Renal Cyst Puncture Studies

Contrast-enhanced ultrasound of the kidney: a single-institution experience

BACKGROUND

Focal renal masses are typically evaluated by means of triphasic contrast-enhanced CT or MRI scan but use of iodinated contrast or gadolinium is unsuitable for some patients. Contrast-enhanced ultrasound (CEUS) is an imaging alternative in this scenario but has limited availability in Ireland.

AIM

The aim of the study was to retrospectively evaluate experience with selective use of CEUS for non-invasive characterization of focal renal masses in a tertiary referral institution in Ireland, with a particular focus on cystic renal lesions and the influence of CEUS on final Bosniak classification and treatment outcomes.

METHODS

All cases of renal CEUS between 2009 and 2017 were identified. Imaging history, patient records, histopathology reports, urology conference notes, clinical follow-up details, details of lesion progression or stability on surveillance, biopsy and/or resection details and pre- and post-CEUS Bosniak scores were recorded.

RESULTS

Thirty-one patients underwent renal CEUS (7 solid renal lesions, 21 cystic renal lesions and 3 'indeterminate' renal lesions). After CEUS, the CEUS-modified Bosniak score was upgraded in nine patients and downgraded in two patients. All three lesions upgraded from Bosniak III to IV were renal cell carcinomas. One of two lesions downgraded from Bosniak IV to III was resected (cystic nephroma) and the other showed no progression after 19 months of surveillance.

CONCLUSION

CEUS is a valuable alternative to CT in assessing complex cystic or solid renal lesions where iodinated CT contrast or gadolinium is inappropriate. CEUS can also refine the Bosniak category of atypical cystic renal lesions and help facilitate treatment decisions.

Imaging and Screening of Kidney Cancer

Renal cell carcinoma (RCC) exhibits a diverse and heterogeneous disease spectrum, but insight into its molecular biology has provided an improved understanding of potential risk factors, oncologic behavior, and imaging features. Computed tomography (CT) and MR imaging may allow the identification and preoperative subtyping of RCC and assessment of a response to various therapies. Active surveillance is a viable management option in some patients and has provided further insight into the natural history of RCC, including the favorable prognosis of cystic neoplasms. This article reviews CT and MR imaging in RCC and the role of screening in selected high-risk populations.

Genitourinary cytopathology (kidney and urinary tract)

FNA of kidney masses have been performed for the diagnosis of mass lesions,confirmation of advanced neoplasia and metastases, and staging of tumors. In the past, the decision of whether to perform a nephrectomy used to be based on radiographic features and size, precluding the use of FNA. Today, where treatment is not limited to surgery alone, the indications for renal FNA have expanded. Most small renal masses are asymptomatic and are detected incidentally due to improved imaging techniques. Although most urologists agree that the standard of care for renal masses is surgery, if the patient is an elderly individual, or has comorbidities a preoperative FNA could be useful in guiding the management.When we look at data from large referral institutions such as Mayo Clinic, Johns Hopkins Medical Institutions, and the Cleveland Clinic approximately 30 %of the renal masses are benign [86---88]. Therefore, as astutely pointed out by Volpe et al.[3], there is a role for precise pretreatment characterization of the renal masses by FNA, which would decrease the unnecessary treatment for benign diseases and reduce the treatment-related mortality and morbidity in addition to reducing patient care costs.To date, urine cytology remains the gold standard for bladder cancer screening.It has been, and still is, the test against which all new tests are compared when evaluating potential bladder tumor markers. The answer to whether urine cytology possesses the optimal combination of sensitivity and specificity to retain consideration as the best screening device depends on the goals of the practice. Urine cytology has excellent specificity with only few false-positive cases. Its overall sensitivity (including both high grade and low grade lesions) is poor, but this is explained by poor criteria for identifying well-differentiated, low-grade urothelial carcinoma in cytology. The natural history of low grade lesions is that of multiple superficial recurrences in 70 - 80 % of patients, with only a minority ( 10-15 %)progressing to muscle invasive or metastatic disease [89]. Patients with low-grade urothelial carcinoma are at low risk for progression, they are monitored primarily for the development of a subsequent high grade tumor [90]. Therefore, as suggested by Koss, detection of new low-grade lesions may be clinically irrelevant as compared to early detection of disease progression [39]. Contrary to the low grade lesions, however, urine cytology often results in the identification of high-grade malignant cells even before a cystoscopically distinguishable gross lesion is present. In the last 20 years, a number of noninvasive test have been developed to detect urothelial carcinoma. Although some have been able to show a better sensitivity compared to cytology, only a few have been close to reaching the sensitivity seen in cytology. Most of these tests have not added much to the diagnostic evaluation. Combining some of the new markers with each other and/or cytologic evaluation may optimize their performance status.

