Cystic Renal Lesions Research Articles

Correlation of the feline PKD1 genetic mutation with cases of PKD diagnosed by pathological examination

Autosomal-dominant polycystic kidney disease (AD-PKD) is the most prevalent inherited genetic disease of cats, particularly affecting Persians. Using archived tissue samples from 44 cats a genotype was successfully obtained by real-time PCR for 43 cats. Twenty-five cats (18 Persians, 4 domestic longhair cats and 3 domestic shorthair (DSH) cats) were found to carry the AD-PKD mutation and all of these cats had macroscopic and/or microscopic evidence of renal cysts consistent with PKD. Eighteen cats were found to be wild-type. Twelve of these (all Persians) had no pathological evidence of PKD, but the remaining 6 cats had evidence of renal cystic lesions. On pathological review the cystic lesions in 4 (2 Persians and 2 DSH) of these 6 cats were considered not to be consistent with a primary diagnosis of PKD. Histological evidence of polycystic kidneys was, however, confirmed in the remaining 2 cats (1 DSH and 1 Bengal) and may indicate that other PKD-causing mutations exist in the feline population.

Update on radiological imaging of renal cell carcinoma

US is frequently used as the initial imaging in patients with suspected renal disease. US contrast agents offer the potential to increase the sensitivity in patients who cannot undergo CT or MTI. Harmonic imaging has helped with the evaluation of renal cystic lesions. CT remains the reference standard for staging and lesion characterization. The rapid technological advances mean that ultra-thin slices and 3D imaging have now become more widely available. MRI has also greatly advanced in speed and image quality, but at present, imaging time and scanner availability mean that MRI is generally used as a problem-solving tool. It is particularly helpful for smaller lesions and complex cystic lesions, where subtraction can be used to accurately identify the presence of enhancement. MRI is used as the primary diagnostic tool for patients with radiation concerns and those with renal failure. Caution must now also be taken in these patients, given the recent studies raising the association of gadolinium-based compounds and NSF. There have been dramatic improvements in renal imaging over the last decade, offering better resolution, shorter imaging times and better patient acceptance. The progress in minimally invasive techniques has driven the need to provide better preoperative information to the surgeon. The future of renal imaging is an exciting field; perhaps with fluorodeoxyglucose-based positron emission tomography we will be able to predict the biological behaviour of a tumour, and molecular imaging agents will become available to identify and hopefully treat specific tumour types.

Evolving Concepts of Cystic Renal Lesions

A subset of cystic renal lesions with a complex architecture and varying amounts of stroma includes cystic nephroma and mixed epithelial and stromal tumor of the kidney. Both these lesions are rare, and their histogenesis is unclear. Until recently, cystic nephroma was diagnosed in adults and in children. However, recognition of differences in the clinical phenotype between pediatric and adult cystic nephromas and appreciation of the morphologic spectrum of Wilms tumor has led to the inclusion of pediatric cystic nephroma-like lesions into the spectrum of nephroblastoma. Hence, pediatric cystic nephroma-like lesions are considered to represents the most differentiated end of the spectrum of Wilms tumor. The concept of cystic lesions in adults is still evolving. Currently, cystic nephroma is recognized as an exclusively adult lesion that is composed of thin septa and cysts lined by flattened, cuboidal, or hobnail epithelium. In contrast, mixed epithelial and stromal tumor of the kidney has grossly recognizable spindle cell stroma in which tubules and cysts are embedded. However, most recently, this distinction has been challenged and the similarities between these 2 lesions have been emphasized, suggesting that both lesions may represent opposite ends of the spectrum of the same pathologic entity. In this paper, we present 2 adult cystic lesions: each represents a “classic” example of cystic nephroma and mixed epithelial and stromal tumor of the kidney. The clinical phenotype, morphology, and immunohistochemistry of both lesions are compared. The current literature is reviewed, and the potential relationship between these 2 cystic lesions is discussed.

