Cystic Renal Masses: Old and New Paradigms.

Cystic renal masses describe a spectrum of lesions with benign and/or malignant features. Cystic renal masses are most often identified incidentally with the Bosniak classification system stratifying their malignant potential. Solid enhancing components most often represent clear cell renal cell carcinoma yet display an indolent natural history relative to pure solid renal masses. This has led to an increased adoption of active surveillance as a management strategy in those who are poor surgical candidates. This article provides a contemporary overview of historical and emerging clinical paradigms in the diagnosis and management of this distinct clinical entity.

Using Contrast-Enhanced Ultrasound in Addition to Cross-Sectional Imaging for Indeterminate Renal Cysts May Lead to Overclassification in Bosniak III Category: A Case-Control Study.

INTRODUCTION: Indeterminate renal cysts may require several imaging modalities before clinical decision. The aim of this study was to investigate the effect of the imaging modality used to characterize indeterminate renal cysts on the pathological findings after surgical resection. METHODS: From our institutional database, we identified all patients surgically treated for Bosniak III renal masses between January 2008 and January 2018. All complex renal cysts were characterized with a combination of computed tomography (CT) and/or magnetic resonance imaging (MRI), and/or contrast-enhanced ultrasound (CEUS) and discussed during a multidisciplinary tumor board. Potential association between clinical/radiological characteristics and the pathological findings were investigated, using univariate and multivariate analyses. RESULTS: Of the 52 renal cystic lesions surgically removed, with a preoperative diagnosis of Bosniak III renal cyst, 19 (37%) were malignant and 33 (63%) were benign. The proportion of malignant lesions decreased from 47% when the renal cyst was characterized with cross-sectional imaging (CT and/or MRI) to 17% when the diagnosis required CEUS in addition to cross-sectional imaging. In multivariate analysis, prior history of renal cell carcinoma was associated with a higher risk of malignancy (p = 0.016) and diagnosis made with CEUS was associated with a lower risk of malignancy (p = 0.040). CONCLUSION: We found that using CEUS in addition to cross-sectional imaging to characterize indeterminate renal cysts tends to redefine Bosniak III as lesions with a lower risk of malignancy and can lead to overclassification.

Multi-disciplinary team conference clarifies bosniak classification of complex renal cysts.

OBJECTIVES: The aims of this study are to determine the progression rate of Bosniak IIF cysts, the malignancy rates of complex renal cysts in patients undergoing surgery and explore the influence of multi-disciplinary team conference (MDT) on re-classification of Bosniak cysts. MATERIALS AND METHODS: All CT scans from January 2010 to 2017 were pooled into a database. Initially, 167 patients were identified with possible Bosniak IIF, III or IV cysts. Patients with follow up of less than 24 months, without progression or regression were excluded. RESULTS: Thirty-one (18.6%) cysts of the initial 167 cysts were either up or downgraded at a MDT. Twenty-six of the 31 cysts were up or downgraded at the primary MDT, 13 cysts (50%) were downgraded, five cysts (19.2%) were upgraded and eight cysts (30.8%) were re-classified as solid tumors. Of those 19/26 (73.1%) were primary interpreted by a periphery radiologist and re-classified centrally. The last five patients 5/120 cysts (4.2%) were re-classified during follow up. 116 patients with a total of 120 cysts met the inclusion criteria, 79 (65.8%) Bosniak IIF, 28 (23.3%) Bosniak III and 13 (10.8%) Bosniak IV cysts represented. Median follow up of Bosniak IIF cysts were 46 months. One Bosniak IIF cyst progressed to a solid tumor at 15 months from diagnosis, progression rate 1.3%. Histopathology was papillary renal cell carcinoma. Malignancy rates of Bosniak III and IV cysts were 50% and 78%, respectively. CONCLUSION: Multi-disciplinary team conference may have an important role in correct classification of Bosniak cysts. TRIAL REGISTRATION: None.

Management of complex renal cysts in Canada: results of a survey study.

