Renal cell carcinoma in acquired cystic kidney disease: volume growth rate determined by helical computed tomography

Imaging of haemodialysis: renal and extrarenal findings

Electrolyte alterations and extra-renal disorders are quite frequent in patients undergoing haemodialysis or peritoneal dialysis. The native kidneys may be the site of important pathologies in patients undergoing dialysis, especially in the form of acquired renal cystic disease with frequent malignant transformation. Renal neoplasms represents an important complication of haemodialysis-associated acquired cystic kidney disease and imaging surveillance is suggested. Extra-renal complications include renal osteodistrophy, brown tumours, and thoracic and cardiovascular complications. Other important fields in which imaging techniques may provide important informations are arteriovenous fistula and graft complications.

Teaching points

• Renal neoplasms represent a dreaded complication of haemodialysis.

• In renal osteodystrophy bone resorption typically manifests along the middle phalanges.

• Brown tumours are well-defined lytic lesions radiographically, possibly causing bone expansion.

• Vascular calcifications are very common in patients undergoing haemodialysis.

• Principal complications of the AV fistula consist of thrombosis, aneurysms and pseudoaneurysms.

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.

Volume doubling time and growth rate of renal cell carcinoma determined by helical CT: a single-institution experience

The purpose of this study was to retrospectively evaluate the volume doubling time (VDT) and growth rate of renal cell carcinomas (RCC) on a serial computed tomography (CT) scan. Thirty pathologically proven RCCs were reviewed with helical CT. Each tumor underwent at least two CT scans. Tumor volume was determined using an area measuring tool and the summation-of-areas technique. Growth rate was evaluated in terms of diameter and volume changes. VDT and volume growth rate were compared in relation to several factors (initial diameter, initial volume, diameter growth rate, volume growth rate, tumor grade, tumor subtype, sex or age). Mean VDT of RCCs was 505 days. Mean diameter and volume growth rate were 0.59 cm/year and 19.1 cm(3)/year, respectively. For volume and diameter growth rate, tumors < or =4 cm showed lower rates than those >4 cm (P < 0.01). VDT was weakly negatively correlated with diameter growth rate (P > 0.05). Volume growth rate was moderately to strongly positively correlated with initial diameter, initial volume and diameter growth rate (P < 0.05). In conclusion, small RCCs grew at a slow rate both diametrically and volumetrically. More accurate assessment of tumor growth rate and VDT may be helpful to understand the natural history of RCC.

Percutaneous radiofrequency ablation of renal tumours: Case series of 11 tumours and review of published work

Detection of renal cell carcinoma (RCC) is increasing with the greater use of cross-sectional imaging and up to two-thirds of RCCs are discovered incidentally in asymptomatic patients. The traditional option of nephrectomy or partial nephrectomy may not always be appropriate. A minimally invasive treatment alternative is radiofrequency ablation (RFA). We retrospectively reviewed the RFA cases for renal tumours at our institution between January 2004 and June 2006. Thirteen RFA treatment sessions were conducted for 11 neoplasms in 11 patients. Mean patient age was 74.4 years (61-88 years). Imaging was carried out after ablation with a mean follow up of 8.0 months (2-26 months). No residual tumour was observed after the first RFA treatment in 82% of patients (nine of 11). Two patients required a second RFA treatment for residual (one) or recurrent tumour (one). RFA is emerging as a useful technique for treatment of small renal tumour. A number of short-term studies reflect this, however, long-term findings are still lacking.

Computed tomography of renal cell carcinoma in patients with terminal renal impairment

PURPOSE

An increased incidence of renal tumors has been observed in patients with end-stage-renal-disease (ESRD). The very strong association with acquired renal cystic disease (ACRD) and increased incidence of the renal tumors (conventional renal cell carcinoma (CRCC), papillary renal cell carcinoma (PRCC) or papillary renal cell adenoma (PRCA)) was reported. This study discusses the role of computed tomography (CT) in detecting renal tumors in patients with renal impairment: pre-dialysis, those receiving dialysis or with renal allograft transplants.