Angiomyolipoma With Epithelial Cysts (AMLEC)

Renal angiomyolipoma (AML) is typically a solid lesion, composed of varying amounts of adipose, vascular, and muscular tissue, lacking an epithelial component. Although it is known that entrapped renal tubules may be observed in AML, presentation as a cystic mass has not been previously reported. We report the clinicopathologic and immunohistochemical features of four cystic renal AML. The lesions were found in 2 male and 2 female patients, ranging in age from 37 to 76 years, none with a history of hormonal therapy. One of the four patients had known tuberous sclerosis, and this patient and 1 other presented with bilateral cystic renal lesions. Grossly, the lesions measured between 1.3 and 4.5 cm in greatest dimension. Histologically, the lesions were each composed of three components: 1) epithelial cysts lined by cuboidal to hobnail cells; 2) a compact subepithelial "cambium-like" layer of cellular, müllerian-like AML stroma with prominent admixed chronic inflammation; and 3) muscle-predominant AML with associated dysmorphic blood vessels exterior to the cellular subepithelial stroma. Immunohistochemically, the stromal components of all four lesions labeled with HMB-45 and Melan-A, most intensely in the cellular subepithelial stroma, whereas smooth muscle actin and desmin demonstrated the opposite pattern, with greatest intensity in the muscle-predominant AML areas. Immunoreactivity for estrogen and progesterone receptors (ER, PR) and CD10 was present in all cases, with strongest and most diffuse staining in the subepithelial AML cells. The cyst lining cells were positive for pancytokeratin and soy bean agglutinin (the latter characteristic of distal nephron epithelium) but did not label for ER, PR, or melanocytic markers. Although these distinctive lesions may be confused with mixed epithelial-stromal tumor, their lack of female predominance or association with hormone therapy, their distinctive dysplastic blood vessels and disorganized exterior muscular layer, along with their immunohistochemical profile, support their classification as AML with epithelial cysts. Whereas the cysts appear to arise primarily from entrapped collecting ducts, the peculiar subepithelial condensation of AML stromal cells, with morphologic and immunohistochemical features suggesting differentiation toward endometrial stroma, may represent epithelial-induced müllerian differentiation not previously reported in AML.

Intraoperative Pathology Consultation for Kidney and Urinary Bladder Specimens

Intraoperative pathology consultation for kidney and urinary bladder specimens is relatively infrequent. Scant literature is devoted to this topic. The clinical indications and diagnostic usefulness and pitfalls of intraoperative pathology consultation of kidney and urinary bladder specimens will be reviewed, based on literature and personally encountered cases. The indications for intraoperative pathology consultation for renal lesions included (1) surgical margins in partial nephrectomy specimens, (2) solid renal mass in unusual clinical or radiologic settings, (3) synchronous renal and extrarenal masses, (4) cystic renal lesions, (5) ureteral surgical margin for transitional cell carcinoma, (6) multiple renal masses, (7) solid mass in a diffusely cystic kidney, and (8) evaluation of renal injury. The indications for urinary bladder included (1) status of the surgical margins, (2) diagnosis of bladder tumor biopsy, (3) diagnosis of extravesical tumors with vesical extension, (4) diagnosis of extravesical mass, including pelvic lymph nodes encountered during cystectomy, and (5) status of bladder neck margin during radical prostatectomy for cancer. The frequent problematic areas for the kidney included misdiagnosis or incorrect classification of cystic tumors or spindle cell tumors, and confusion of clear cell renal cell carcinoma with inflammatory lesions. The problematic areas for urinary bladder included the differential diagnoses of high-grade dysplasia/carcinoma in situ with reactive changes at the ureteral or urethral surgical margins. Distinctive indications and diagnostic pitfalls are recognized for intraoperative consultation of renal or urinary bladder lesions. Awareness of the pertinent problems should improve diagnostic accuracy and facilitate the proper management of these lesions.

