Cystic Renal Tumors Research Articles

Multilocular Cystic Renal Neoplasia of Low-grade Malignant Potential: Evolving Diagnostic Criteria: A Case Report with Review of Literature

Multilocular Cystic Renal Neoplasm of Low Malignant Potential (MCRNLMP) is a distinct type of clear cell renal tumor. The diagnostic histological criteria for this entity have evolved, and specific histological features have been modified over the years. The WHO 2022 of Male Urinary System and Male Genital Tumours respecified diagnostic histopathological features. Maximum tumors are asymptomatic and are incidentally detected on radiological examination. Computed tomography using contrast agents is still the gold standard for classifying cystic tumors of kidney. The Bosniak category of renal cystic lesions is crucial for the management of other imaging modalities such as magnetic resonance imaging (MRI) and contrast-enhanced ultrasound, which can be used with the same effectiveness. The prognosis is excellent in MCRNLMP, and there are no reports of cancer progression or metastasis. Minimally invasive nephron-sparing surgery with strict clinical including imaging follow-up with contrast-enhanced computerized tomography and magnetic resonance imaging is a choice of treatment.

PE065 Perioperative and oncological outcomes of robotic partial nephrectomy for cystic and solid renal tumors with the new Hugo™ RAS System: A single surgeon comparative analysis

PE065 Perioperative and oncological outcomes of robotic partial nephrectomy for cystic and solid renal tumors with the new Hugo™ RAS System: A single surgeon comparative analysis

VE55 Surgical outcomes of HugoTM RAS partial nephrectomy for cystic renal tumor

VE55 Surgical outcomes of HugoTM RAS partial nephrectomy for cystic renal tumor

Multilocular cystic renal neoplasm: a rare tumor in kidney

Multilocular cystic renal cell carcinoma is a rare cystic tumour of kidney with excellent outcome. It is usually included in the group of tumours of undetermined malignant potential with low nuclear grade. We are presenting a case of 61 year. old female came with history of giddiness for 1 week and weight loss of 20 kg in 2 years. Imaging was suggestive of cortical based tumour arising from upper pole of right kidney. Right side partial nephrectomy was done. On histopathologic examination it was found to be MCRCC, stage 1 with Fuhrman nuclear grade 1. Immunohistochemistry with epithelial membrane antigen and cytokeratin-7 confirmed the diagnosis.

Surgical Outcomes of Hugo™ RAS Robot-Assisted Partial Nephrectomy for Cystic Renal Masses: Technique and Initial Experience.

Background: The Hugo™ Robot-Assisted Surgery (RAS) system is a new cutting-edge robotic platform designed for clinical applications. Nevertheless, its application for cystic renal tumors has not yet been thoroughly investigated. In this context, we present an initial series of Robot-Assisted Partial Nephrectomy (RAPN) procedures carried out using the Hugo™ RAS system for cystic renal masses. Methods: Between October 2022 and January 2024, twenty-seven RAPN procedures for renal tumors were performed at Fondazione Policlinico Universitario Campus Bio-Medico. Our prospective board-approved dataset was queried for "cystic features" (n = 12). Perioperative data were collected. The eGFR was calculated according to the CKD-EPI formula. Post-operative complications were reported according to the Clavien-Dindo classification. Computed tomography (CT) scans for follow-up were performed according to the EAU guidelines. Trifecta was defined as the coexistence of negative surgical margin status, no Clavien-Dindo grade ≥ 3 complications, and eGFR decline ≤ 30%. Results: All the patients successfully underwent RAPN without the need for conversion or additional port placement. The median docking and console time were 5.5 (IQR, 4-6) and 79.5 min (IQR, 58-91 min), respectively. No intraoperative complications occurred, as well as clashes between instruments or with the bedside assistant. Two minor postoperative complications were recorded (Clavien-Dindo II). At discharge, serum creatinine and eGFR were comparable to preoperative values. Only one patient (8.4%) displayed positive surgical margins. The rate of trifecta achievement was 91.7%. Conclusions: RAPN for cystic renal masses using the novel Hugo™ RAS system can be safely and effectively performed. This robotic system provided satisfactory peri-operative outcomes, preserving renal function and displaying low postoperative complications and a high trifecta rate achievement.

