Validation of the updated Bosniak classification (2019) in pathologically confirmed CT-categorised cysts.

INTRODUCTION: The updated Bosniak classification in 2019 (v2019) addresses vague imaging terms and revises the criteria with the intent to categorise a higher proportion of cysts in lower-risk groups and reduce benign cyst resections. The aim of the present study was to compare the diagnostic accuracy and inter-observer agreement rate of the original (v2005) and updated classifications (v2019). METHOD: Resected/biopsied cysts were categorised according to Bosniak classifications (v2005 and v2019) and the diagnostic accuracy was assessed with reference to histopathological analysis. The inter-observer agreement of v2005 and v2019 was determined. RESULTS: The malignancy rate of the cohort was 83.6% (51/61). Using v2019, a higher proportion of malignant cysts were categorised as Bosniak ≥ III (88.2% vs 84.3%) and a significantly higher percentage were categorised as Bosniak IV (68.9% vs 47.1%; p = 0.049) in comparison to v2005. v2019 would have resulted in less benign cyst resections (13.5% vs 15.7%). Calcified versus non-calcified cysts had lower rates of malignancy (57.1% vs 91.5%; RR,0.62; p = 0.002). The inter-observer agreement of v2005 was higher than that of v2019 (kappa, 0.70 vs kappa, 0.43). DISCUSSION: The updated classification improves the categorisation of malignant cysts and reduces benign cyst resection. The low inter-observer agreement remains a challenge to the updated classification system.

[Effect of a simple kidney cyst on renal function].

INTRODUCTION: Renal cysts are a common disease that occurs at a rate of 7-10%. Currently there are no clinical recommendations for the treatment of patients with simple renal cysts. In the current literature there is some evidence that a simple renal cyst has negative effects on renal function. Decreased renal function occurs due to partial atrophy and loss of the renal parenchyma (in the "crater" area at the base of the cyst) caused by compression. Therefore, the efforts to analyze the effect of simple kidney cysts on kidney function and identify the characteristics of the cyst that affect renal function to determine the indications for surgical treatment remains a substantial task. The aim of the study was to analyze the effect of simple renal cysts on renal function, to investigate the relationship between cyst size, atrophied parenchyma volume, and renal function, and to determine indications for surgical treatment of simple renal cysts. MATERIALS AND METHODS: We conducted a prospective cohort study. The study included 109 patients with simple renal cysts. Patients with a solitary cyst of the right or left renal kidney, grade I-II according to Bosniak classification, were included in the study. The estimated glomerular filtration rate (eGFR) of the patients was calculated using various formulas. A contrast CT scan of the urinary tract was also performed to determine the maximum size of the cyst, calculate the volume of the renal parenchyma, and the volume of the lost (atrophied) parenchyma. Patients underwent renal scintigraphy with calculation of total GFR and split renal function. We analyzed the symmetry of the function of both kidneys by comparing the GFR of the affected and healthy kidneys, analyzed the relationship between the presence of a kidney cyst and a decrease in GFR, between the maximum size of a renal cyst and a decrease in its function compared with that of a healthy kidney. We also analyzed the correspondence of total GFR values obtained in renal scintigraphy and GFR values calculated according to the formulas. RESULTS: Data from 109 patients were available for analysis; the mean blood creatinine was 87.4 mol/L. The median maximum cyst size was 80 mm. The median baseline volume of the affected kidney parenchyma was 174 ml, the median volume of the lost parenchyma was 49 ml, and the median proportion of the lost parenchyma was 28%. The median total GFR was 77.07 ml/min. The median GFR of the healthy kidney was 45.49 mL/min, and the median GFR of the kidney affected by the cyst was 34.46 mL/min. The median difference in GFR of the healthy and affected kidney units was 11 mL/min and was statistically significant. Comparison of the eGFR values obtained by the formulas with the reference values of GFR obtained by scintigraphy showed that the Cockcroft-Gault formula with standardization on the body surface area calculated closest eGFR values to the reference ones. Correlation analysis revealed a statistically significant association between the proportion of lost parenchyma volume and the maximum cyst size: =0.37 with 95% CI [0.20; 0.52] (p-value = 0). A multivariate logistic regression model revealed that a statistically significant factor influencing the probability of a significant decrease in GFR was the percent of lost renal parenchyma volume (OR=1,13; =0). CONCLUSIONS: Our study showed that growth of renal cysts associated with renal parenchyma atrophy and decrease of GFR of the affected kidney. An increase in the volume of atrophied parenchyma leads to the decrease in GFR of the affected kidney. The obtained data suggest that performing dynamic renal scintigraphy to assess the decrease in affected renal function and determine the indications for surgical treatment of renal cysts is a reasonable recommendation. According to the results of the study, the loss of 20% of the renal parenchyma can be considered an indication for renal scintigraphy. The Cockcroft-Gault formula with standardization on the body surface area allows to calculate closest GFR values to those obtained by scintigraphy and, therefore, can be recommended as the optimal formula for calculating eGFR in daily clinical practice.

