Abstract
Purpose:
The increased use of abdominal imaging has led to more frequent detection of incidental renal cysts. Since the inception of the Bosniak classification system, management of Bosniak I, III and IV cysts has been clearly defined, while evaluation and management of Bosniak II and IIF cysts have remained a clinical dilemma. Discussions of new imaging modalities are becoming increasingly prevalent in the radiological literature. In this context we performed a comprehensive review of the recent literature on complex renal cysts focusing on new imaging modalities, surveillance strategies and biopsy.
Materials and Methods:
We performed a comprehensive literature review of articles published from January 1, 1998 through December 31, 2013 via MEDLINE®, EMBASE and the Cochrane Collection using a predetermined search strategy. All studies included were performed in humans older than 18 years, were written in English and had an abstract available for review. We grouped studies into 1 of 5 categories, ie computerized tomography, magnetic resonance imaging, ultrasound, biopsy and surveillance.
Results:
While computerized tomography and magnetic resonance imaging with and without contrast enhancement remain the gold standard to evaluate cystic lesions of the kidney, diffusion-weighted magnetic resonance imaging and contrast enhanced ultrasound have surfaced as new tools for assessment of complex cysts. Comparative effectiveness studies on these new imaging modalities are limited. Image guided biopsy has increasingly been shown to be useful for evaluation of intermediate (Bosniak II and IIF) complex cysts. We found few studies providing guidance on the duration and/or intensity of surveillance required for intermediate complex renal cysts.
Conclusions:
Although new and enhanced techniques are in development and may be useful in the future management of complex renal cysts, there is a paucity of data regarding the value of these new techniques. Future research should focus on surveillance of intermediate complex renal cysts, particularly on the ideal frequency and type of imaging required.
References
- 1 : The diagnosis and management of complex renal cysts. Curr Opin Urol2010; 20: 349. Google Scholar
- 2 : The use of the Bosniak classification system for renal cysts and cystic tumors. J Urol1997; 157: 1852. Link, Google Scholar
- 3 : The incidence of simple renal cyst by computed tomography. Clin Radiol1983; 34: 437. Google Scholar
- 4 : Aging and simple cysts of the kidney. Br J Radiol1981; 54: 12. Google Scholar
- 5 : Age-related occurrence of simple renal cysts studied by ultrasonography. Klin Wochenschr1988; 66: 385. Google Scholar
- 6 : Malignant renal cysts: diagnostic performance and strong predictors at MDCT. Acta Radiol2010; 51: 590. Google Scholar
- 7 : Complex renal cystic masses: current standards and controversies. Int Urol Nephrol2012; 44: 13. Google Scholar
- 8 : The characterization of small hypoattenuating renal masses on contrast-enhanced CT. Clin Imaging2009; 33: 295. Google Scholar
- 9 : Differential diagnosis of complex cystic renal mass using multiphase computerized tomography. J Urol2009; 181: 2446. Link, Google Scholar
- 10 : Cystic renal masses: accurate Bosniak classification requires adequate renal CT. AJR Am J Roentgenol2000; 175: 339. Google Scholar
- 11 : Interobserver variability in determining enhancement of renal masses on helical CT. AJR Am J Roentgenol1999; 175: 1207. Google Scholar
- 12 : Differentiation of renal neoplasms from high-density cysts: use of attenuation changes between the corticomedullary and nephrographic phases of computed tomography. J Comput Assist Tomogr2007; 31: 37. Google Scholar
- 13 : Enhancing component on CT to predict malignancy in cystic renal masses and interobserver agreement of different CT features. AJR Am J Roentgenol2006; 186: 665. Google Scholar
- 14 : Distinction of renal cell carcinomas from high-attenuation renal cysts at portal venous phase contrast-enhanced CT. Radiology2003; 228: 330. Google Scholar
- 15 : Detection and characterisation of renal lesions by multiphasic helical CT. Acta Radiol2000; 41: 361. Google Scholar
- 16 : Pseudoenhancement of renal cysts: influence of lesion size, lesion location, slice thickness, and number of MDCT detectors. AJR Am J Roentgenol2012; 198: 133. Google Scholar