Laparoscopic nephron-sparing surgery for complex renal cystic lesions: a single-center experience.

This study aimed to explore the feasibility and safety of laparoscopic nephron-sparing surgery (LNSS) for complex renal cystic lesions. A retrospective study was conducted on 83 cases of complex renal cystic lesions treated with LNSS in our hospital. There were 32 men and 51 women, ranging in age from 24 to 73years (average, 47.22±9.03years). The diameter of the cysts was 1.5-5.9cm (average, 3.44±0.86cm). According to the Bosniak classification, there were 15 cases of type II, 23 cases of type IIF, 29 cases of type III, and 16 cases of type IV complex renal cystic lesions. According to clinical classification based on the difficulty of laparoscopic partial nephrectomy and the depth of the lesion, the 83 complex renal cystic lesions were divided into 48 cases of the extra-renal type, 15 cases of the centrally located type, seven cases of the renal sinus type, and 13 cases of the renal hilum type. Laparoscopic partial nephrectomy was successful in all 83 patients. The surgical time was 35-102min (average, 52.13±14.38min), the intraoperative bleeding volume was 10-200ml (average, 27.25±12.26ml), and the renal artery occlusion time was 12-28min (average, 12.46±4.45min). There was no significant change in creatinine before and after surgery. The postoperative pathological results showed 71 cases of renal clear cell carcinoma, five cases of low malignant potential multilocular cystic renal tumors, and seven cases of pure renal cysts with all margins negative. There is potential for the malignant transformation of complex renal cysts into renal cell carcinoma. For complex renal cysts classified as Bosniak IIF or higher, surgical intervention is recommended, and LNSS is safe and effective. The complexity of the surgical procedure varies depending on the location classification of the complex renal cysts.

Long-Term Oncologic Outcomes of Off-Clamp Robotic Partial Nephrectomy for Cystic Renal Tumors: A Propensity Score Matched-Pair Comparison of Cystic versus Pure Clear Cell Carcinoma.

Few data are available on survival outcomes of partial nephrectomy performed for cystic renal tumors. We present the first long-term oncological outcomes of cystic (cystRCC) versus pure clear cell renal cell carcinoma (ccRCC) in a propensity score-matched (PSM) analysis. Our "renal cancer" prospectively maintained database was queried for "cystRCC" or "ccRCC" and "off-clamp robotic partial nephrectomy" (off-C RPN). The two groups were compared for age, gender, tumor size, pT stage, and Fuhrman grade. A 1:3 PSM analysis was applied to reduce covariate imbalance to <10% and two homogeneous populations were generated. Student t- and Chi-square tests were used for continuous and categorical variables, respectively. Ten-year oncological outcomes were compared between the two cohorts using log-rank test. Univariable Cox regression analysis was used to identify predictors of disease progression after RPN. Out of 859 off-C RPNs included, 85 cases were cystRCC and 774 were ccRCC at histologic evaluation. After applying the PSM analysis, two cohorts were selected, including 64 cystRCC and 170 ccRCC. Comparable 10-year cancer-specific survival probability (95.3% versus 100%, p = 0.146) was found between the two cohorts. Conversely, 10-year disease-free survival probability (DFS) was less favorable for pure ccRCC than cystRCC (66.69% versus 90.1%, p = 0.035). At univariable regression analysis, ccRCC histology was the only independent predictor of DFS probability (HR 2.96 95% CI 1.03-8.47, p = 0.044). At the 10-year evaluation, cystRCC showed favorable oncological outcomes after off-C RPN. Pure clear cell variant histology displayed a higher rate of disease recurrence than cystic lesions.

Clinicopathological characteristics and typing of multilocular cystic renal neoplasm of low malignant potential.

