Laparoscopic Nephron-Sparing Surgery in the Management of Angiomyolipoma: A Single Center Experience

Comparisons of the Safety and Effectiveness of Robot-Assisted vs Laparoscopic Partial Nephrectomy for Central Renal Angiomyolipomas: A Propensity Score-Matched Analysis Study

Objective: To compare the safety and effectiveness of robot-assisted partial nephrectomy (RAPN) vs laparoscopic partial nephrectomy (LPN) in the treatment of central renal angiomyolipomas (AMLs). Methods: We retrospectively analyzed the clinical data of 103 patients who were treated with either RAPN or LPN for central AMLs between January 2017 and June 2022. Propensity scores were matched according to sex, age, laterality, body mass index, symptoms, diameter of tumor, location of tumor distribution, R.E.N.A.L score, preoperative hemoglobin, preoperative serum creatinine, preoperative estimated glomerular filtration rate, chronic disease, previous abdominal surgery, preoperative selective arterial embolization, American Society of Anesthesiologists scale, and duration of follow-up, and after matching, perioperative and prognostic data of the two groups were compared. Results: A total of 57 patients underwent RAPN, and 46 patients underwent LPN. Before matching, there were more complex AMLs in the RAPN group, and R.E.N.A.L scores differed between the two groups (10 vs 9, p < 0.001). After matching, the median warm ischemic time in the RAPN group was significantly shorter than that in the LPN group (21.5 minutes vs 28 minutes, p = 0.034), as well as the median time of postoperative mobilization (1 day vs 2 days, p < 0.001). The other indicators were not significantly different between the groups. Conclusions: For central AMLs, both RAPN and LPN were safe and feasible surgical treatments, but RAPN might be associated with shorter warm ischemia time and earlier postoperative mobilization.

Robot-Assisted versus Laparoscopic Partial Nephrectomy for Giant Sporadic Renal Angiomyolipomas of ≥7 cm: A Propensity Score-Matched Analysis

Background

To compare the perioperative and functional outcomes between robot-assisted partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) for giant sporadic renal angiomyolipomas (AMLs) of ≥7 cm.

Materials and Methods

Patients with sporadic renal AMLs of ≥7 cm who underwent RAPN or LPN in the First Affiliated Hospital of Nanchang University between 2015 and 2020 were retrospectively analyzed. Propensity score matching (1 : 1) was performed to adjust for potential baseline confounders. Perioperative and functional outcomes of the RAPN and LPN groups were collected and compared.

Result

After propensity score matching, no statistically significant differences in baseline characteristics were found between the groups (41 vs. 41). Within the matched cohort, the warm ischemia time (WIT) in the RAPN group was significantly shorter than that in the LPN group (21 vs. 27 min, p < 0.001). In addition, the RAPN group was associated with improved postoperative renal function (72.8 vs. 69.8 mL/min/1.73 m², p=0.045). WIT and preoperative renal function are independent predictors of renal function at 6 months postoperatively, and renal score and operation method are independent predictors of WIT.

Conclusion

RAPN and LPN are safe and feasible minimally invasive treatments for sporadic giant renal AMLs, but RAPN is associated with shorter WIT and better postoperative renal functional preservation. WIT and preoperative renal function are independent predictors of renal function at 6 months postoperatively, while the RENAL score and surgical method are independent risk factors to WIT. For giant and complex renal AMLs, RAPN is the first choice when condition permits.

Outcome of simultaneous angioembolization and nephron sparing surgery in large renal angiomyolipomas

AIM

To study the outcome of simultaneous angioembolization and nephron sparing surgery in large renal angiomyolipomas.

MATERIALS AND METHODS

A prospective study of carried out from 2016 to 2019. A total of 15 patients were included in the study with a lesion (angiomyolipoma) more than 10 cm in size, suitable for nephron sparing surgery. The workup of the patients included history, baseline blood investigations, ultrasonography, and CT urography including angiographic films. All the patients were taken up for selective of angioembolization of the feeding vessels of the AML carried out by the interventional radiologist followed by nephron sparing surgery in the same sitting. The short term outcomes studied were warm ischemia time, average blood loss, and length of post-operative hospital stay. The oncological outcome was evaluated by noting the surgical margins of histopathological specimen and functional outcome by assessing the function of the preserved renal parenchyma.

RESULTS

Twelve out of fifteen cases were female. The mean age was 42.25 years. All the patients had lesion more than 10 cm with seven tumors located at the lower pole, four at mid-pole, and four at upper pole. Eight patients had low complexity score on RENAL score (i.e. 4-6), five patients medium complexity score (i.e. 7-9), and two had high complexity score (i.e. ⩾10). Average blood loss was 200 ml, warm ischemia time was 18.46 min and postoperative stay was 3.55 days. All the 15 specimens sent for histopathology were confirmed as AML (angiomyolipomas) with margins free of tumor. Follow up CECT done at 4 months postoperatively revealed functioning residual renal parenchyma with prompt excretion of contrast.

CONCLUSION

Large AML's are also amenable to nephron sparing surgery. However patient should always be warned about the possibility of total nephrectomy. Selective angioembolization helps in reducing the blood supply and risk of torrential bleeding thus facilitates in the removal of the tumor and increasing the chances of nephron sparing surgery.

