Fowler M. Differentiated nephroblastoma: solid, cystic or mixed. J Pathol. Nov 1971;105(3):215-8. [Medline].

22. Gervais DA, Whitman GJ, Chew FS. Multilocular cyst of the kidney. AJR Am J Roentgenol. Sep 1993;161(3):600. [Medline].

23. Landing BH. Well-differentiated and polycystic (benign?) Wilms' tumor. Cancer Semin. 1968;2:110-3.

24. Lazner J, Jureidini KF. Benign cystic differentiated nephroblastoma in an infant. S Austral Clin. 1971;5:279-83.

25. Polat P, Suma S, Celenk C, et al. Quiz case of the month. Multilocular cystic nephroma (MLCN). Eur Radiol. 1997;7(5):757-8. [Medline].

26. Simonton SC, Dehner LP. In: Stocker JT, Dehner LP, eds. Pediatric Pathology. Philadelphia: Lippincott;1992:825-71.

27. Uson AC, Melicow MM. Multilocular cysts of kidney with intrapelvic herniation of a "daughter" cyst: report of 4 cases. J Urol. 1963;3:341-8.

Keywords

multilocular cystic nephroma, multilocular cystic renal tumor, cystic nephroma, cystic partially differentiated nephroblastoma, CPDN, multilocular cystic renal tumor, benign multilocular cystic nephroma, polycystic nephroblastoma, differentiated nephroblastoma, well-differentiated polycystic Wilms tumor, benign cystic differentiated nephroblastoma, cystic partially differentiated nephroblastoma

Contributor Information and Disclosures

Author

Henrique M Lederman, MD, PhD, Consulting Staff, Department of Radiology, LeBonheur Children's Medical Center and St Jude Children's Research Hospital; Professor of Radiology and Pediatric Radiology, Chief, Division of Diagnostic Imaging in Pediatrics, Federal University of Sao Paulo, Brazil
Henrique M Lederman, MD, PhD is a member of the following medical societies: Society for Pediatric Radiology
Disclosure: Nothing to disclose.

Coauthor(s)

Peter J Hurh, Research Fellow, Department of Radiology, The Children's Hospital of Philadelphia
Disclosure: Nothing to disclose.

Medical Editor

Lori Lee Barr, MD, FACR, FAIUM, Clinical Associate Professor of Radiology, University of Texas Health Science Center in San Antonio; Clinical Assistant Professor of Radiology, University of Texas Medical Branch at Galveston; Member, Board of Directors, Austin Radiological Association; Consulting Staff, Seton Health Network, Columbia/St David's Healthcare System, Healthsouth Rehabilitation Hospital of Austin, Georgetown Hospital, St Mark's Medical Center, Cedar Park Regional Medical Center
Lori Lee Barr, MD, FACR, FAIUM is a member of the following medical societies: American Association for Women Radiologists, American College of Radiology, American Institute of Ultrasound in Medicine, American Roentgen Ray Society, American Society of Pediatric Neuroradiology, Association of University Radiologists, Radiological Society of North America, Society for Pediatric Radiology, Society of Radiologists in Ultrasound, Southern Medical Association, Texas Radiological Society, and Undersea and Hyperbaric Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

Lawrence M Davis, MD, Assistant Professor of Diagnostic Imaging (Clinical), Department of Diagnostic Imaging, Warren Alpert Medical School at Brown University
Lawrence M Davis, MD is a member of the following medical societies: American College of Radiology, American Roentgen Ray Society, American Society of Neuroradiology, Radiological Society of North America, and Rhode Island Medical Society
Disclosure: Nothing to disclose.

Related eMedicine topics

Mesoblastic Nephroma

Oncocytoma, Kidney

Angiomyolipoma, Kidney

Kidney Transplantation

Acquired Cystic Kidney Disease

Guidelines

Diagnosis and Management of Chronic Kidney Disease

ACR Appropriateness Criteria® indeterminate renal masses. American College of Radiology.  1996 (revised 2007).  7 pages.  NGC:005996

 
Clinical trials

Elucidating the Genetic Basis of the Pleuropulmonary Blastoma (PPB) Familial Cancer Syndrome

© 1994- by Medscape.
All Rights Reserved
(http://www.medscape.com/public/copyright)