- 17 : Renal cysts: is attenuation artifactually increased on contrast-enhanced CT images?. Radiology2000; 216: 792. Google Scholar
- 18 : Evaluation of pseudoenhancement of renal cysts during contrast-enhanced CT. AJR Am J Roentgenol2000; 174: 493. Google Scholar
- 19 : Evaluation of small (≤ 3 cm) renal masses with MDCT: benefits of thin overlapping reconstructions. AJR Am J Roentgenol2004; 183: 223. Google Scholar
- 20 : Delayed computed tomographic characterization of renal masses: preliminary experience. Abdom Imaging2000; 25: 317. Google Scholar
- 21 : Delayed CT to evaluate renal masses incidentally discovered at contrast-enhanced CT: demonstration of vascularity with deenhancement. Radiology1999; 213: 674. Google Scholar
- 22 : Dual-source dual-energy CT evaluation of complex cystic renal masses. AJR Am J Roentgenol2012; 199: 1026. Google Scholar
- 23 : Detection of renal lesion enhancement with dual-energy multidetector CT. Radiology2011; 259: 173. Google Scholar
- 24 : Complex renal cysts: findings on MR imaging. AJR Am J Roentgenol1999; 172: 1495. Google Scholar
- 25 : Diffusion-weighted MRI with parallel imaging technique: apparent diffusion coefficient determination in normal kidneys and in nonmalignant renal diseases. Clin Imaging2010; 34: 432. Google Scholar
- 26 : Ability and utility of diffusion-weighted MRI with different b values in the evaluation of benign and malignant renal lesions. Clin Radiol2011; 66: 420. Google Scholar
- 27 : Diffusion-weighted imaging of the renal and adrenal lesions. J Comput Assist Tomogr2009; 33: 828. Google Scholar
- 28 : Diffusion-weighted magnetic resonance imaging in evaluation of primary solid and cystic renal masses using the Bosniak classification. Eur J Radiol2012; 81: 815. Google Scholar
- 29 : Contrast-enhanced power Doppler sonography for the differentiation of cystic renal lesions: preliminary study. J Ultrasound Med1999; 18: 581. Google Scholar
- 30 : Renal masses—evaluation by amplitude coded colour Doppler sonography and multiphasic contrast-enhanced CT. Acta Radiol1999; 40: 457. Google Scholar
- 31 : Ultrasonography of renal masses using contrast pulse sequence imaging: a pilot study. J Endourol2007; 21: 466. Google Scholar
- 32 : Assessment of cystic renal masses based on Bosniak classification: comparison of CT and contrast-enhanced US. Eur J Radiol2007; 61: 310. Google Scholar
- 33 : Characteristics of renal cystic and solid lesions based on contrast-enhanced computed tomography of potential kidney donors. Am J Kidney Dis2012; 59: 611. Google Scholar
- 34 : Renal complex cysts in adults: contrast-enhanced ultrasound. Abdom Imaging2011; 36: 742. Google Scholar
- 35 : Challenges facing academic urology training programs: an impending crisis. Urology2013; 81: 475. Google Scholar
- 36 : Comparison of contrast-enhanced sonography with unenhanced sonography and contrast-enhanced CT in the diagnosis of malignancy in complex cystic renal masses. AJR Am J Roentgenol2008; 191: 1239. Google Scholar
- 37 : Renal FNA-based typing of renal masses remains a useful adjunctive modality: evaluation of 31 renal masses with correlative histology. Cytopathology2009; 20: 50. Google Scholar
- 38 : CT-guided biopsy of indeterminate renal cystic masses (Bosniak 3 and 2F): accuracy and impact on clinical management. Eur Radiol2002; 12: 2518. Google Scholar
- 39 : Number of needle passes does not correlate with the diagnostic yield of renal fine needle aspiration cytology. J Endourol2008; 22: 2377. Google Scholar
- 40 : Incidence of malignancy in complex cystic renal masses (Bosniak category III): should imaging-guided biopsy precede surgery?. AJR Am J Roentgenol2003; 180: 755. Google Scholar
- 41 : Follow-up CT of moderately complex cystic lesions of the kidney (Bosniak category IIF). AJR Am J Roentgenol2003; 181: 627. Google Scholar
- 42 : Radiographic surveillance of minimally and moderately complex renal cysts. BJU Int2009; 103: 1116. Google Scholar
- 43 : Bosniak category IIF designation and surgery for complex renal cysts. J Urol2009; 182: 1091. Link, Google Scholar
- 44 : FDG PET characterization of renal masses: preliminary experience. Clin Radiol1997; 52: 510. Google Scholar
- 45 : PET-CT-guided percutaneous puncture of an infected cyst in autosomal dominant polycystic kidney disease: case report. Radiology2001; 221: 818. Google Scholar
- 46 : Role of FDG PET/CT in imaging of renal lesions. J Med Imaging Radiat Oncol2010; 54: 347. Google Scholar