BACKGROUND: Bosniak III and IV cysts have a high risk of malignancy and have traditionally been managed surgically. However, growing evidence suggests that many can be managed by active surveillance. The main objective of this study was to characterize the use of surveillance in the management of complex renal cysts. METHODS: A web-based survey was sent to all registered, active members of the Canadian Urological Association (N = 583) in October 2018. RESULTS: The survey response rate was 24.7%. Management of Bosniak III cysts varied considerably. A large proportion of respondents (33.1%) offered active surveillance in > 50% of cases. Only 13.7% of respondents reported never or rarely (< 5% of cases) offering surveillance. In contrast, for Bosniak IV cysts, 60.1% of urologists never or rarely offered surveillance, while only 10.1% offer it in > 50% of cases. A significantly greater proportion of academic urologists, compared to non-academic urologists, viewed surveillance as a management option for patients with a Bosniak III or IV cyst. The most commonly reported barriers to a greater adoption of surveillance were concerns regarding its oncologic safety, the lack of data to support surveillance in this population, and the lack of triggers for discontinuation of active surveillance and intervention. CONCLUSIONS: Despite active surveillance being included as a management option in guidelines, many Canadian urologists are reluctant to offer surveillance to patients with Bosniak III or IV cysts. Practice patterns are heterogeneous among those offering surveillance. High-quality studies are required to better define the benefits and risks of cystic renal mass surveillance.

Application value of contrast-enhanced ultrasound in differential diagnosis of complex renal cysts and clear renal cell carcinoma with cystic change / 中华超声影像学杂志

Objective To investigate the value of contrast-enhanced ultrasound(CEUS)in differential diagnosis of complex renal cysts and clear renal cell carcinoma with cystic change(CRCCC).Methods The ultrasonographic datas of 82 lesions in 82 patients with complicated renal cysts or CRCCC confirmed by pathology were analyzed.The characteristics of conventional ultrasound and CEUS were observed and evaluated.The lesions were graded according to Bosniak classification criteria.Results Pathological examination showed that 36 cases were complicated renal cysts and 46 cases were CRCCC. Routine ultrasound showed there were 9 cases (25.0％) with cystic masses and 27 cases (75.0％) with solid and cystic masses in complex renal cysts,of which 14 cases (38.9％) could detect color flow signals.In CRCCC,2 cases(4.3％)were with cystic masses and 44 cases(95.7％)were with solid and cystic masses, of which 33 cases(75.0％)could detect color flow signals.CEUS showed that only 18 cases(50.0％)of the complex renal cysts showed enhancement of cystic wall or septum,with equal or low enhancement at the peak,9 cases(50.0％) accompanied by decrease of renal cortex,35 cases (97.2％) had thin and regular cystic wall,no enhancement of cystic wall in all lesions,and 33 cases(91.7％)had septal thickness less than 1 mm.Forty-five cases (97.8％) of CRCCC showed enhancement of cystic wall or septum,40 cases(88.9％)showed equal or high enhancement at peak,30 cases(66.7％)were faster than the decrease of renal cortex,37 cases (80.4％) showed uneven thickness of cystic wall,24 cases (52.2％) showed enhancement of cystic wall nodules,and 28 cases (60.9％) showed uneven thickness of septum.After CEUS,33 cases(91.7％)of complex renal cysts were classified as grade Ⅰ and Ⅱ,while 42 cases(91.3％) of CRCCC were classified as grade Ⅲ and Ⅳ.Conclusions The CEUS manifestations of complex renal cysts are different from those of CRCCC.The application of Bosniak criteria in CEUS is helpful for the differential diagnosis of complex renal cysts and CRCCC.

Application value of contrast-enhanced ultrasound in differential diagnosis of complex renal cysts and clear renal cell carcinoma with cystic change / 中华超声影像学杂志

Objective@#To investigate the value of contrast-enhanced ultrasound(CEUS) in differential diagnosis of complex renal cysts and clear renal cell carcinoma with cystic change(CRCCC).@*Methods@#The ultrasonographic datas of 82 lesions in 82 patients with complicated renal cysts or CRCCC confirmed by pathology were analyzed. The characteristics of conventional ultrasound and CEUS were observed and evaluated. The lesions were graded according to Bosniak classification criteria.@*Results@#Pathological examination showed that 36 cases were complicated renal cysts and 46 cases were CRCCC. Routine ultrasound showed there were 9 cases (25.0%) with cystic masses and 27 cases (75.0%) with solid and cystic masses in complex renal cysts, of which 14 cases (38.9%) could detect color flow signals. In CRCCC, 2 cases (4.3%) were with cystic masses and 44 cases (95.7%) were with solid and cystic masses, of which 33 cases (75.0%) could detect color flow signals. CEUS showed that only 18 cases (50.0%) of the complex renal cysts showed enhancement of cystic wall or septum, with equal or low enhancement at the peak, 9 cases (50.0%) accompanied by decrease of renal cortex, 35 cases (97.2%) had thin and regular cystic wall, no enhancement of cystic wall in all lesions, and 33 cases (91.7%) had septal thickness less than 1 mm. Forty-five cases (97.8%) of CRCCC showed enhancement of cystic wall or septum, 40 cases (88.9%) showed equal or high enhancement at peak, 30 cases (66.7%) were faster than the decrease of renal cortex, 37 cases (80.4%) showed uneven thickness of cystic wall, 24 cases (52.2%) showed enhancement of cystic wall nodules, and 28 cases (60.9%) showed uneven thickness of septum. After CEUS, 33 cases (91.7%) of complex renal cysts were classified as grade Ⅰ and Ⅱ, while 42 cases (91.3%) of CRCCC were classified as grade Ⅲ and Ⅳ.@*Conclusions@#The CEUS manifestations of complex renal cysts are different from those of CRCCC. The application of Bosniak criteria in CEUS is helpful for the differential diagnosis of complex renal cysts and CRCCC.