MATERIALS AND METHODS

Ten patients (nine male, one female) with renal cell tumors were enrolled into a retrospective study; two were new dialysis patients, three on long-term dialysis, and five were renal transplant recipients with history of dialysis. All patients underwent helical CT, a total of 11 procedures were performed. Sixteen-row detector system was used five times, and a 64-row detector system for the six examinations. All patients underwent nephrectomy of kidney with suspected tumor, 15 nephrectomies were performed, and 1 kidney was assessed during autopsy. CT findings were compared with macroscopic and microscopic assessments of the kidney specimen in 16 cases.

RESULTS

Very advanced renal parenchyma atrophy with small cysts corresponding to ESRD was found in nine patients, chronic pyelonephritis in remained one. A spontaneously ruptured tumor was detected incidentally in one case, patient died 2 years later. In the present study, 6.25% (1/16) were multiple PRCA, 12.5% (2/16) were solitary PRCC, 12.5% tumors (2/16) were solitary conventional renal cell carcinomas (CRCC's), 12.5% tumors (2/16) were multiple conventional renal cell carcinomas (CRCC's), 25% (4/16) were CRCC's combined with multiple papillary renal cell carcinomas with adenomas (PRCC's and PRCA's), and 25% (4/16) of the tumors were multiple PRCC's combined with PRCA's without coexisting CRCC's. Bilateral renal tumors were found in our study in 60% (6/10) confirmed in six cases, one kidney left on follow-up due to the small tumors.

CONCLUSIONS

With the use of a multi-detector row system, it is possible to detect smaller foci suspected to originate in multiple tumors, especially when up to 3-mm thin multi-planar reconstructions are used. Two cases demonstrated the possibility the development of RCC in impaired kidneys may start before dialysis initiation.

Expectant management for the treatment of small renal masses

The incidence of small renal masses that are detected incidentally is increasing, particularly in patients who are in advanced age and with increased comorbidities. We review the available data on the nature and natural history of these small renal tumors, and observe that based on the limited available information, most of these lesions appear to grow slowly. We also review the currently available markers of tumor progression. We postulate that because of tumor heterogeneity, it is unlikely that advancement in prognostic knowledge will be gained using current approaches, such as histologic characteristics and tumor size, and that there is a clear need for new biomarkers. We conclude that expectant management is a viable and safe option for the patient with a short life expectancy but potentially unsafe outside a well-controlled clinical trial in the younger and fit patient.

Calcium Oxalate Deposition in Renal Cell Carcinoma Associated With Acquired Cystic Kidney Disease

The main complication of acquired cystic kidney disease (ACKD) is frequent development of renal tumors, including renal cell carcinoma (RCC). Intratumoral deposition of calcium oxalate (CaOx) is a distinct feature of ACKD-associated RCCs, but several features of this type of RCC are not known. Features of the 30 end-stage renal disease (ESRD)-associated RCCs identified within a 13-year period, including eight with CaOx deposition, were analyzed. Pathologic and clinical features of CaOx positive (+) and negative (-) RCCs were evaluated and compared. The CaOx+ RCCs showed higher tendency for bilaterality and multifocality. Seven tumors displayed distinctive morphologic features characterized by tumor cells with ill-defined cell membrane, abundant granular eosinophilic cytoplasm, large nuclei, and prominent nucleoli. One tumor was of clear cell type. Regardless of histologic type, all tumors displayed a proximal tubular differentiation. No significant difference was noted for tumors' stage, proliferation, and apoptosis rate between the CaOx+ and CaOx- RCCs. CaOx+ RCCs account for a significant portion of all ESRD-associated RCCs. The majority of these RCCs display a distinctive morphologic profile. Proximal tubular cell differentiation in conjunction with ESRD-mediated high serum level may be pathogenetically important for intratumoral CaOx deposition. These RCCs seems to have a relatively good prognosis.