Up until now, no research has been reported on the association between the clinical growth rate of multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) and computed tomography (CT) imaging characteristics. Our study sought to examine the correlation between them, with the objective of distinguishing unique features of MCRNLMP from renal cysts and exploring effective management strategies. To investigate optimal management strategies of MCRNLMP. We retrospectively collected and analyzed data from 1520 patients, comprising 1444 with renal cysts and 76 with MCRNLMP, who underwent renal cyst decompression, radical nephrectomy, or nephron-sparing surgery for renal cystic disease between January 2013 and December 2021 at our institution. Detection of MCRNLMP utilized the Bosniak classification for imaging and the 2016 World Health Organization criteria for clinical pathology. Our meticulous exploration has revealed compelling findings on the occurrence of MCRNLMP. Precisely, it comprises 1.48% of all cases involving simple renal cysts, 5.26% of those with complex renal cysts, and a noteworthy 12.11% of renal tumors coexisting with renal cysts, indicating a statistically significant difference (P = 0.001). Moreover, MCRNLMP constituted a significant 22.37% of the patient population whose cysts demonstrated a rapid growth rate of ≥ 2.0 cm/year, whereas it only represented 0.66% among those with a growth rate below 2.0 cm/year. Of the 76 MCRNLMP cases studied, none of the nine patients who underwent subsequent nephron-sparing surgery or radical nephrectomy following renal cyst decompression experienced recurrence or metastasis. In the remaining 67 patients, who were actively monitored over a 3-year postoperative period, only one showed suspicious recurrence on CT scans. MCRNLMP can be tentatively identified and categorized into three types based on CT scanning and growth rate indicators. In treating MCRNLMP, partial nephrectomy is preferred, while radical nephrectomy should be minimized. After surgery, active monitoring is advisable to prevent unnecessary nephrectomy.

The Predictive Power of Bosniak 3 and 4 Cystic Renal Lesion Categorization Using Contrast-Enhanced Ultrasound.

Contrast-enhanced ultrasound (CEUS) is increasingly utilized for the noninvasive assessment of renal cystic lesions, using the Bosniak grading system. Bosniak 3-4 lesions require surgical referral, which allows correlation with the histopathological outcome. In this single-center, retrospective study we evaluated renal CEUS exams conducted with SonoVue® with a diagnosis of a Bosniak 3 or 4 lesion between 2019 and 2022. A total of 49 patients and 50 lesions met the inclusion criteria, 31 lesions had available histopathological results. Patient demographics, cyst morphology, and dominant imaging features were registered. The histopathological diagnosis was considered a reference standard. Positive predictive power (PPV) for neoplastic lesions was comparable in the Bosniak 3 and 4 categories (75 vs 93.3%, P = .33), while PPV for histopathologically malignant lesion was considerably higher in the latter group (25 vs 93.33%, P = .0002). None of the lesions which had vividly enhancing thin septa as their dominant CEUS feature were malignant. Oncocytoma, multilocular cystic renal neoplasm of low malignant potential, and cystic nephroma were the major benign entities among Bosniak 3 lesions. Localized cystic kidney disease and hemorrhagic cysts were found to be the primary mimickers leading to false positive imaging findings. CEUS has a high predictive power for malignancy in the Bosniak 4 category, which is not maintained in the Bosniak 3 group due to the large proportion of benign lesions. Adherence to rigorous rule-in criteria and active surveillance strategies need to be considered for equivocal CEUS Bosniak 3 lesions.

Renal cystic masses management: Literature review

This review article aims to cover the anatomical and pathological characteristics of cystic renal tumors as well as their treatment. The reason behind delving into this topic is due to an increase in diagnoses of renal cysts, which necessitates knowledge on how to correctly identify and handle potentially malignant lesions. Renal cysts are classified using the Bosniak system by medical professionals worldwide to determine their potential for malignancy. The likelihood of cancerous cells increases from 0% in category I, up to 95% in category IV. Renal cell carcinoma is the most common pathology observed and usually presents with a low grade and stage. Cysts categorised as IIF (indicating follow-up) have a chance of malignancy at around 25%, which necessitates monitoring every six months for five years after detection via imaging such as CT scans, MRI or contrast-enhanced ultrasonography. Although biopsy was formerly not recommended, it can now prevent roughly forty percent of unnecessary surgeries required while treating benign growths. Symptomatic treatments like sclerotherapy or laparoscopic deroofing may be applied if dealing with categories I through II cysts; however, lesion types categorized under III &amp; IV should receive treatment akin to malignant tumours requiring margins that ensure safety during interventions conducted on them.