Pathological and Clinical Outcomes in a Large Surveillance and Intervention Cohort of Radiographically Cystic Renal Masses.

PURPOSE: We evaluated oncologic risks in a large cohort of patients with radiographic cystic renal masses who underwent active surveillance or intervention. MATERIALS AND METHODS: A single-institutional database of 4,340 kidney lesions managed with either active surveillance or intervention between 2000-2020 was queried for radiographically cystic renal masses. Association of radiographic tumor characteristics and high-grade pathology was evaluated. RESULTS: We identified 387 radiographically confirmed cystic lesions in 367 patients. Of these, 247 were resected (n=240) or ablated (n=7; n=247, 203 immediate vs 44 delayed intervention). Pathologically, 23% (n=56) demonstrated high-grade pathology. Cystic features were explicitly described by pathology in only 18% (n=33) of all lesions and in 7% (n=4) of high-grade lesions. Of the intervention cohort, African American race, male gender, and Bosniak score were associated with high-grade pathology (P < .05). On active surveillance (n=184), Bosniak IV lesions demonstrated faster growth rates than IIF and III lesions (2.7 vs 0.6 and 0.5 mm/y, P ≤ .001); however, growth rates were not associated with high-grade pathology (P = .5). No difference in cancer-specific survival was identified when comparing intervention vs active surveillance at 5 years (99% vs 100%, P = .2). No difference in recurrence was observed between immediate intervention vs delayed intervention (P > .9). CONCLUSIONS: A disconnect between "cystic" designation on imaging and pathology exists for renal lesions. Over 80% of radiographic Bosniak cystic lesions are not described as "cystic" on pathology reports. More than 1 in 5 resected cystic renal lesions demonstrated high-grade disease. Despite this finding, judiciously managed active surveillance ± delayed intervention is a safe and effective management option for most radiographic cystic renal masses.

Spontaneously ruptured multilocular cystic nephroma in an infant.

We present the case of a 10-month-old girl with spontaneously ruptured cystic nephroma with a 1-week-old abdominal mass and a 1-day history of marked abdominal distension. The tumor presented as gourd-shaped, cystic solid mass in the right kidney with fluid collection. The tumor was successfully removed by urgent surgery. The girl remained in good condition throughout six-month follow-up after.

Volumetric Quantitative Contrast-enhanced Ultrasonography Evaluation of Complex Renal Cysts: An Adjunctive Metric to the Bosniak Classification System to Predict Malignancy.