Evaluation of indeterminate renal masses with contrast-enhanced US: a diagnostic performance study

PURPOSE

To determine the utility of contrast material-enhanced ultrasonography (US) in the characterization of indeterminate renal masses.

MATERIALS AND METHODS

This retrospective performance study was approved by the institutional review board and was HIPAA compliant, with waiver of informed consent. Patients included 721 individuals referred for contrast-enhanced US with 1018 indeterminate renal masses from 1999 to 2010, identified initially with an imaging study. Three hundred twenty patients (44.4%) were female, and 401 (55.6%) were male. Patient ages ranged from 17 to 95 years (mean ± standard deviation, 70 years ± 15). Lesion size varied from 2 to 161 mm (mean, 26.6 mm ± 19.5). Contrast-enhanced US enhancement patterns were used to characterize masses as benign or malignant. For lesions with a definitive diagnosis, 306 of 1018 (30.0%) were correlated with contrast-enhanced US findings: 167 (54.6%) were benign, and 139 (45.4%) were malignant. For lesions without a pathologic diagnosis, 712 (70.0%) were followed for as long as 10 years. Diagnostic accuracy measures were calculated by using pathologic diagnosis as the reference standard, as well as lesion stability at 3 and 5 years.

RESULTS

Contrast-enhanced US had a sensitivity of 100% (126 of 126; 95% confidence interval [CI]: 97.1%, 100%), specificity of 95.0% (132 of 139; 95% CI: 89.9%, 98.0%), positive predictive value (PPV) of 94.7% (126 of 133), and negative predictive value (NPV) of 100% (132 of 132). The five false-positive masses included three oncocytomas and two Bosniak category 3 cystic lesions. Of the 290 lesions that had follow-up of at least 36 months, none of the lesions demonstrated changes that necessitated lesion reclassification. If these lesions were included, assuming lesions classified as malignant were malignant, then of the 596 lesions, sensitivity was 100% (161 of 161), specificity was 96.6% (420 of 435), PPV was 91.5% (161 of 176), and NPV was 100% (420 of 420).

CONCLUSION

Contrast-enhanced US evaluation is a highly sensitive and specific method for characterization of indeterminate renal masses. Online supplemental material is available for this article.

The role of percutaneous renal biopsy in the management of small renal masses

The use of percutaneous renal mass biopsy (RMB) has increased in recent years, likely in parallel with the growing incidence of renal cell carcinoma and small renal masses in particular. Biopsy and imaging techniques are improving, and diagnostic sufficiency and accuracy of RMB now are much higher in large-volume, experienced centers. Overall morbidity is low. This has led to a significant expansion of the indications for biopsy beyond documenting renal involvement for patients with metastatic disease or other systemic illnesses. While there still are limitations to its use and clinical judgment is paramount, RMB is proving to be a valuable tool in the clinical diagnosis and management of small renal masses.

Renal mass sampling: an enlightened perspective

Renal mass sampling (RMS) can be carried out by core biopsy or fine needle aspiration with each presenting potential advantages and limitations. The literature about RMS is confounded by a lack of standardized techniques, ambiguous terminology, imprecise definitions of accuracy, substantial rates of non-informative biopsies, and recurrent diagnostic challenges with respect to eosinophilic neoplasms. Despite these concerns, RMS has an expanding role in the evaluation and treatment of renal masses, in order to stratify biological aggressiveness and guide management that can range from surgery to active surveillance. Non-informative biopsies can be managed with surgical excision or repeat biopsy, with the latter showing encouraging results in recent studies. We propose a new classification in which all biopsies are categorized as non-informative versus informative, with the latter being subclassified as confirmed accurate, presumed accurate or confirmed inaccurate. This terminology will facilitate the comparison of results from various studies and stimulate progress. Incorporation of novel biomarkers and molecular fingerprinting into RMS protocols will likely allow for more rational management of patients with renal masses in the near future.