Optimizing the kidney donor pool: transplanting donor kidneys after partial nephrectomy of masses or cysts.

A limiting factor in expanding the kidney donor pool is donor kidneys with renal tumors or cysts. Partial nephrectomy (PN) to remove these lesions prior to transplantation may help optimize organ usage without recurrence of malignancy or increased risk of complications. We retrospectively analyzed all recipients of a living or deceased donor graft between February 2009 and October 2022 in which a PN was performed prior to transplant due to the presence of one or more concerning growths. Donor and recipient demographics, perioperative data, donor allograft pathology, and recipient outcomes were obtained. Thirty-six recipients received a graft in which a PN was performed to remove suspicious masses or cysts prior to transplant. Majority of pathologies turned out to be a simple renal cyst (65%), followed by renal cell carcinoma (15%), benign multilocular cystic renal neoplasm (7.5%), angiomyolipoma (5%), benign renal tissue (5%), and papillary adenoma (2.5%). No renal malignancy recurrences were observed during the study period (median follow-up: 67.2 months). Fourteen complications occurred among 11 patients (30.6% overall) during the first 6mo post-transplant. Mean eGFR (± standard error) at 36 months post-transplant was 51.9 ± 4.2 ml/min/1.73 m2 (N = 23). Three death-censored graft losses and four deaths with a functioning graft and were observed. PN of renal grafts with suspicious looking masses or cysts is a safe option to optimize organ usage and decrease the kidney non-use rate, with no observed recurrence of malignancy or increased risk of complications.

Cystic Features in Renal Epithelial Neoplasms and Their Increasing Clinical and Pathologic Significance.

Most cystic renal tumors after resection (Boniak IIF to IV cysts) have an indolent course despite the significantly higher proportion of malignant [ie, renal cell carcinoma (RCC)] diagnosis. Most cystic renal tumors have clear cell histology that include cystic clear cell RCC and multilocular cystic renal neoplasm of low malignant potential (MCNLMP). There is growing evidence to suggest that MCNLMP, cystic clear cell RCC, and noncystic clear cell RCC form a cystic-to-solid biological spectrum with MCNLMP representing the most indolent form and with cystic clear cell RCC behaving better than noncystic (solid) clear cell RCC. Extensively (>75%) cystic clear cell RCC also has an excellent outcome similar to MCNLMP stressing the need to reevaluate the histologic criteria that separate these 2 cystic clear cell tumors. Other tumors with clear cells that can be extensively cystic such as the recently reclassified noncancerous clear cell papillary renal tumor and the newly described MED15::TFE3 RCC also have indolent course and may mimic MCNLMP. Cystic features occur also in renal tumors with nonclear cell histology including tumors capable of metastasis such as acquired cystic disease-associated, tubulocystic, fumarate hydratase-deficient, and eosinophilic solid and cystic RCCs. Cystic imaging presentation of some renal tumors such as papillary RCC can be attributed in part to pseudocystic necrosis and hemorrhage. It is important to know that tubulocystic RCC may have a lower Bosniak class presentation that overlaps with benign renal cysts (Bosniak I to IIF) that are managed conservatively. This review highlights the cystic renal tumors with clear cell and nonclear cell morphologies including some novel RCC subtypes that may have cystic features. The presence of cystic features and their extent may aid in the classification and prognostication of renal neoplasms underscoring its increasing importance in the pathologic diagnosis and reporting of renal neoplasia.

Смешанная эпителиальная и стромальная опухоль в сочетании с онкоцитомой почки: редкий клинический случай и обзор литературы.