Contrast-enhanced ultrasound for characterizing renal masses.

On cross-sectional imaging studies performed for other indications, incidental discovery of renal lesions is not uncommon. In daily use, grey-scale ultrasonography (US) and conventional Doppler modes are often the modality of choice for the initial assessment. While simple cysts are fully characterized with US, other lesions require further characterization, which is traditionally obtained by multiphase imaging, such as contrast-enhanced CT and MRI. Contrast-enhanced ultrasound (CEUS) has become a powerful additional tool for imaging renal lesions. With its lack of nephrotoxicity, the absence of ionizing radiation, and the ability to evaluate the enhancement pattern of renal lesions quickly and in real- time, CEUS has unique advantages over traditional modes. Established applications are differentiation between solid tumours, pseudolesions, and complex cysts; characterization of complex cysts with different malignant potential, and evaluation of tumor ablation. Microbubble contrast agents are safe. Adverse reactions are rare. This article provides an overview of the current clinical applications of CEUS in characterizing renal masses, discussing advantages and limitations. The aim is to provide the framework for sonologists to make informed decisions regarding this emerging imaging test in appropriate circumstances.

Regression of Crizotinib-Associated Complex Cystic Lesions after Switching to Alectinib.

Crizotinib, which is effective in patients with anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer, is sometimes associated with the generation of complex renal cysts. A 56-year-old man with ALK positive adenocarcinoma received crizotinib. Ten months after the introduction of crizotinib, a cystic lesion developed from his right kidney to the iliopsoas muscle, accompanied by fever, anemia, and hypoproteinemia. After 17 months of treatment, crizotinib was switched to alectinib, followed by the recovery of hypoproteinemia and systemic inflammation. Switching to alectinib may be beneficial in patients demonstrating crizotinib-associated complex renal cysts with systemic inflammation and exhaustion.

The role of contrast-enhanced ultrasound in the classification of CT-indeterminate renal lesions.

OBJECTIVE: Focal renal lesions are common incidental findings on computed tomography (CT). For lesions with a cystic appearance, the Bosniak classification system has enabled an important separation of benign and (potentially) malignant cysts, giving a practical guide for management. The purpose of this study was to evaluate contrast-enhanced ultrasound (CEUS) as a problem-solving modality for classification of indeterminate renal lesions detected with CT. MATERIALS AND METHODS: In total, 140 consecutive patients with 148 indeterminate renal lesions were examined with ultrasound combined with CEUS (81 men and 59 women with mean age 63.8 years). RESULTS: Altogether, 146 lesions were classified by CEUS in categories according to the Bosniak classification system, or as solid lesions. Mean lesion diameter was 30 mm (range 5-166 mm). Nine lesions were classified as category I, 32 as category II and 59 as category IIF ("non-surgical lesions"). 48 IIF cysts were followed for a minimum of 2 years (mean 4 years and 8 months): three lesions were upgraded to category III (6%) and 45 were stable category. 19 lesions had a more complex cystic appearance: 12 were classified as category III and seven as category IV cysts. 27 lesions were diagnosed as solid, enhancing tumors. In total, 25 patients with lesions of category III, IV and solid ("surgical lesions") underwent renal surgery, with malignancy diagnosed in 18. CONCLUSION: In the common setting of indeterminate renal lesions incidentally detected with a CT exam, CEUS has the potential to classify lesions into "non-surgical" and "surgical" categories, providing a platform for urological decision making, while avoiding radiation exposure.

Diagnosis and evaluation of renal cysts.

Renal cysts are commonly encountered in clinical practice. Although most cysts found on routine imaging studies are benign, there must be an index of suspicion to exclude a neoplastic process or the presence of a multicystic disorder. This article focuses on the more common adult cystic diseases, including simple and complex renal cysts, autosomal-dominant polycystic kidney disease, and acquired cystic kidney disease.