LAPAROSCOPIC PARTIAL NEPHRECTOMY FOR CYSTIC MASSES

Although laparoscopic partial nephrectomy (LPN) has emerged as an effective treatment option in select patients with a solid renal tumor, scant data are available on cystic renal tumors. We report our experience with LPN in 50 patients with a cystic renal lesion. Of 284 patients undergoing LPN at our institution since August 1999 preoperative computerized tomography identified a suspicious cystic lesion in 50 (17.6%) (group 1). Data were retrospectively compared with those on 50 matched, consecutive patients undergoing LPN for a solid renal mass (group 2). All patients with Bosniak II/IIF cysts were advised to undergo watchful waiting. Surgery was offered if the cyst changed in character or if that was the patient preference. Median tumor size was 3 cm in group 1 and 2.6 cm in group 2 (p = 0.07). Groups 1 and 2 were comparable in regard to perioperative parameters. In patients with Bosniak II (9), IIF (4), III (12) and IV (21) cysts final histopathology revealed renal cell carcinoma in 22%, 25%, 50% and 90%, respectively. All 100 patients had a negative surgical margin. No patient in group 1 had intraoperative puncture/spillage of the cystic tumor. In group 1 during a mean followup of 14 months (range 1 month to 3 years) 1 patient had retroperitoneal recurrence at 1 year despite negative surgical margins during initial LPN. Surgical outcomes of LPN for suspicious cystic masses are similar to those of LPN for solid tumors. However, extreme caution and refined laparoscopic technique must be exercised to avoid cyst rupture and local spillage.

Case Report: A Cystic Renal Lesion in a 15-month-old Girl with Discrepancy in Ultrasound and CT Appearances

Case Report: A Cystic Renal Lesion in a 15-month-old Girl with Discrepancy in Ultrasound and CT Appearances

Complementary role of MRI after sonography in assessing bilateral urinary tract anomalies in the fetus.

The objectives of our study were to evaluate the contribution of adding MRI findings to inconclusive sonographic data when assessing fetal urinary tract anomalies and to determine how this addition may affect the management of pregnancy. SUBJECTS AND METHODS. We prospectively used MRI to study 16 third-trimester fetuses in whom sonography suggested bilateral urinary tract anomalies but failed to provide a definite diagnosis. These anomalies included enlarged hyperechoic kidneys (n = 6), bilateral pelvicaliceal dilatation (n = 6), renal cystic lesions (n = 2), and renal agenesis associated with severe oligohydramnios (n = 2). The addition of MRI to sonography modified the diagnosis in five fetuses. In a fetus with suspected bilateral ureteropelvic obstruction, the diagnosis of bilateral ureterohydronephrosis associated with reflux or ureterovesical junction obstruction was made. In a fetus with an enlarged bladder at 32 weeks' gestational age, a possible diagnosis of megacystic microcolon was excluded on the basis of the normal appearance of the colon. In two fetuses with enlarged hyperechoic kidneys, MRI showed localized medullary hyperintense lesions suggesting autosomal recessive polycystic kidney disease in one fetus and medullary cystic dysplasia in another fetus with Jeune's syndrome. In a patient with suspected unilateral renal agenesis, MRI showed bilateral agenesis. In four fetuses, the addition of MRI to sonography led to a diagnosis that modified the decision to continue or terminate the pregnancy. MRI can accurately show many urinary tract anomalies in third-trimester fetuses. It may be a useful complementary tool in the assessment of bilateral urinary tract anomalies of fetuses, particularly in cases with inconclusive sonographic findings.

Intraoperative Consultation for Renal Lesions: Implications and Diagnostic Pitfalls in 324 Cases

Intraoperative consultation rarely is requested for lesions in the kidney. Of 324 renal lesions submitted for gross or frozen section intraoperative consultation, 199 specimens were submitted for gross consultation only; no diagnostic pitfalls were noted. The clinical implications and diagnostic pitfalls in 125 specimens submitted for frozen section were the focus of our study. Frozen section intraoperative consultation was requested to evaluate surgical margins in partial nephrectomy specimens, solid renal mass in an unusual clinical or radiologic setting, synchronous renal and extrarenal masses, cystic renal lesion, ureteral surgical margins for transitional cell carcinoma, multiple renal masses, solid mass in a diffusely cystic kidney, and renal injury. Among the 125 cases, the diagnoses were deferred in 17 (6 renal cell carcinomas with granular cytoplasm, 7 cystic lesions, 3 metastatic tumors, 1 leiomyoma). The frozen section diagnoses were incorrect owing to limited sampling in 5 and misinterpretation in 4 (melanoma vs angiomyolipoma, lymphoma vs angiomyolipoma, benign cyst vs cystic renal cell carcinoma, metastatic renal cell carcinoma vs pheochromocytoma). Awareness of distinctive indications for frozen section intraoperative consultation and diagnostic pitfalls should improve diagnostic accuracy and facilitate proper management of these lesions.