Percutaneous resection of renal cysts

Symptomatic renal cysts can be managed endoscopically via retrograde ureterorenoscopy, antegrade percutaneous nephroscopy, or laparoscopy. Although all three methods are minimally invasive and effective, the retrograde approach is limited by the size and location of the cyst. Laparoscopy is also effective but is associated with multiple port sites, extensive dissection, and technical difficulty. We utilize percutaneous trans-parenchymal endocystolysis as a first-line therapy. The technique is described in detail.

Renal cystic disease. Laparoscopic management

Laparoscopy offers a safe and efficacious means of ablating symptomatic simple renal cysts while conferring the usual benefits of shorter hospital stay, quicker convalescence, and reduced postoperative pain, although no direct comparison with open surgery has been performed. For indeterminate, complex renal cysts, laparoscopic exploration may spare the patient a morbid open operation to assess a cystic lesion of indeterminant risk. Although laparoscopic removal of kidneys with ADPKD remains a technically challenging exercise, centers of laparoscopic expertise have demonstrated the safety and feasibility of the procedure, thereby expanding the benefits of laparoscopic surgery to patients traditionally relegated to open surgical management.

Cystic renal cell carcinoma diagnosed by cystofiberscopy

A 64-year-old man suffered from hypertensive syncope and was admitted to Branch Hospital, Faculty of Medicine, The University of Tokyo. On admission he had no symptoms; however, two renal cysts of about 5 cm in diameter were found in his left kidney. Cystofiberscopy with a thin optical fiberscope was performed in addition to puncture and cystography. Cytology revealed class I, but the wall surface of the lower cyst was uneven, fluid-filled, colloid-like and white-gray compared with that seen in the upper cyst. It was diagnosed as renal cell carcinoma (RCC) and left nephrectomy was performed (5 cm in diameter, RCC, papillary tubular, common, clear cell subtype, G2>G1, INF beta, pT2, pMx, pV0, ew(-)).

Accuracy of diagnosis by guided biopsy of renal mass lesions classified indeterminate by imaging studies

OBJECTIVES

To define the accuracy, safety, and impact of percutaneous biopsies of indeterminate mass lesions as an additional diagnostic tool. The vast majority of renal mass lesions are routinely diagnosed by radiographic features alone. However, with the increased use of computed tomography scanning and ultrasound, many smaller renal masses, which are "indeterminate" (refractory to categorization on the basis of imaging alone), are now being discovered.

METHODS

We retrospectively reviewed 583 patients (364 male and 219 female) with indeterminate renal mass lesions diagnosed by imaging studies that were further investigated by percutaneous biopsy. Patients were followed up for at least 5 years if the biopsy result demonstrated a benign lesion, or they underwent surgical exploration if the biopsy result demonstrated a malignancy. Biopsy or aspiration material was assessed by histopathologic and cytologic evaluation and, when appropriate, with biochemistry, Gram stain, culture, and sensitivity. The biopsy site was localized by computed tomography, ultrasound, or fluoroscopy.

RESULTS

Five hundred eighty-three patients with indeterminate renal mass lesions (representing 7.2% of all renal masses diagnosed from 1967 through 1996) were diagnosed by imaging studies complemented by guided biopsy. Sixty-six patients were lost to follow-up, leaving 517 patients who were analyzed. In 393 cases (76%), the imaging-guided biopsy provided a definitive diagnosis. The incidence of false diagnoses was 1.2% (7 biopsies). In 124 of the cases (21%), imaging-guided biopsy was unable to determine the etiology of the lesion with acceptable confidence; of these, 21 biopsies did not provide enough material to establish the diagnosis (16.9%).

CONCLUSIONS

Overall, percutaneous biopsy of the kidney has proved to be a safe and accurate diagnostic procedure, with impact on the management of cystic or solid renal lesions.

Fine-needle aspiration of renal masses in adults: analysis of results and diagnostic problems in 108 cases

