Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Simple and complex renal cysts in adults

Jonathan B Kruskal, MD, PhD
Jerome P Richie, MD, FACS
Section Editor
Ronald D Perrone, MD
Deputy Editor
Alice M Sheridan, MD


Renal cysts result from genetic or nongenetic processes and occur in a variety of diseases in adults and children. The most common causes of radiologically evident renal cysts in adults are simple renal cysts, which will be discussed in this topic review; autosomal dominant polycystic kidney disease (PKD); and acquired cystic disease in patients with end-stage renal disease (ESRD) after several years of dialysis, particularly hemodialysis. (See "Renal manifestations of autosomal dominant polycystic kidney disease" and "Course and treatment of autosomal dominant polycystic kidney disease" and "Acquired cystic disease of the kidney in adults".)

Smaller cysts, usually <1 cm in diameter, also occur in medullary sponge kidney, autosomal recessive PKD, and autosomal dominant interstitial kidney disease (previously called medullary cystic kidney disease). (See "Medullary sponge kidney" and "Autosomal recessive polycystic kidney disease in children" and "Autosomal dominant tubulointerstitial kidney disease (medullary cystic kidney disease)".)

Other unusual causes of renal cysts in adults are von Hippel-Lindau disease, tuberous sclerosis complex, and nephronophthisis. (See "Clinical features, diagnosis, and management of von Hippel-Lindau disease" and "Renal manifestations of tuberous sclerosis complex", section on 'Renal cysts' and "Genetics and pathogenesis of nephronophthisis", section on 'Pathogenesis'.)

An overview of the renal cyst classification system, our recommended approach to complex renal cysts in adults, and a discussion of simple renal cysts are presented in this topic review. The evaluation of a solid renal mass is discussed separately. (See "Diagnostic approach, differential diagnosis, and treatment of a small renal mass".)


Renal cysts are categorized as simple or complex. Simple renal cysts are commonly observed in normal kidneys, with an increasing incidence as individuals age [1]. They are benign, asymptomatic lesions that rarely require treatment. (See 'Simple renal cysts' below.)