Intraoperative Consultation for Renal Lesions

Intraoperative consultation rarely is requested for lesions in the kidney. Of 324 renal lesions submitted for gross or frozen section intraoperative consultation, 199 specimens were submitted for gross consultation only; no diagnostic pitfalls were noted. The clinical implications and diagnostic pitfalls in 125 specimens submitted for frozen section were the focus of our study. Frozen section intraoperative consultation was requested to evaluate surgical margins in partial nephrectomy specimens, solid renal mass in an unusual clinical or radiologic setting, synchronous renal and extrarenal masses, cystic renal lesion, ureteral surgical margins for transitional cell carcinoma, multiple renal masses, solid mass in a diffusely cystic kidney, and renal injury. Among the 125 cases, the diagnoses were deferred in 17 (6 renal cell carcinomas with granular cytoplasm, 7 cystic lesions, 3 metastatic tumors, 1 leiomyoma). The frozen section diagnoses were incorrect owing to limited sampling in 5 and misinterpretation in 4 (melanoma vs angiomyolipoma, lymphoma vs angiomyolipoma, benign cyst vs cystic renal cell carcinoma, metastatic renal cell carcinoma vs pheochromocytoma). Awareness of distinctive indications for frozen section intraoperative consultation and diagnostic pitfalls should improve diagnostic accuracy and facilitate proper management of these lesions.

Localized cystic disease of the kidney: CT findings.

We assessed the clinical and computed tomographic (CT) features of localized cystic disease of the kidney and how these features differentiate this disease from other renal cystic diseases. Medical records and CT scans of seven patients with localized cystic disease were reviewed retrospectively. Pathologic confirmation in five patients was done by surgery. The subjects consisted of four males and three females, with an age range of 29-74 years. Localized cystic disease in five patients was an incidental finding. Clinical presentations in the other two patients included dark urine color, palpable flank mass, and generalized weakness. There was no patient with impairment of renal function associated with renal cystic disease. Six patients had cystic renal lesions in the left kidneys, and one patient had lesions in the right kidney. Six patients had cysts in a localized area in the affected kidney, and the remaining patient had diffuse involvement of the entire kidney. The upper pole was most frequently involved. CT appearance was characterized by multiple, variable size cysts conglomerated to islets of cysts that were separated by the normal renal parenchymal band. Localized cystic disease of the kidney has characteristic CT findings that distinguish it from other renal cystic diseases, making follow-up without surgical intervention possible.

Solid renal tumor severity in von Hippel Lindau disease is related to germline deletion length and location.

von Hippel Lindau disease (VHL) is an autosomal dominant familial cancer syndrome linked to alteration of the VHL tumor suppressor gene. Affected patients are predisposed to develop pheochromocytomas and cystic and solid tumors of the kidney, CNS, pancreas, retina, and epididymis. However, organ involvement varies considerably among families and has been shown to correlate with the underlying germline alteration. Clinically, we observed a paradoxically lower prevalence of renal cell carcinoma (RCC) in patients with complete germline deletion of VHL. To determine if a relationship existed between the type of VHL deletion and disease, we retrospectively evaluated 123 patients from 55 families with large germline VHL deletions, including 42 intragenic partial deletions and 13 complete VHL deletions, by history and radiographic imaging. Each individual and family was scored for cystic or solid involvement of CNS, pancreas, and kidney, and for pheochromocytoma. Germline deletions were mapped using a combination of fluorescent in situ hybridization (FISH) and quantitative Southern and Southern blot analysis. An age-adjusted comparison demonstrated a higher prevalence of RCC in patients with partial germline VHL deletions relative to complete deletions (48.9 vs. 22.6%, p=0.007). This striking phenotypic dichotomy was not seen for cystic renal lesions or for CNS (p=0.22), pancreas (p=0.72), or pheochromocytoma (p=0.34). Deletion mapping revealed that development of RCC had an even greater correlation with retention of HSPC300 (C3orf10), located within the 30-kb region of chromosome 3p, immediately telomeric to VHL (52.3 vs. 18.9%, p <0.001), suggesting the presence of a neighboring gene or genes critical to the development and maintenance of RCC. Careful correlation of genotypic data with objective phenotypic measures will provide further insight into the mechanisms of tumor formation.