BACKGROUND: Management of complex renal cysts is guided by the Bosniak classification system, which may be inadequate for risk stratification of patients for intervention. Fractional tumor vascularity (FV) calculated from volumetric contrast-enhanced ultrasound (CEUS) images may provide additional useful information. OBJECTIVE: To evaluate CEUS and FV calculation for risk stratification of patients with complex renal cysts. DESIGN, SETTING, AND PARTICIPANTS: This was a pilot prospective study with institutional review board approval involving patients undergoing surgery for Bosniak IIF-IV complex renal cysts. CEUS was performed preoperatively on the day of surgery with two-dimensional (2D) and three-dimensional (3D) imaging and sulfur hexafluoride lipid-type A microspheres as the ultrasound contrast agent. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: A custom MATLAB program was used to select regions of interest on CEUS scans. FV was calculated according to FV = 1 - (total nonenhancing area/total lesion area). We assessed the ability of 2D- and 3D-derived percentage FV (2DFV%, and 3DFV%) and Bosniak classification schemes (pre-2019 [P2019B] and post-2019 [B2019]) to predict malignancy, aggressive histology, and upstaging on surgical pathology. Performance was assessed as area under the receiver operating characteristic curve (AUC). RESULTS AND LIMITATIONS: Twenty eligible patients were included in final analysis, of whom 85% (n = 17) had Bosniak IV cysts and 85% (n = 17) had malignant disease on final pathology. Four (24%) of the malignant lesions were International Society of Urological Pathology grade 3-4. The AUC for predicting malignancy was 0.980, 0.824, 0.863, and 0.824 with P2019B, B2019, 2DFV%, and 3DFV%, respectively. When the Bosniak classification was combined with FV%, three models had an AUC of 1, while the combined 2DFV% + B2019 model had AUC of 0.980. CONCLUSIONS: FV is a novel metric for evaluating complex cystic renal masses and enhances the ability of the Bosniak classification system to predict malignancy. This metric may serve as an adjunct in risk stratification for surgical intervention. Further prospective evaluation is warranted. PATIENT SUMMARY: Cysts in the kidney are currently classified using a scheme called the Bosniak system. We assessed measurement of the percentage of vascular tissue (called fractional vascularity) in cysts on a special type of ultrasound scan. This promising test adds information when combined with the Bosniak system and can help in guiding appropriate treatment.

Genotype and phenotype analysis and transplantation strategy in children with kidney failure caused by NPHP.

BACKGROUND: Nephronophthisis-related ciliopathies (NPHP-RC) have strong genotype and phenotype heterogeneity, and the transplantation strategy of Boichis syndrome is still controversial. Our purpose was to examine associations of genotype and phenotype in children with NPHP-RC and analyze the transplantation strategies of different phenotypes. METHODS: The records of children with NPHP treated at our center from 01/2018 to 03/2021 were retrospectively reviewed. Inclusion criteria were a diagnosis of NPHP, received kidney transplantation, and received whole exome sequencing (WES) or nephropathy gene panel testing. RESULTS: Twenty-nine children with NPHP were included. Nine children (31%) had NPHP1 mutations, and all presented with isolated nephropathy. Eighteen of 20 patients with non-NPHP1 mutations had compound heterozygous mutations, and 70% had extrarenal phenotype. Age at disease presentation (11.2 ± 1.94 years) and the development of kidney failure (12.4 ± 2.70 years) were later in children with NPHP1 mutations than those with non-NPHP1 mutations (5.2 ± 2.83 years and 5.7 ± 2.92 years, respectively). Four of six children with NPHP3 mutations were diagnosed with Boichis syndrome due to liver fibrosis. Isolated kidney transplantation resulted in good outcomes for patients with mild or moderate liver fibrosis without portal hypertension, while cholestasis was common postoperatively and could be resolved with ursodeoxycholic acid. CONCLUSIONS: NPHP1 mutations are the most common in children with NPHP, and the phenotype of NPHP1 mutation is significantly different from that of non-NPHP1 mutation. For NPHP patients with mild to moderate liver fibrosis without portal hypertension, timely treatment of cholestasis could prevent the rapid progression of liver function damage after isolated kidney transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Renal Cyst after Heminephrectomy in a Pediatric Patient: Complication or Normality?

