Renal cell carcinoma originating in the free wall of simple renal cyst: Two unusual case reports with literature review

Association between serum uric acid levels and simple renal cyst risk in a nondiabetic population: A nested case-control study

BACKGROUND

Previous studies have found a relationship between hypertension or cardiovascular disease and simple renal cysts (SRCs) in health check-up population, but SRCs incidence is still controversially associated with serum uric acid (SUA) concentration in the nondiabetic participants. In this single-centre nest case-control study, serum uric acid levels were examined in relation to the incidence of SRCs in nondiabetic individuals.

METHOD

Participants who underwent at least two renal ultrasound examinations with an interval of more than 12 months were enrolled. The results of clinical examinations, laboratory tests and abdominal ultrasound tests were recorded for each participant and analysed in this retrospective observation study.

RESULT

A total of 144 control and 144 SRC patients were ultimately confirmed and included in further analysis. Hyperuricaemia (OR 2.846, 95% CI 1.519-5.332, p = 0.001) was significantly correlated with SRC formation according to multivariable analysis. In both the male and female groups, SRC patients had significantly higher serum uric acid levels compared with control subjects. In 54 SRC patients with cyst puncture, the serum uric acid concentration was positively correlated with the uric acid concentration in cyst fluid (r = 0.6144, p < 0.0001). The serum uric acid concentration was positively correlated with the maximum cyst diameter in the SRC patients (r = 0.4531, p < 0.0001).

CONCLUSION

In a nondiabetic population, hyperuricaemia was significantly independently associated with a higher SRCs incidence. In SRC participants with cyst puncture, the SUA level had a significantly positive correlation with the uric acid level in cyst fluid. In SRC patients, the SUA level had a significantly positive correlation with cyst maximum diameter.

Natural history of simple renal cysts: longitudinal CT-based evaluation

PURPOSE

Simple renal cysts are common benign lesions that arise from the renal parenchyma. Cyst growth can lead to confusion as well as concern from patients and referring providers about the need for imaging follow-up or additional evaluation. The purpose of this study was to evaluate the natural history of simple renal cysts and determine the best metric to characterize cyst evolution.

METHODS

222 simple renal cysts in 182 adults (age = 58.4 ± 6.0 years) were longitudinally evaluated on non-contrast CT examinations over a mean interval of 7.5 ± 2.8 years. Axial long axis, surface area, and volume were evaluated at baseline and follow-up CT examinations. Absolute and percent annualized growth rates were computed between CT studies for each parameter.

RESULTS

At baseline CT examinations, mean (± SD) axial long axis, surface area, and volume measurements were 2.5 ± 1.7 cm, 2.5 ± 4.5 cm², and 17.6 ± 52.5 ml, respectively. On follow-up examinations, measurements were 3.4 ± 2.0 cm, 4.2 ± 5.9 cm², and 34.4 ± 92.3 ml, respectively. Significant differences (p < 0.01) were found between baseline and follow-up values for each parameter. The absolute growth rate of each parameter was + 0.1 ± 0.1 cm/year, + 2.1 ± 3.4 cm²/year, and + 2.0 ± 5.6 ml/year, respectively. The percent annualized growth rate for each parameter was +6.5 ± 7.3%/year, +18 ± 24%/year, and +46 ± 100%/year, respectively. Overall, 86% (190/222) of cysts increased in size over time; most notably 78% (174/222) increased by ≥ 6% in volume per year. None of the simple cysts developed septations or solid components on follow-up examinations.

CONCLUSION

The majority of simple renal cysts increase in size over time, which was not associated with the development of complex features. Surface area and volume are the parameters most indicative of cyst growth or regression over time. In patients with enlarging asymptomatic simple renal cysts, no follow-up imaging is indicated.

Evolution of renal cyst to renal carcinoma: a case report and review of literature

BACKGROUND

Renal cyst is a common benign disease which is rare to progress from simple renal cyst to renal cell carcinoma.

CASE PRESENTATION

A 62-year-old woman who suffered a simple renal cyst for over 20 years complained intermittent lumbar in recent 2 years. At her latest admission, the cyst lesion displayed enhancement in the cystic wall by CT scan and cystic to partially solid change by ultrasound, so we did a partial nephrectomy and found that the cystic lesion had become a cyst-solid transition. The pathology turned out to be renal clear cell carcinoma.