Multiple Renal Cystic Lesions and Acute Renal Failure in Non-Hodgkin's Testicular Lymphoma—A Case Report

Multiple Renal Cystic Lesions and Acute Renal Failure in Non-Hodgkin's Testicular Lymphoma—A Case Report

Calcification in cystic renal masses: is it important in diagnosis?

To determine whether the presence of calcifications in cystic renal masses is important in diagnosis and to suggest an approach to the management of calcified cystic renal masses. Eighty-one cystic renal masses containing calcification in a wall or septum were evaluated by means of review of computed tomographic (CT) images (n = 81), follow-up CT images (n = 28), and results of pathologic examination (n = 40) by the authors in consensus. Images were evaluated for lesion size, amount and morphology of calcification, and any association of calcification with soft-tissue structures. Lesions were categorized according to the Bosniak cyst classification system; the amount of calcification was determined with a subjective grading system. Progression of calcification was qualitatively determined with available follow-up CT scans. Twenty-one lesions were Bosniak category II (benign) and showed small amounts and thin strands of calcification. Nineteen lesions containing more extensive calcification but no enhancing tissue were category IIF. Follow-up CT results available for 16 of these lesions (average follow-up length, 5 years 8 months) showed no substantial change. The three remaining lesions were proved benign at surgery. Twenty-five lesions were category III; surgical intervention was performed in 21 of these (benign, n = 12; malignant, n = 9). Sixteen lesions that contained obvious areas of enhancing soft tissue were category IV and proved malignant at surgery. Calcification in a cystic renal mass is not as important in diagnosis as is the presence of associated enhancing soft-tissue elements. This information should enable a reasonable approach to the management of calcium-containing renal cystic lesions.

Expression of Matrix Metalloproteinase in the Fluids of Renal Cystic Lesions

Cystic lesions of the kidney are common conditions usually diagnosed by imaging. Although simple cysts are easy to diagnose, preoperative diagnosis of a complicated cystic lesion can be difficult. There is little information available on the biological activity of cystic fluid and associations with clinicopathological findings. We analyzed the expression of matrix metalloproteinase (MMP) in the fluids of benign and malignant renal cystic lesions to clarify matriolytic activities in the cyst. Included in this study were 22 samples of cystic fluids from renal cystic lesions, including 14 benign cysts and 8 cystic renal cell carcinomas. MMP-2 and 9 was determined in fluids using gelatin zymography and enzyme-linked immunosorbent assay. MMP-2 expression was ubiquitously observed on zymography except for 2 benign cysts associated with acquired cystic disease of the kidney. MMP-9 was detected in 7 of 8 carcinomas but in only 2 of 14 benign cysts (p <0.01). The concentration of MMP-2 and 9 was significantly higher in cystic carcinomas than in benign cysts (p <0.01). Our data show that MMPs were detectable in cystic fluids in the presence of renal cystic changes. MMP-2 and 9 are more abundant in cystic carcinoma fluids than in benign cystic fluids. These observations suggest that matriolytic enzymes in renal cystic fluid reflect biological aggressiveness and in part explain the pathogenesis of renal cystic lesions.

Expression of Matrix Metalloproteinase in the Fluids of Renal Cystic Lesions

Expression of Matrix Metalloproteinase in the Fluids of Renal Cystic Lesions

Unilateral renal cystic disease – report of one case and review of literature

Clinical presentation of unilateral renal cystic disease (URCD) is characterized by multiple simple cysts in only 1 kidney. Involvement of other intra-abdominal organs is not found. Renal function is usually preserved despite the existence of multiple cysts. No genetic background can be delineated up to the present. We present 1 patient with URCD, who was evaluated for his right flank pain. Urinalysis and biochemical tests showed normal renal function (BUN 5.03 mmol/l, creatinine 110.5 micromol/l). Ultrasonographic examination was done and it revealed 2 right renal stones. Furthermore, multiple renal cysts over the juxta-medullary area were noted. His left kidney was intact. Computed tomography (CT) of both kidneys confirmed this finding. 99mTc-DTPA renal scan showed that the glomerular filtration rate of both kidneys was not significantly different. There was no family history of renal diseases. His parents, grandparents and siblings were examined for possible kidney lesions, but none of them had any renal cystic lesion. This patient was followed for only a relatively short period of time (3 years) and his renal function did not deteriorate. Follow-up image studies with sonography and CT were not different from the previous ones.