INTRODUCTION: In this work, we present two cases of heminephrectomies with postoperative findings of cystic lesions in the bed of the excised renal segment. MATERIAL AND METHODS: Description of the clinical cases, therapeutic management and description of the ultrasound findings. A review of the published cases was carried out. RESULTS: We present a case of open heminephrectomy due to atrophy of the upper hemirrenal in a case of ureterocele, and another case with bilateral lower heminephrectomy in a case of vesicoureteral reflux disease. In the first case, the cystic lesion disappeared during follow-up, while in the second, the cysts remained stable. In none of the cases published in the literature was it necessary to perform any intervention to resolve the cysts. CONCLUSIONS: The appearance of cystic lesions in the heminephrectomy bed in pediatric patients is a radiological finding that occurs frequently. Due to its favorable evolution, without the need for additional procedures for its resolution, we do not consider the presence of these lesions as a complication after heminephrectomy.

Implication of cystic fluid cytology of renal cell carcinoma on surgical practice.

OBJECTIVES: To evaluate the incidence of positive cystic fluid cytology and its risk factors in cystic renal cell carcinoma (RCC) addressing its implication on the current surgical practice. METHODS: All clinically diagnosed Bosniak III, IV cystic renal masses from March 2019 to August 2022 were studied prospectively. Database of patients' demographics and cystic tumor characteristics were recorded. Partial or radical nephrectomies were performed by either laparoscopic or robotic approach. Cystic fluid was collected right after specimen retrieval in the surgical field and examined by pathologist. Cytology results were compared to the demographic, perioperative variables using univariate and multivariate analysis. RESULTS: A total of 70 patients of histologically confirmed cystic RCC were included. Sixty seven patients underwent radical nephrectomy with laparoscopic or robotic approaches, while 3 patients underwent radical nephrectomy. There was no intraoperative cystic rupture or fluid spillage. Positive cystic fluid cytology findings were identified in 34 (48.6%) patients, while negative cystic fluid cytology were identified in 36 (51.4%) cases. Definite malignant cells were observed in 28 patients while the other six patients showed highly suspicious atypical cells. Histologically, 24 (70.8%) patients were proven clear cell RCC and 25 (73%) showed Fuhrman grade 1 or 2 in final histologic review in positive group. Univariate and multivariate regression analysis between positive and negative cytology groups showed that the presence of the malignant cells in cystic fluid was significantly associated with patients' age (> 55 years) and Bosniak grade of cystic tumor (p < 0.05). CONCLUSIONS: Definite malignant cells in cystic fluid cytology were observed through our study. Additionally, patients' age (> 55 years) and Bosniak grade were the significant risk factors of positive cytology in cystic RCC. Therefore, necessity of meticulous manipulation of cystic renal tumors, despite their clinical features, should not be underemphasized to avoid the least possible tumor cell seeding in case of cystic rupture when operating such high risk of positive cytology.

Isolated giant renal hydatid cyst with a simple renal cyst appearance: a case report.

BACKGROUND: Isolated renal hydatid cysts of the kidney are a rare occurrence that account for about 2-3% of all hydatidoses. They can stay asymptomatic for years and could have a variable presentation on imaging techniques, which results in a challenging diagnostic process. CASE PRESENTATION: We report a 22-year-old Caucasian male with a large cyst on the upper pole of the left kidney that had no septations nor membrane calcifications on computed tomography, which led to mistakenly considering it a simple renal cyst. The true diagnosis was identified intraoperatively and proven postoperatively by pathology. CONCLUSIONS: This case highlights the importance of keeping echinococcosis in mind when treating suspected renal cysts and tumors to avoid incorrect treatment and possible content spillage, anaphylaxis, and peritoneal dissemination.

Robotic partial nephrectomy for complex kidney cyst in a 4-year old boy: Points of technique.

Complex kidney cysts are rarely observed in childhood. In adult patients, when radiological studies found a suspicious renal lesion, the gold standard is surgical asportation. The robotic surgery is well known as a secure procedure for treatment these patients, and is nowadays a real alternative also for pediatric patients. The challenges in children surgery are linked to anesthesiologic gestion, smaller operative fields, the need of specific instruments and more delicate tissue handling. We present a step-by-step video description of a robotic partial nephrectomy for a renal multicystic mass in a 4 year-old child.