Fine-needle aspiration (FNA) biopsy of the kidney has a traditionally well-defined role in the diagnosis and treatment of renal lesions. Recent improvements in renal imaging techniques have also brought renal FNA to the forefront, since small and asymptomatic renal masses are increasingly being detected. Before the physician institutes a treatment plan, such lesions usually require a definitive diagnosis that is best provided by FNA. To assess various aspects of renal FNA, including specimen adequacy, questionable cytologic patterns, and diagnostic pitfalls, we retrospectively evaluate our experience with 108 FNA biopsies performed for the evaluation of renal masses in adults. For each case, the smears were reviewed and correlated with tissue sections from cell blocks, surgical specimens, or autopsy material, when available. The cytologic diagnoses were confirmed by cell block (59 cases), nephrectomy or autopsy (35 cases), or clinical follow-up. Of the 108 FNA biopsy samples, 17 showed evidence of blood, soft tissue, necrotic material, glomeruli, or tubular cells and were classified as unsatisfactory. The following diagnostic categories were noted in the 91 satisfactory aspirates: renal abscess (four cases), benign cyst (30 cases), suspicious lesions (11 cases), and malignant lesions (46 cases). In four cases of renal abscess, FNA found abundant clusters of neutrophils. For the 30 cases interpreted on cytologic evidence as benign cysts, the diagnosis was confirmed in 28 cases; the two remaining cases were acquired cystic kidney and cystic renal-cell carcinoma, respectively. Among the 11 suspicious lesions, the final diagnoses were one benign simple cyst, one angiomyolipoma, two multilocular cystic nephromas, two adult polycystic kidneys, one acquired cystic kidney, three cystic papillary renal-cell carcinomas, and one solid renal-cell carcinoma. Cases classified as suspicious shared characteristic cytologic patterns that distinguished them from simple benign cysts and from classic renal-cell carcinoma. Among the 46 malignant lesions, as evidenced on cytologic examination, 27 were renal-cell carcinomas, five were transitional-cell carcinomas, four were lymphomas, one was a small-cell undifferentiated carcinoma, and nine were metastatic carcinomas. False-positive or false-negative cases were not encountered in this category. In conclusion, FNA is an excellent method to diagnose space-occupying lesions of the kidney. For cystic lesions, cytologic-radiographic correlation is needed to avoid misinterpretation. Our study defines a spectrum of suspicious patterns characteristic of a group of renal lesions that are distinct from both benign simple cyst and straightforward renal malignancy.

Diagnostic difficulties in the interpretation of needle aspiration material from large renal cysts

In recent years, fine-needle-aspiration biopsies (FNA) have been widely used in the evaluation of renal masses, with false-positive FNA data being very uncommon. We present a case report of a 76-yr-old man with a 16-cm renal cyst and what was interpreted as an isolated calcified mural nodule. Following drainage of the main cyst fluid, FNA biopsy showed atypical cell clusters thought to be positive for malignancy. Subsequent surgery failed to disclose either a residual mural nodule or evidence of malignancy. Immunoperoxidase studies performed on both the cell block and actual cyst wall suggested that the abnormal cells were histiocytes. The diagnostic pitfalls of this case, along with a review of pertinent literature, are discussed.

Laparoscopic unroofing of simple renal cysts

OBJECTIVE

The aim of this study was to assess the clinical reliability of laparoscopic treatment for simple renal cysts.

METHODS

Twenty patients with symptomatic simple renal cysts underwent laparoscopic unroofing of the cysts. Four of these patients also underwent concomitant laparoscopic cholecystectomy because of symptomatic gallbladder stones.

RESULTS

In all cases the cyst wall was widely resected with no significant surgical complication. Cholecystectomy was easily performed without additional morbidity. Postoperative renal ultrasonography and intravenous urography demonstrated the absence of cyst recurrences and the integrity of the excretory tract. Symptoms were resolved by the operation in all cases.

CONCLUSIONS

Laparoscopic unroofing is a safe, effective, and minimally invasive treatment for selected symptomatic simple renal cysts.

Laparoscopic retroperitoneal renal cystectomy

Laparoscopic manipulation of retroperitoneal organs is usually performed by the transperitoneal approach primarily because of the ease of access by way of the pneumoperitoneum. However, difficulty in adequately accessing structures that are surrounded by bowel, liver, spleen or postoperative adhesions makes this approach suboptimal in certain cases. We describe the use of the retroperitoneal laparoscopic approach to the upper pole of a kidney for marsupialization of a symptomatic, recurrent, complex renal cyst. An algorithm for current management of symptomatic renal cysts is discussed.

Ureteronephroscopic marsupialization of obstructing peripelvic renal cyst

Flexible ureteronephroscopy has been used for numerous therapeutic applications in the upper urinary tract. We report a case of a large peripelvic renal cyst causing obstruction to the ureteropelvic junction, which was treated by incising the wall of the cyst into the renal pelvis with the ureteronephroscope.