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Oct 16, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Lippert MC. Renal Cystic Disease. In: Adult and Pediatric Urology, 4th ed, Gillenwater JY, Grayhack JT, Howards SS, Michell ME (Eds), Lippincott, Williams & Wilkins, Philadelphia 2002. p.8589.
  2. Israel GM, Bosniak MA. An update of the Bosniak renal cyst classification system. Urology 2005; 66:484.
  3. Curry NS, Cochran ST, Bissada NK. Cystic renal masses: accurate Bosniak classification requires adequate renal CT. AJR Am J Roentgenol 2000; 175:339.
  4. Harisinghani MG, Maher MM, Gervais DA, et al. Incidence of malignancy in complex cystic renal masses (Bosniak category III): should imaging-guided biopsy precede surgery? AJR Am J Roentgenol 2003; 180:755.
  5. Smith AD, Allen BC, Sanyal R, et al. Outcomes and complications related to the management of Bosniak cystic renal lesions. AJR Am J Roentgenol 2015; 204:W550.
  6. Goenka AH, Remer EM, Smith AD, et al. Development of a clinical prediction model for assessment of malignancy risk in Bosniak III renal lesions. Urology 2013; 82:630.
  7. Richter F, Kasabian NG, Irwin RJ Jr, et al. Accuracy of diagnosis by guided biopsy of renal mass lesions classified indeterminate by imaging studies. Urology 2000; 55:348.
  8. Israel GM, Bosniak MA. Follow-up CT of moderately complex cystic lesions of the kidney (Bosniak category IIF). AJR Am J Roentgenol 2003; 181:627.
  9. Smith AD, Remer EM, Cox KL, et al. Bosniak category IIF and III cystic renal lesions: outcomes and associations. Radiology 2012; 262:152.
  10. Marotti M, Hricak H, Fritzsche P, et al. Complex and simple renal cysts: comparative evaluation with MR imaging. Radiology 1987; 162:679.
  11. Balci NC, Semelka RC, Patt RH, et al. Complex renal cysts: findings on MR imaging. AJR Am J Roentgenol 1999; 172:1495.
  12. Curry NS, Bissada NK. Radiologic evaluation of small and indeterminant renal masses. Urol Clin North Am 1997; 24:493.
  13. Israel GM, Hindman N, Bosniak MA. Evaluation of cystic renal masses: comparison of CT and MR imaging by using the Bosniak classification system. Radiology 2004; 231:365.
  14. Silverman SG, Gan YU, Mortele KJ, et al. Renal masses in the adult patient: the role of percutaneous biopsy. Radiology 2006; 240:6.
  15. Truong LD, Todd TD, Dhurandhar B, Ramzy I. Fine-needle aspiration of renal masses in adults: analysis of results and diagnostic problems in 108 cases. Diagn Cytopathol 1999; 20:339.
  16. Dechet CB, Zincke H, Sebo TJ, et al. Prospective analysis of computerized tomography and needle biopsy with permanent sectioning to determine the nature of solid renal masses in adults. J Urol 2003; 169:71.
  17. Bosniak MA. The small (less than or equal to 3.0 cm) renal parenchymal tumor: detection, diagnosis, and controversies. Radiology 1991; 179:307.
  18. Bosniak MA. The current radiological approach to renal cysts. Radiology 1986; 158:1.
  19. Clayman RV, Surya V, Miller RP, et al. Pursuit of the renal mass. Is ultrasound enough? Am J Med 1984; 77:218.
  20. Ravine D, Gibson RN, Donlan J, Sheffield LJ. An ultrasound renal cyst prevalence survey: specificity data for inherited renal cystic diseases. Am J Kidney Dis 1993; 22:803.
  21. Slywotzky CM, Bosniak MA. Localized cystic disease of the kidney. AJR Am J Roentgenol 2001; 176:843.
  22. Caglioti A, Esposito C, Fuiano G, et al. Prevalence of symptoms in patients with simple renal cysts. BMJ 1993; 306:430.
  23. Carrim ZI, Murchison JT. The prevalence of simple renal and hepatic cysts detected by spiral computed tomography. Clin Radiol 2003; 58:626.
  24. Terada N, Ichioka K, Matsuta Y, et al. The natural history of simple renal cysts. J Urol 2002; 167:21.
  25. Terada N, Arai Y, Kinukawa N, Terai A. The 10-year natural history of simple renal cysts. Urology 2008; 71:7.
  26. Rule AD, Sasiwimonphan K, Lieske JC, et al. Characteristics of renal cystic and solid lesions based on contrast-enhanced computed tomography of potential kidney donors. Am J Kidney Dis 2012; 59:611.
  27. Glassberg KI. Renal dysgenesis and cystic disease of the kidney. In: Campbell's Urology, 8th ed, Walsh PC, Retik AB, Vaughn ED Jr, Wein AJ (Eds), Saunders, Philadelphia 2002. p.1925.
  28. Chin HJ, Ro H, Lee HJ, et al. The clinical significances of simple renal cyst: Is it related to hypertension or renal dysfunction? Kidney Int 2006; 70:1468.
  29. Pedersen JF, Emamian SA, Nielsen MB. Significant association between simple renal cysts and arterial blood pressure. Br J Urol 1997; 79:688.
  30. Ekart R, Hojs R, Krajnc I. [Simple renal cysts and hypertension]. Wien Klin Wochenschr 2001; 113 Suppl 3:43.
  31. Holmberg G, Hietala SO, Karp K, Ohberg L. Significance of simple renal cysts and percutaneous cyst puncture on renal function. Scand J Urol Nephrol 1994; 28:35.
  32. Al-Said J, Brumback MA, Moghazi S, et al. Reduced renal function in patients with simple renal cysts. Kidney Int 2004; 65:2303.
  33. Papanicolaou N, Pfister RC, Yoder IC. Spontaneous and traumatic rupture of renal cysts: diagnosis and outcome. Radiology 1986; 160:99.
  34. Babka JC, Cohen MS, Sode J. Solitary intrarenal cyst causing hypertension. N Engl J Med 1974; 291:343.
  35. Lüscher TF, Wanner C, Siegenthaler W, Vetter W. Simple renal cyst and hypertension: cause or coincidence? Clin Nephrol 1986; 26:91.
  36. Edwards EC, Farrar DJ. Pelvi-ureteric obstruction due to renal pelvis cyst. Eur Urol 1977; 3:163.
  37. Curry NS. Small renal masses (lesions smaller than 3 cm): imaging evaluation and management. AJR Am J Roentgenol 1995; 164:355.
  38. Fontana D, Porpiglia F, Morra I, Destefanis P. Treatment of simple renal cysts by percutaneous drainage with three repeated alcohol injection. Urology 1999; 53:904.
  39. Akinci D, Akhan O, Ozmen M, et al. Long-term results of single-session percutaneous drainage and ethanol sclerotherapy in simple renal cysts. Eur J Radiol 2005; 54:298.
  40. Zerem E, Imamovíc G, Omerovíc S. Symptomatic simple renal cyst: comparison of continuous negative-pressure catheter drainage and single-session alcohol sclerotherapy. AJR Am J Roentgenol 2008; 190:1193.
  41. Atug F, Burgess SV, Ruiz-Deya G, et al. Long-term durability of laparoscopic decortication of symptomatic renal cysts. Urology 2006; 68:272.
  42. Muther RS, Bennett WM. Concentration of antibiotics in simple renal cysts. J Urol 1980; 124:596.