[Features of surgical treatment of renal cysts depending on the risk of malignancy].

BACKGROUND: According to national and foreign publications, renal cyst is one of the most common urological diseases with a prevalence up to 20-50%. AIM: To determine the results of surgical treatment of patients with renal cysts, depending on the risk of malignancy. MATERIALS AND METHODS: The analysis of 124 patients with symptomatic renal cysts who were treated in the Department of Urology of Regional Clinical Hospital was carried out. All patients underwent a comprehensive clinical and instrumental evaluation, including contrast-enhanced CT scan of the kidneys. To assess the risk of harboring malignant tumor, the classification of renal cysts of Bosniak (2019) was used. RESULTS: The average age of patients was 56.6+/-12 years. According to CT, Bosniak I, II, IIF and III cysts were diagnosed in 96 (77.4%), 11 (8.9%), 11 (8.9%) and 6 (4.8%) patients, respectively. The morphologic study revealed renal cell cancer in 8 patients (6.4%), four of whom had Bosniak III cysts and other four had Bosniak IIF cysts. DISCUSSION: The prediction of the harboring of malignancy is a fundamental criterion for selection of patients with renal cysts for surgical treatment. CONCLUSION: Surgical treatment of symptomatic renal cysts is a justified treatment method, and in patients with Bosniak class II or higher cysts, it is necessary to exclude the malignant lesion. Based on our data, category IIF and III cysts have a high risk of harboring malignant cells, which is 36.4% and 66.7%, respectively. In our opinion, laparoscopic partial nephrectomy is the most rational treatment method in these categories.

Clinical efficacy of intraoperative real time ultrasound-assisted flexible ureteroscopic holmium laser incision and internal drainage in the treatment of parapelvic cysts.

OBJECTIVE: This study aims to investigate the efficacy and safety of intraoperative real time ultrasound-assisted flexible ureteroscopic holmium laser incision and internal drainage in the treatment of parapelvic cysts, and to review recently published relevant literature. METHOD: This is a retrospective study in which the clinical data of 47 patients who underwent flexible ureteroscopic holmium laser incision and internal drainage of parapelvic cysts in our center from March 2017 to March 2021 were retrospectively analyzed. A literature search was conducted to review and summarize relevant reports on endoscopic treatment of parapelvic cysts published in the past 10 years. RESULTS: Among 47 patients with parapelvic cysts who underwent flexible ureteroscopic holmium laser incision and internal drainage, 12 (25.53%) cases had a typical cyst wall bulging into the collecting system under flexible ureteroscope. As the cyst wall was thin and translucent in these cases, ultrasound was not used during the operation. The cysts of the remaining 35 patients were located with the aid of intraoperative real time ultrasound, and all underwent successful operation. No serious surgical complications occurred after surgery. The patients were followed up for 12-24 months after operation. The cyst in one case was observed larger than its original size before operation, so recurrence was considered. In another two cases, the diameters of the cysts were more than half of their original diameters before operation. Thus, the efficacy was poor in the three cases. For the remaining 44 cases, there was no obvious cyst observed or the diameter of the cysts was less than half their preoperative level. CONCLUSION: The approach of ultrasound-assisted flexible ureteroscopic holmium laser incision and internal drainage in the treatment of parapelvic cysts is safe and effective, which helps to solve the problem of localization of atypical parapelvic cysts on endoscopic findings.

Transurethral flexible ureteroscopic incision and drainage with holmium laser in the treatment of parapelvic renal cysts: A retrospective study.