Introduction. Mixed epithelial and stromal tumors (MEST) of the kidney are rare neoplasms and, along with adult cystic nephroma, are grouped together called mixed epithelial and stromal tumors (World Health Organization Classification of Tumors of the Kidney, 2022). Clinically and radiologically, they mimic other cystic renal neoplasms, thus definitive diagnosis requires histological and immunohistochemical examination. Despite the benign course, MEST can undergo malignancy; isolated cases of recurrence have also been documented. Clinical case. Patient X, 65 years old, underwent robot-assisted left-side partial nephrectomy for cystic formations of the left kidney with a hypervascular soft tissue component along the medial semicircle of one of the cysts. According to histological examination, MEST of the left kidney in combination with oncocytoma was diagnosed. Conclusions. This article presents probably the first published case of MEST in combination with oncocytoma of the kidney.

Alpha-methyl CoA racemase (AMACR) reactivity across the spectrum of clear cell renal cell neoplasms

a-Methylacyl coenzyme A racemase (AMACR) is traditionally considered to be a marker of papillary renal cell carcinoma. However, AMACR expression can be seen in other renal tumors. The aim of this study was to investigate AMACR immunoreactivity within the spectrum of clear cell renal cell neoplasms.Fifty-three clear cell renal epithelial tumors were used in assembling the following four cohorts: low grade (LG) clear cell renal cell carcinoma (CCRCC), high grade (HG) CCRCC, CCRCC with cystic changes, and multilocular cystic renal neoplasm of low malignant potential (MCRNLMP). Representative blocks were stained for AMACR, using two different clones (SP52 and OV-TL12/30).There were at least some AMACR immunoreactivity in 77.8 % and 68.9 % of CCRCCs (using SP52 and OV-TL12/30 clone, respectively). Moderate to strong positivity, or positivity in more than one third of the tumor (even weak in intensity) was detected in 46.7 % of CCRCCs using SP52 and in 48.9 % of CCRCC using OV-TL12/30 clone. The highest AMACR reactivity was observed in HG CCRCC (60 % by SP52 and 66.7 % by OV-TL12/30). Strong and diffuse AMACR positivity was detected in 8.9 % of all CCRCCs. AMACR immunoreactivity in MCRNLMP was 37.5 % (SP52 clone) and 25 % (OV-TL12/30 clone).We demonstrated relatively high expression rate of AMACR in CCRCC, while very variable in intensity and distribution. This finding may have diagnostic implications especially in limited samples (i.e., core biopsies), as AMACR positivity does not exclude the diagnosis of CCRCC.

MED15::TFE3 fusion renal cell carcinoma with extensive cystic change: A clinicopathologic and molecular genetic study of 2 cases, with an emphasis on differential diagnosis.

TFE3-rearranged renal cell carcinomas (RCCs) harbor gene fusions between TFE3 and 1 of many partner genes. MED15::TFE3 fusion RCC is rare, often cystic, and easily misdiagnosed. This study aimed to characterize 2 cases of MED15::TFE3 fusion RCC with extensive cystic change using fluorescence in situ hybridization and targeted RNA sequencing. Both patients were young adult women aged 29 and 35 years. Radiologically, both presented with a cystic Bosniak category II renal lesion. The cysts measured 9.3 cm and 4.8 cm in greatest dimension. Both patients underwent cyst enucleation, and neither had tumor recurrence or metastasis at 26 and 6 months of follow-up, respectively. Microscopically, both tumors were entirely cystic, with thick, fibrous cystic walls lined by small clusters of cells with clear to eosinophilic cytoplasm and uniform, round nuclei with inconspicuous nucleoli. There were also small aggregations of similar clear cells within the cystic walls. Foci of basement membrane-like material depositions were noted in 1 case; calcifications were observed in both cases. Both cases demonstrated nuclear positivity for PAX8 and TFE3 and cytoplasmic staining for Melan-A; HMB45, CAIX, and CK7 were negative. Fluorescence in situ hybridization revealed that both tumors were positive for TFE3 rearrangements. RNA sequencing identified MED15::TFE3 gene fusions in both cases. The main differential diagnosis of MED15::TFE3 fusion RCC includes multilocular cystic renal neoplasm of low malignant potential and atypical renal cysts. Molecular confirmation of TFE3 fusion is essential for establishing the correct diagnosis.