The natural history of incidentally detected small renal masses

BACKGROUND

The incidence of renal cell carcinoma (RCC) is increasing, largely due to the widespread use of cross-sectional imaging. Most renal tumors are detected incidentally as small, asymptomatic masses. To study their natural history, the authors prospectively followed a series of patients with this type of lesion who were unsuited for or refused surgery.

METHODS

Twenty-nine patients with 32 masses that measured < 4 cm in greatest dimension (25 solid masses and 7 complex cystic masses) were studied. The primary outcome was tumor size, which was calculated as volume over time. All patients were followed with serial abdominal imaging, and each mass had at least three follow-up measurements. The median follow-up was 27.9 months (range, 5.3-143.0 months).

RESULTS

Overall, the average growth rate did not differ statistically from zero growth (P = 0.09; 95% confidence interval, - 0.005-0.2 cm per year) and was not associated with either initial size (P = 0.28) or mass type (P = 0.41). Seven masses (22%) reached 4 cm in greatest dimension after 12-85 months of follow-up. Eight masses (25%) doubled their volumes within 12 months. Overall, 11 masses (34%) fulfilled 1 of these 2 criteria of rapid growth. Nine tumors were removed surgically after an average of 3.1 years of follow-up because it was believed that they were growing fast. No patient had disease progression.

CONCLUSIONS

Approximately one-third of small renal masses that are presumed RCCs grow if they are managed conservatively and are followed with serial imaging. The growth rate is slow or undetectable in the majority of patients. These observations raise the possibility of a period of initial observation in selected patients, particularly the elderly or infirm.

Ultrasonography in chronic renal failure

Many chronic renal diseases lead to the final common state of decrease in renal size, parenchymal atrophy, sclerosis and fibrosis. The ultrasound image show a smaller kidney, thinning of the parenchyma and its hyperechogenicity (reflecting sclerosis and fibrosis). The frequency of renal cysts increases with the progression of the disease. Ultrasound generally does not allow for the exact diagnosis of an underlying chronic disease (renal biopsy is usually required), but it can help to determine an irreversible disease, assess prognosis and avoid unnecessary diagnostic or therapeutic procedures. The main exception in which the ultrasound image does not show a smaller kidney with parenchymal atrophy is diabetic nephropathy, the leading cause of chronic and end-stage renal failure in developed countries in recent years. In this case, both renal size and parenchymal thickness are preserved until end-stage renal failure. Doppler study of intrarenal vessels can provide additional information about microvascular and parenchymal lesions, which is helpful in deciding for or against therapeutic intervention and timely planning for optimal renal replacement therapy option.

Prevalence of renal cell carcinoma in patients with ESRD pre-transplantation: a pathologic analysis

BACKGROUND

Acquired renal cystic disease (ARCD), renal adenoma (AD), and renal cell carcinoma (RCC) are more common in patients with end-stage renal disease (ESRD). However, the prevalence of these conditions in patients undergoing transplantation, and the clinical characteristics associated with their occurrence are unclear.

METHODS

At our institution, the majority of patients undergo an ipsilateral native nephrectomy at the time of transplantation, providing a unique opportunity to study the prevalence and pathology of ARCD, AD and RCC in ESRD. We retrospectively reviewed all consecutive nephrectomy pathology reports over a six year period. Demographic and clinical characteristics associated with these lesions were identified.

RESULTS

Two hundred and sixty nephrectomy reports were reviewed: ARCD, AD, RCC and oncocytoma were found in 33%, 14%, 4.2% and 0.6% of cases, respectively. On multivariable analysis, ARCD was positively associated with male sex and longer dialysis duration and negatively associated with peritoneal dialysis. Similarly, AD was positively associated with male sex, longer dialysis duration and greater age. There was a trend for RCC cases to share similar associations although the small total number of cases precluded findings of statistical significance.

CONCLUSION

By pathologic analysis, renal tumors are more common in the pre-transplant ESRD population than previously reported (using radiologic methods). Our study also identifies risk factors for their occurrence. This may prove useful in designing screening studies for renal tumors in this patient population.