Color Doppler ultrasound for detection of renal arteriovenous fistulas

Renal arteriovenous (AV) fistula is uncommon, but sometimes causes severe hematuria. To assess the value of color Doppler ultrasound (CD-US) for the detection of renal AV fistula, we retrospectively reviewed our experience with this disease. Between 1994 and 2001, five patients with renal AV fistula were diagnosed in our institution. Post-biopsy AV fistula of the transplanted kidney was found in 1 patient. Renal AV fistula was detected in 2 patients who presented with gross hematuria. In the remaining 2 patients, renal AV fistula was discovered incidentally during abdominal ultrasonography. We evaluated gray-scale and CD-US imaging in those five patients. In all 5 patients, CD-US showed a whirling flow pattern within an echo-free structure suggesting AV fistula. However, it was difficult to distinguish AV fistula from aneurysm using only CD-US. While pulsed spectral Doppler evaluation of the lesion might be helpful, prompt venous filling on dynamic CT scan and/or renal arteriography was the most definitive sign for diagnosing the renal AV fistula. CD-US is excellent for demonstrating turbulent blood flow signals within the kidney. However, another radiographic study is required to give a definite diagnosis of renal AV fistula. Due to its low cost, low risk and wide availability, we recommend that CD-US be the first-line imaging procedure for the evaluation of hematuria and renal cystic lesion as well as for followup for renal AV fistula.

ATYPICAL INITIAL MANIFESTATION OF ACUTE PYELONEPHRITIS IN CONTINUOUS IMAGE STUDY: RENAL CYSTIC FEATURE

Renal infection, including acute and chronic pyelonephritis, focal bacterial nephritis, renal and perinephric abscess, pyonephrosis and others, represents a spectrum of interrelated conditions. In recent years, computed tomography, ultrasound, nuclear scintigraphy, excretory urography (IVP) and magnetic resonance imaging have offered varying degrees of utility in evaluating renal infection. Although imaging in acute pyelonephritis has been extensively studied, this condition is a rare initial presentation as a renal cystic feature. This investigation presents a case of acute pyelonephritis, with an atypical initial imaging manifestation in renal cystic feature, which became a heterogeneous mass during follow up, and disappeared after treatment. Two conclusions can be drawn: first, a renal cystic lesion may be an initial presentation of acute pyelonephritis; secondly, the abnormalities of the ultrasonography imaging study of renal pyelonephritis persisted and progressed despite the improvement in clinical symptoms and laboratory findings, and displayed complete resolution of imaging abnormalities several months later.

Renal Microcystic Tubular Lesions in Two 1Year-old Dogs – An Early Sign of Hereditary Renal Cystadenocarcinoma?

As a part of a study of early renal changes in renal cystadenocarcinoma (RC), a 5-year-old German shepherd dog and two 1-year-old German shepherd mixed-breed dogs were examined. All three animals had bilateral, microscopic renal cysts, and the 5-year-old dog also had RC. Microscopical examination showed papillary hyperplastic tubular epithelial cells lining the inner wall of the renal cysts in all dogs. These cells showed strong reactivity with a monoclonal antibody against a broad-spectrum type of cytokeratin. The dam of the young dogs had suffered from autosomal dominant inherited RC and nodular dermatofibrosis (ND) syndrome. It is likely that the microscopic renal cystic lesions seen in the young dogs represented an early renal change in the RC/ND syndrome. This suggests that the diagnosis of RC can be made on suspected carriers by microscopical examination of renal biopsies as early as 1 year of age, i.e., before the dogs are used for breeding.