Cystic partially differentiated nephroblastoma in an 18-month-old girl: a case report

Introduction and importance: Cystic partially differentiated nephroblastoma (CPDN) is a rare cystic tumor that affects the kidney. It has a low potential for malignancy. It usually presents as an abdominal mass. It may be difficult to confirm the diagnosis of CPDN without a histopathological study. Case presentation: The authors report a case of an 18-month-old girl with abdominal distention, which was noticed by her parents. An abdominal computed tomography scan showed a large multilocular cystic mass arising from the lower pole of the left kidney. A left total nephrectomy was performed. Immature blastemal elements without evidence of malignant cells were observed on histological analysis. Conclusion: The authors report a case of an 18-month-old girl with CPDN managed by total nephrectomy. CPDN should be considered in the differential diagnosis of patients with cystic renal lesions. The authors would also like to affirm that partial or total nephrectomy should be done in all cases of CPDN and other cystic renal tumors.

Multilocular Cystic Nephroma in Adult: About A Case Report and Review of the Literature

Background: Multicystic nephroma is a rare entity of cystic renal tumor, it is a benign non-hereditary pathology with an excellent prognosis, whose preoperative diagnosis is often difficult. Only the anatomopathological study can confirm this. Case Presentation: 54-year-old patient, having consulted for right low back pain evolving for 6 months without any other associated sign. The clinical examination objectified a slight tenderness of the right lumbar fossa. Abdominal ultrasound revealed a 6 cm multi-partitioned cystic renal mass. The uroscanner identified a right mid-renal cystic mass with multilocules containing fine and regular partitions, with exo-renal development measuring 66*74 mm classified Bosniak IIF. A resection of the entire cyst by lombotomy was performed, the histological examination of which came back in favor of a multicystic nephroma. Conclusion: The discovery of a cystic renal tumor often represents a source of uncertainty as to its potential for malignancy. The definitive diagnosis can only be made after surgical management with histological study.

VE71 - Surgical outcomes of Hugo RAS robot-assisted partial nephrectomy for cystic renal tumor

VE71 - Surgical outcomes of Hugo RAS robot-assisted partial nephrectomy for cystic renal tumor

Multilocular cystic renal neoplasm of low malignant potential in a patient with chronic pyelonephritis and end-stage renal disease: A rare case report

Multilocular cystic renal neoplasm of low malignant potential (MCNLMP) is a rare subtype of clear cell carcinoma having an excellent prognosis. These tumors exhibit distinct morphology and consist of multiple cysts separated by thin septa lined by clear cells with no expansile growth. These cysts, though rare in a setting of chronic pyelonephritis and end-stage renal disease, are usually diagnosed on radiography using the Bosniak classification. But in certain situations where cysts are not visible radiologically, a final diagnosis is made with the help of histopathology and immuno- histochemistry only. We, hereby, report such a rare incidental case of MCNLMP diagnosed on histopathology in a nephrectomy specimen of an elderly male with chronic pyelonephritis and end-stage renal disease.

Cystic Clear Cell Renal Cell Carcinoma: A Morphological and Molecular Reappraisal.

A wide variety of renal neoplasms can have cystic areas. These can occur for different reasons: some tumors have an intrinsic cystic architecture, while others exhibit pseudocystic degeneration of necrotic foci or they have cystically dilated renal tubules constrained by stromal neoplastic cells. Clear cell renal cell carcinoma (CCRCC), either solid or cystic, is the most frequent type of renal cancer. While pseudocysts are found in high-grade aggressive CCRCC, cystic growth is associated with low-grade indolent cases. The latter also form through a cyst-dependent molecular pathway, and they are more frequent in patients suffering from VHL disease. The differential diagnosis of multilocular cystic renal neoplasm of low malignant potential and clear cell papillary renal cell tumor can be especially hard and requires a focused macroscopical and microscopical pathological analysis. As every class of renal tumor includes cystic forms, knowledge of the criteria required for a differential diagnosis is mandatory.