CYSTIC RENAL CELL CARCINOMAS IN ADULTS. IS PREOPERATIVE RECOGNITION OF MULTILOCULAR CYSTIC RENAL CELL CARCINOMA POSSIBLE?

A Comprehensive Commentary on the Multilocular Cystic Renal Neoplasm of Low Malignant Potential: A Urologist’s Perspective

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) is a cystic renal tumor with indolent clinical behavior. In most of cases, it is an incidental finding during the examination of other health issues. The true incidence rate is estimated to be between 1.5% and 4% of all RCCs. These lesions are classified according to the Bosniak classification as Bosniak category III. There is a wide spectrum of diagnostic tools that can be utilized in the identification of this tumor, such as computed tomography (CT), magnetic resonance (MRI) or contrast-enhanced ultrasonography (CEUS). Management choices of these lesions range from conservative approaches, such as clinical follow-up, to surgery. Minimally invasive techniques (i.e., robotic surgery and laparoscopy) are preferred, with an emphasis on nephron sparing surgery, if clinically feasible.

Multilocular Cystic Renal Neoplasm of Low Malignant Potential: A Case Report and Literature Review

Multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) is a rare subtype of renal cell carcinoma that has a favorable outcome. Most cases of MCRNLMP usually present as distinct multilocular cystic lesions; however, they may appear as small complicated cysts with hemorrhagic components. Herein, we present a case of MCRNLMP and provide a review of the literature.

Update on MR Imaging of cystic retroperitoneal masses

OBJECTIVE

This article reviews the MRI appearance of cystic retroperitoneal (RP) masses.

CONCLUSION

Lymphangiomas are the most common RP cystic masses and typically appear simple; microscopic fat is a specific but insensitive finding. Location, internal complexity, and enhancement pattern suggest alternative diagnoses which range from normal anatomic variants to congenital abnormalities and importantly include benign, neurogenic, and malignant neoplasms. An approach to the MR imaging of cystic RP masses is presented.

Ultrasound Imaging of Cystic Nephroma

Cystic nephroma is a rare, benign multicystic lesion of the kidney. This tumor occurs both in children and in adults. In children, it is highly prevalent in males; in adults, it is more frequent in women. The term “cystic nephroma” represents two apparently different entities: pediatric cystic nephroma, a benign form thought to originate from metanephric tissue, and adult cystic nephroma, considered as a lesion of mixed epithelial stromal tumor. The clinical presentation may be a palpable mass or nonspecific symptoms such as abdominal pain, hematuria, and urinary tract infections. In this review, we summarize the ultrasound imaging features of cystic nephroma and describe the characteristics of the most common renal cystic lesions and the differential diagnosis of cystic nephroma with other renal cystic lesions.

Multilocular Cystic Renal Cell Carcinoma or Cystic Nephroma?

The incidence of Multilocular cystic renal cell carcinoma (MCRCC) in literature is very low and confounding MCRCC with cystic nephroma (CN) is even more unusual. The aim of this report is to present a case of MCRCC and emphasize the importance of the preoperative radiologic evaluation and immunohistochemical staining confirmation to obtain an accurate diagnosis. A 73-year-old woman presented with a history of 4-month right flank pain. CT showed a Bosniak type III renal mass. After laparoscopic partial nephrectomy the initial report was cystic nephroma. Immunohistochemical staining was performed being positive for Epithelial Membrane Antigen thus changing the diagnosis to MCRCC. Multilocular cystic renal cell carcinoma cannot reliably be distinguished from cystic nephroma neither by physical examination nor by radiologic evaluation; immunohistochemical staining assay is useful to differentiate between these conditions allowing an accurate diagnosis and proper follow-up.

The spectrum of renal cell carcinoma in adults

The spectrum of renal cell carcinoma (RCC) includes many neoplasms with distinct cytogenetics, biologic behaviors, and imaging appearances. The advent of molecular therapies targeting different tumor types, new insights into the relative roles of biopsy and surveillance for small incidental tumors, and a growing array of nephron-sparing interventions have altered management of RCC. Similarly, the role of the radiologist is changing, and it is becoming increasingly important for radiologists to familiarize themselves with the various types of RCC. This article introduces the reader to the common and uncommon recognized types of renal cell carcinoma and discusses how these neoplasms differ in imaging appearance and behavior.

Preoperative decision making for renal cell carcinoma: cystic morphology in cross-sectional imaging might predict lower malignant potential

OBJECTIVES

Several histologic studies showed more favorable oncologic outcome for renal cell carcinoma (RCC) with cystic change. However, there is no prognostic tool to judge on cystic RCC preoperatively. We hypothesized, that cystic morphology in cross-sectional imaging predicts lower malignant potential.

MATERIALS AND METHODS

From our prospectively conducted oncologic database, we identified 825 patients who underwent surgery for malignant renal tumors between 2001 and 2010. In 348 cases (42%), adequate imaging was available for an independent review by 2 radiologists. We excluded recurrent and synchronous bilateral RCC, familial syndromes, collecting duct carcinoma, and metastases of other origin. For the resulting 319 patients, we compared clinical, pathologic, and survival outcomes.