BACKGROUND: We aimed to investigate the clinical efficacy and safety of transurethral flexible ureteroscopic incision and drainage with holmium laser in the treatment of parapelvic renal cysts. MATERIALS AND METHODS: Between October 2017 and April 2021, the clinical data of 65 patients with parapelvic renal cysts were evaluated retrospectively. Thirty-one patients with parapelvic cysts (Group 1) underwent a transurethral flexible ureteroscopic incision and drainage with a holmium laser, whereas the other 34 patients (Group 2) underwent retroperitoneal laparoscopic unroofing. The patients' clinical features were documented. The surgery time, intraoperative blood loss, hospitalization time, complications and cyst size were recorded and statistically assessed one year following the procedure. RESULTS: All of the patients were successfully treated with flexible ureteroscopic incision and drainage or retroperitoneal laparoscopic unroofing. In terms of clinical parameters, such as age, gender, BMI, location, cyst size, and Bosniak classification of renal cysts, no statistically significant difference was detected between Groups 1 and 2. Compared to the control group (Group 2), Group 1 demonstrated a shorter surgery duration, less intraoperative blood loss, and a shorter hospital stay (p < 0.001). However, no significant differences in complications and cyst size were observed between the two groups one year after the surgery (p > 0.05). CONCLUSIONS: Transurethral flexible ureteroscopic incision and drainage with holmium laser in the treatment of parapelvic renal cysts has obvious advantages over traditional surgery, and is worthy of advancement and application, but its long-term effect needs further follow-up studies.

Active surveillance versus initial surgery in the long-term management of Bosniak IIF-IV cystic renal masses.

There may be surgical overtreatment of complex cystic renal masses (CRM). Growing evidence supports active surveillance (AS) for the management for Bosniak IIF-III CRMs. We aimed to evaluate and compare oncological and pathological outcomes of Bosniak IIF-IV CRMs treated by initial surgery (IS) or AS. We identified retrospectively 532 patients with CRM counseled during 2006-2017. IS and AS were delivered to, respectively, 1 and 286 patients in Bosniak IIF, to 54 and 85 patients in III and to 85 and 21 patients in Bosniak IV. Median follow-up was 66 months (IQR 50-96). Metastatic progression occurred for 1 (0.3%) AS patient in Bosniak IIF, 1 IS (1.8%) and 1 AS (1.2%) patient in Bosniak III and 5 IS (3.5%) patients in Bosniak IV, respectively. Overall 5-year metastasis-free survival was 98.9% and cancer-specific survival was 99.6% without statistically significant difference between IS and AS in Bosniak IIF-IV categories. AS did not increase the risk of metastatic spread or cancer-specific mortality in patients with Bosniak IIF-IV. Our data indicate AS in Bosniak IIF and III is safe. Surgery is the primary treatment for Bosniak IV due to its high malignancy rate.

Giant renal parapelvic cyst with pelvi-ureteric junction obstruction in an infant: challenges in diagnosis and laparoscopic management.

Renal parapelvic cysts (RPC) have an incidence of approximately 1%-3% in the general population. However, they rarely present in children with only two cases reported in literature. RPC are often misdiagnosed as it is difficult to distinguish them from hydronephrosis on preoperative imaging. We report a case of an infant with a giant RPC with associated pelvi-ureteric junction obstruction, who was managed successfully with laparoscopic complete excision of RPC and dismembered pyeloplasty. In our report, we discuss the challenges faced in the diagnosis and surgical management of this unusual case.

Use of intraoperative impression smear cytology to guide successful treatment of a large renal cyst in a dog: a case report.

A 13-yr-old Shih tzu was referred for surgical management of right-sided cranial abdominal mass, which corresponded to large, cavitated renal mass on ultrasonography, and was suspected to represent neoplasia. Intraoperative impression smear cytology (ISC) of the renal mass wall was consistent with benign renal cyst (RC), without evidence of neoplasia or infection. Deroofing and omentalisation were performed and histopathology was consistent with benign RC. Chronic kidney disease was diagnosed 4 mon postoperatively, however, the dog was asymptomatic, without cyst reoccurrence. Intraoperative ISC is an expedient and inexpensive diagnostic technique that can guide most appropriate treatment in dogs with large RCs.

[Endoscopic marsupialization of parapelvic renal cysts].