CONCLUSIONS

Although the canceration of a renal cyst is a small probability event, patients with a long history of a cyst, especially those with symptoms, need to seek for medical treatment in time, and if necessary, lesion biopsy or resection may be under consideration.

Modeling Neoplastic Growth in Renal Cell Carcinoma and Polycystic Kidney Disease

Renal cell carcinoma (RCC) and autosomal dominant polycystic kidney disease (ADPKD) share several characteristics, including neoplastic cell growth, kidney cysts, and limited therapeutics. As well, both exhibit impaired vasculature and compensatory VEGF activation of angiogenesis. The PI3K/AKT/mTOR and Ras/Raf/ERK pathways play important roles in regulating cystic and tumor cell proliferation and growth. Both RCC and ADPKD result in hypoxia, where HIF-α signaling is activated in response to oxygen deprivation. Primary cilia and altered cell metabolism may play a role in disease progression. Non-coding RNAs may regulate RCC carcinogenesis and ADPKD through their varied effects. Drosophila exhibits remarkable conservation of the pathways involved in RCC and ADPKD. Here, we review the progress towards understanding disease mechanisms, partially overlapping cellular and molecular dysfunctions in RCC and ADPKD and reflect on the potential for the agile Drosophila genetic model to accelerate discovery science, address unresolved mechanistic aspects of these diseases, and perform rapid pharmacological screens.

Partial nephrectomy for a Bosniak IV cystic renal mass mimicking a simple renal cyst adjacent to a solid renal tumor

INTRODUCTION

Renal tumors are often associated with renal cysts. Meanwhile, in some cases there are challenging issues of how to diagnose renal cystic tumors and to decide surgical procedures.

CASE PRESENTATION

A 75-year-old man was referred to our department for a 21-mm tumor by his left kidney. Contrast-enhanced computed tomography showed an intense contrast uptake the tumor, which was adjacent to a 64-mm unilocular renal cyst with no contrasting effects. It was clinically diagnosed as renal cell carcinoma, stage T1aN0M0, and treated with robot-assisted partial nephrectomy, for both the solid tumor and the adjacent cyst. Pathological findings revealed a tumor cell clump within the cyst wall, concurrent with the renal cell carcinoma. The patient has remained free of disease at 1 year after surgery.

CONCLUSION

A partial nephrectomy that includes the entire cyst wall should be considered for renal tumor associated with unilocular renal cyst.

Long-term follow-up study of the malignant transformation potential of the simple renal cysts

Background

We conducted a multi-center study to investigate the prevalence, the malignant transformation potential of the simple renal cysts and the factors that might predict malignancy.

Methods

We defined the simple renal cysts as Bosniak class I & II (including IIF) lesions. In the prevalence study, data from 115,132 ultrasonographies was collected from individuals who participated in a multiphasic health wellness screen. In the natural history and progression study, we retrospectively reviewed 333 participants with simple renal cysts and were followed for at the least 3 years with a mean of 6.3±2.9 years (ranged from 3 to 13 years).

Results

About 7.2% (8,303) of the individuals who participated in the study were found to have at the least one simple renal cyst. The incidence increased with age from 0.6% in the first decade to 28.0% in the eighth or later decade of life. The Bosniak class I lesion accounted for 7,559 or 91.0% of the cysts whereas 744 or 9.0% were class II. A slower growth rate was observed in the older age group. Twenty-four patients (7.2%) had their renal cysts upgraded according to the Bosniak classification. Gender, age, initial cyst size, number of cysts and bi-laterality failed to predict the malignancy tendency.

Conclusions

Most of the cysts discovered were the Bosniak class I and II lesions and they rarely progress further. Treatment for the asymptomatic simple renal cyst is not warranted. Treatment decision-making based on older age or larger initial cyst size should not be recommended.

Radiographic evolution of a simple renal cyst to clear cell renal cell carcinoma in three years

A 53-year-old female was referred for evaluation of a small right renal mass. She had an oncological history of adenocarcinoma of the cervix in 2015. Upon review of her imaging, her right posterior lower-pole lesion demonstrated malignant transformation from a 2.7-cm simple cyst in 2016, to development of a complex cyst with internal vascularity, and ultimately a 1.6 cm, right, lower-pole, exophytic, enhancing, posteriorly located solid renal mass concerning for renal cell carcinoma. The patient opted for surgical removal and underwent a right robotic-assisted laparoscopic partial nephrectomy. Pathology was consistent with a T1a clear cell renal cell carcinoma.