RESULTS

Median age was 63 (19-88) years and 220 (69%) patients were male. Median follow-up was 1.7 (0-9.8) years. Of 319 renal masses, 277 (86.8%) were solid and 42 (13.2%) were cystic. In cystic RCC, median tumor diameter was lower (3 cm vs. 4 cm, P = 0.002) and nephron-sparing surgery was more frequent (69% vs. 41.5%, P = 0.002). None of the patients with cystic RCC and 56 (20.2%) with solid RCC had synchronous systemic disease (P = 0.001). The nuclear grade of cystic RCC was more favorable (P = 0.002). Patients with cystic RCC showed better overall (P = 0.049) and cancer-specific survival (P = 0.027). In a multivariate model, only synchronous metastases, positive R status, and greater tumor diameter were independent risk factors (P ≤ 0.03).

CONCLUSIONS

We report the first study to show that cystic morphology in cross-sectional imaging might predict RCC with a lower malignant potential. This insight could allow less invasive treatment strategies in selected patients.

[Clinicopathological study and immunohistochemical expression of CA9 in cystic multilocular renal cell carcinomas]

OBJECTIVE

Multilocular cystic renal cell carcinoma has been considered as a distinct subtype of clear cell renal cell carcinoma according to 2004 WHO classification. CA9 has proven to be a diagnostic and prognostic marker for clear cell renal cell carcinoma, but the study has been limited to solid tumors. The aim of this article was to analyse the clinical features of multilocular cystic renal cell carcinoma with focus on CA9 expression.

PATIENTS AND METHODS

Nine multilocular cystic renal cell carcinomas were found. Their age was from 33 to 74 years old with a median of 54 years. There were five men and four women. The computerized tomography was analyzed. There were three total nephrectomies and six partial nephrectomies. The follow-up ranged from five to 102 months with a median 56 months. Immunohistochemical staining was performed on surgical samples to detect CA9 expression.

RESULTS

There were seven pT1a, one pT1b and one pT2; four grade 1 and five grade 2. The Bosniak classification was: one B2F, six B3 and two B4. In CT examination, all tumors showed a hypodense mass. Seven out of nine showed multiple intern septa, more or less thick and vascularized with an enhancement after injection of contrast. No metastasis or relapse was found during follow-up. Eight out of nine multilocular cystic renal cell carcinomas expressed strongly CA9.

CONCLUSION

Multilocular cystic renal cell carcinoma was a low malignant tumor with a good prognosis. The diagnostic criteria based on the WHO classification 2004 should be adopted in routine. CA9 could be a new diagnostic marker for this tumor.

Multilocular cystic renal cell carcinoma in lower pole moiety of a duplex kidney

Multilocular cystic renal cell carcinoma (MCRCC) is an uncommon low-grade renal cell carcinoma with unique morphologic features. The 2004 World Health Organization classification of kidney tumors categorized MCRCC as a separate entity. The authors report the case of a 48-year-old man whose MCRCC originated from the lower portion of the duplex kidney (DK). Because the oncological outcome of MCRCC is favorable, regardless of tumor size and stage, patients with MCRCC might benefit from nephron-sparing surgery. It is important to distinguish larger MCRCCs from other renal cell carcinomas, especially when comorbid with DK, because the characteristic anatomy of DK warrants the nephron-sparing surgery. To the authors' knowledge, MCRCC in DK has not been reported previously in the English literature.

The expanding role of imaging in the management of renal cell carcinoma

The management of renal cell carcinoma (RCC) is evolving owing to the increasing detection of small renal masses, greater understanding of the metabolic pathways involved, new targeted medical treatments for metastatic RCC, and evolving surgical and minimally invasive image-guided treatment techniques. Consequently, the role of imaging and radiology has expanded, with new challenges encompassing all aspects of management, including diagnosis, predicting cell type, staging, preoperative vascular mapping, image-guided treatment and biopsy, detection of recurrence and the use of imaging as a biomarker to assess response to treatment. This article is a comprehensive review of RCC, outlining the etiology of the disease, RCC histological subtypes and their imaging characteristics, imaging modality techniques for evaluation of RCC, treatment strategies and the management of small renal masses.

Multilocular cystic renal cell carcinoma: clinicopathological features and preoperative prediction using multiphase computed tomography

OBJECTIVE

• To analyse the clinicopathological and radiological features of multilocular cystic renal cell carcinoma (MCRCC) and to determine the preoperative factors differentiating MCRCC from other cystic RCC (CRCC).

PATIENTS AND METHODS

• The medical records of 53 patients with complex cystic renal masses evaluated by multiphase computed tomography (CT), surgically removed and confirmed as sporadic RCC were reviewed. • Of these 53 patients, 23 were classified as having MCRCC and 30 as other CRCCs, defined as RCCs with extensive cystic change or cystic necrosis. • Another 22 patients were treated for complex cystic renal masses presumed to be RCC and diagnosed as having benign cyst.