INTRODUCTION: Parapelvic renal cysts are very common. Indications for surgical treatment are upper urine tract obstruction, pain and recurrent gross hematuria. AIM: To analyze the efficiency and safety of endoscopic transurethral and percutaneous laser marsupialization of parapelvic renal cysts. MATERIALS AND METHODS: A total of 9 patients were undergone to transurethral intrarenal marsupialization of parapelvic renal cysts from March 2016 to February 2021 (4 men, 5 women, aged 42-78 years). Another 2 patients (2 men, aged 46 and 52 years) were treated by percutaneous approach. The average size of the cyst according to contrast-enhanced multi-slice computed tomography (MSCT) was 3.1+/-1.8 cm. In two cases, papillary tumor of the pelvis was suspected. The anteroposterior diameter of the pelvis was 2.6+/-1.3 cm; 9 patients had pain in the loin area, while in 7 patients recurrent gross hematuria was also an indication for surgical treatment. For marsupialization, a holmium (Ho:YAG) laser Auriga XL (Boston Scientific, USA) was used in 4 patients, and in other cases (n=7) a procedure was performed using a thulium fiber laser (Tm Fiber) Fiberlase U1 (IRE-Polus, Russia). In 3 patients, to clarify the site of incision of the cyst, intraoperative ultrasound was used. In all cases, after draining the cyst, an internal stent was placed inside the cyst for a period of 4-6 weeks. RESULTS: The duration of transurethral surgery was 26+/-11 minutes, while percutaneous marsupialization of the cyst, which was performed in combination with percutaneous nephrolithotomy, took 10 and 18 minutes, respectively. The average catheterization time was 12+/-8 hours. Nephrostomy tube was removed on the 2nd day. The length of stay was 4+/-2 days. Febrile fever was noted in 1 patient (9%), which required a change in antibiotic therapy. During ultrasound control at discharge, the dilatation of the collecting system was not detected in any cases, while the residual cavity was found in 2 patients (18%). Follow-up contrast-enhanced MSCT and ultrasound within 3-30 months in all patients (n=11) showed no dilatation of the collecting system. In 1 (9%) patient, the residual cavity was preserved with a decrease in size to 1.2 cm without signs of upper urinary tract obstruction; the initial diameter of the cyst in this patient was 4.9 cm. There was no recurrence of gross hematuria. CONCLUSIONS: In our opinion, transurethral and percutaneous laser marsupialization of parapelvic renal cysts is an effective and safe method that allows definitive treatment for cysts up to 4 cm in size. If the cyst is larger than 4 cm, endoscopic removal should be balanced with the possibility of preserving the residual cavity. The most common complication of endoscopic treatment of intrarenal cysts is acute pyelonephritis with a rate of 9%.

Long-term follow-up of a juvenile simple renal cyst in a dog treated by laparoscopic deroofing, fulguration, and omentalization.

CASE DESCRIPTION: A 10-month-old male crossbred dog presented with a 4-week history of polyuria and polydipsia and a 6-month history of vomiting. CLINICAL FINDINGS: Clinical examination revealed abdominal pain and right-sided nephromegaly. Biochemistry was within normal limits. Diagnostic imaging showed a well-defined, unilateral renal mass containing anechoic fluid consistent with a simple renal cyst (SRC). TREATMENT AND OUTCOME: The cyst was drained under ultrasonographic guidance but recurred 3 months later, concomitant with recurrence of the previously reported clinical signs. The cyst was then deroofed, fulgurated, and omentalized under laparoscopy by use of a 3-port technique. The resected cystic wall was histopathologically consistent with an SRC, presumptively congenital. The dog showed a good recovery with resolution of clinical signs. Renal function was normal at last follow-up, conducted 2 years postoperatively, without evidence of recurrent disease. CLINICAL RELEVANCE: To our knowledge, this was the first report of a symptomatic juvenile SRC of presumptively congenital origin in a dog treated successfully by laparoscopic deroofing, fulguration, and omentalization. The polyuria, polydipsia, chronic vomiting, and abdominal pain may all have been related to space-occupying effects of the cyst, as these symptoms resolved post-treatment. Results of long-term follow-up advocate for this durable cure of SRC by use of laparoscopic procedures, especially when compared to simple drainage of the cyst, as the latter initially failed in the present case.