RESULTS

• Benign cysts and MCRCCs were significantly more likely to be of Bosniak classification III than other CRCCs (77% vs 61% vs 27%, P= 0.001). • The mean Hounsfield unit (HU) during the corticomedullary phase (CMP) was significantly higher in other CRCCs, with HU ≥38 having 83% sensitivity and 80% specificity for predicting other CRCCs. • In a multiple regression model, Bosniak classification and mean HU during CMP were independent factors predictive of other CRCCs. • In the 41 patients with masses >4 cm in diameter, the combination of Bosniak classification IV and HU ≥38 during CMP showed 63% sensitivity, 96% specificity, 91% positive predictive value and 80% negative predictive value, yielding 2% false-positive and 15% false-negative rates.

CONCLUSIONS

• The mean HU during CMP and Bosniak classification can differentiate MCRCC from other CRCCs. • This could help in selecting an appropriate surgical method, such as nephron-sparing surgery, for complex cystic renal masses >4 cm.

CA9 as a molecular marker for differential diagnosis of cystic renal tumors

OBJECTIVE

CA9 is proven to be a powerful marker for clear cell renal cell carcinoma. The studies on CA9 have been limited to solid renal cell carcinomas (RCC). We have conducted a study of CA9 expression in renal cystic tumors. The purpose of the present study was to extend the utility of CA9 for cystic renal tumors.

MATERIALS AND METHODS

Immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were used to detect CA9 expression in cystic renal tumors. Forty-three cystic renal tumors (22 benign and 21 malignant) were included for the immunohistochemical staining. Thirty-six patients with a cystic renal mass (20 malignant and 16 benign cystic tumors) were studied to measure CA9 level in the fluid by ELISA. Sixteen cysts (9 malignant and 7 benign cysts) were subjected both to immunohistochemistry and CA9 measurement in the fluid.

RESULTS

Using immunohistochemical staining, all the benign cystic renal tumors including the 18 simple cyst and 4 benign multilocular cystic nephromas did not express CA9. All 13 cystic clear cell RCC were scored as strong staining for CA9. For 8 multilocular clear cell RCC, 7 were scored as strong staining for CA9 and the other one was negative. There was a significant difference in positive percentage (P < 0.001) between the 2 groups of malignant and benign cysts. For the 16 benign cysts, the mean concentration of CA9 in the fluid of cyst was 162 ± 133 pg/ml (median: 0 pg/ml; range: 0-2140 pg/ml). For the 20 malignant renal cystic tumors, the mean concentration of CA9 in the fluid of cyst was 2043 ± 62 pg/ml (median: 2,140 pg/ml; range: 1,112-2,140 pg/ml). There was a significant difference in mean concentration of CA9 between the two groups of malignant and benign cysts (P < 0.001). The presence or absence of CA9 expression measured by immunohistochemistry and ELISA test was concordant in 14 out of 16 cases (88%).

CONCLUSIONS

Malignant cystic renal tumors expressed strongly CA9 while the benign renal cysts did not express CA9. CA9 can be detected in the fluid of malignant cystic renal tumors. CA9 is a promising molecular marker to differentiate the malignant cystic renal tumors from the benign cysts.

Renal cystic diseases and renal neoplasms: a mini-review

The past two decades have witnessed recognition of several new types of renal cell carcinoma, each with distinct cytogenetic abnormalities. Included are several genetic and acquired cystic kidney diseases associated with development of renal cell carcinoma, the topic of this review. The risk in patients with autosomal dominant polycystic kidney disease is not accurately known but may be slightly increased. The risk for patients with von Hippel-Lindau disease is substantial, and death from renal cancer is common. For patients with tuberous sclerosis complex, the challenge is recognition of the occasional malignancy arising in a field of many benign tumors. Patients with end-stage kidney disease and acquired cystic kidney disease may develop a variety of renal cell carcinoma types. Progress in understanding the molecular basis of renal cyst formation and neoplastic disease has fostered development of targeted therapies that now hold promise for a group of neoplasms whose cure was traditionally dependent on surgical approaches.

Clinical and radiologic features of cystic renal masses

OBJECTIVE

The purpose of our study was to review the clinical correlates and imaging features of benign and malignant cystic renal masses.

CONCLUSION

This article reviews the radiologic findings of cystic renal lesions. After completing this article, readers should be able to recognize the more common complex cystic renal lesions.

[The cystic component in the renal cancer: conceptual overiew]

The renal cancer (RC) cystic component is on the radiological tests and could be consolidate with pathological analysis. The concepts "cystic renal cancer" or "cystic renal tumor" contain a group of entities range from cystic grown pattern RCs to pseudocystic tumors as well as cystic renal diseases coinciding with the RC. The CR and the cystic renal diseases have a great variety to sorts of presentations, giving different ways of radiological images, blending solid and cystic areas. Some papers use indiscriminately expression "cystic" without pathologic proof. Just cystic grown pattern RCs and multilocular cystic carcinoma could be named "cystic renal tumors". For de rest, especially over image study, is more suitable to use expressions as "renal tumor of cystic configuration", while pathologic report are available.

[Renal tumors]

This pictural essay presents the different imaging patterns of the main renal tumor processes described in the latest pathological classification. Most of them make it possible to suggest certain histological types in order to modify the surgical approach.