Evidence-based protocol-led management of renal angiomyolipoma: A review of literature

Renal angiomyolipomas (R-AMLs) are rare benign tumors, which occur sporadically and in association with genetic conditions such as tuberous sclerosis complex (TSC) and lymphangioleiomyomatosis (LAM). The key clinical concern is life-threatening hemorrhage. There is uncertainty about the optimal management strategy for patients with R-AMLs. We aim to review the evidence and provide a protocolled approach for the management of R-AMLs. A literature search of R-AML was conducted using MEDLINE and EMBASE for articles published between January 1990 and March 2020. Patient with TSC and sporadic cases were included. Treatment strategies, including active surveillance, surgery, selective arterial embolization (SAE), ablation, and systemic therapies, were reviewed. Outcomes from contemporary case series of active surveillance, surgery, and SAE were collated. There were no randomized controlled trials on this topic. The retrospective case series reviewed showed that many R-AMLs can be managed safely with active surveillance. Tumor size is the most important predictor of bleeding, and other factors such as rate of growth, women of child-bearing age, aneurysm size, and symptoms should be considered when deciding on prophylactic treatment. There is limited evidence for the traditional 4-cm cutoff for treatment, which may lead to overtreatment. The primary intervention options are SAE and surgery; whereas SAE is a less invasive option, nephron sparing surgery offers a lower risk of recurrence. Both appear to have similar morbidity, and the current evidence does not recommend one over the other in most cases. Thermal ablation has promising results but has only been trialed in small case series. Patients with TSC can be offered mammalian target of rapamycin inhibitors of which everolimus appears to cause the greatest shrinkage of tumors with an acceptable side-effect profile. R-AMLs should be assessed for their risk of bleeding. Low-risk tumors should be treated with active surveillance. High-risk tumors should be treated with SAE or surgery. Systemic treatments are the first-line of treatment for patients with TSC to preserve renal parenchyma.

Contrast-Enhanced CT Texture Analysis for Distinguishing Fat-Poor Renal Angiomyolipoma From Chromophobe Renal Cell Carcinoma

Objective:

To evaluate the value of 2-dimensional (2D) and 3-dimensional (3D) computed tomography texture analysis (CTTA) models in distinguishing fat-poor angiomyolipoma (fpAML) from chromophobe renal cell carcinoma (chRCC).

Methods:

We retrospectively enrolled 32 fpAMLs and 24 chRCCs. Texture features were extracted from 2D and 3D regions of interest in triphasic CT images. The 2D and 3D CTTA models were constructed with the least absolute shrinkage and selection operator algorithm and texture scores were calculated. The diagnostic performance of the 2D and 3D CTTA models was evaluated with respect to calibration, discrimination, and clinical usefulness.

Results:

Of the 177 and 183 texture features extracted from 2D and 3D regions of interest, respectively, 5 2D features and 8 3D features were selected to build 2D and 3D CTTA models. The 2D CTTA model (area under the curve [AUC], 0.811; 95% confidence interval [CI], 0.695-0.927) and the 3D CTTA model (AUC, 0.915; 95% CI, 0.838-0.993) showed good discrimination and calibration (P > .05). There was no significant difference in AUC between the 2 models (P = .093). Decision curve analysis showed the 3D model outperformed the 2D model in terms of clinical usefulness.

Conclusions:

The CTTA models based on contrast-enhanced CT images had a high value in differentiating fpAML from chRCC.

Emergency retroperitoneal laparoscopic partial nephrectomy for ruptured renal angiomyolipomas: a retrospective single-center series of 15 cases

Background

To assess the safety, tumor control and renal function preservation of the emergency retroperitoneal laparoscopic partial nephrectomy (LPN) for ruptured renal angiomyolipoma (AML) and summarize our single-center initial experience.

Methods

We performed a retrospective analysis of 15 patients pathologically confirmed renal AML treated with emergency retroperitoneal LPN between January 2016 and May 2019. The patient demographics, operation time, blood loss, transfusion requirements, complications and other surgical parameters were analyzed. Follow-up was performed by serum creatinine and imaging modalities.

Results

Fifteen patients were performed with emergency LPN with the median age 41.6 years. The mean size of the renal AMLs was 7.8 cm. The mean size of the retroperitoneal hematomas was 8.5 cm. All the emergency surgeries were performed successfully without any conversion to nephrectomy or open surgery. The mean operative time was 101 min. The mean warm ischemia time was 28 min. The mean estimated blood loss was 311 ml. Five patients required intraoperative blood transfusion (33.3%, 5/15). The mean transfused RBC was 4 U (range 2-6 U), and the mean transfused plasma was 200 ml (range 200-400 ml). The mean drainage duration was 3 days (range 2–5 days). The mean postoperative hospitalization was 4.7 days. No patients experienced intraoperative complications. The mean serum creatine was slightly higher after surgery (53.1 vs. 55.9 μmol/L). One patient had postoperative perirenal fluid collection. No patients needed dialysis. No recurrence was observed in the patients at the median follow-up of 24.1 months.

Conclusions

Our initial experience shows that the emergency retroperitoneal LPN is a safe, minimally invasive procedure for emergency patients with ruptured renal AMLs. It could be considered as an effective alternative to renal artery embolization in selected emergency patients.

Comparisons of the safety and effectiveness of robot-assisted versus laparoscopic partial nephrectomy for large angiomyolipomas: a propensity score-matched analysis

OBJECTIVE

To compare the safety and effectiveness of robot-assisted partial nephrectomy (RAPN) versus laparoscopic partial nephrectomy (LPN) for large angiomyolipomas (AMLs).

MATERIALS AND METHODS

We retrospectively evaluated 150 patients who were treated with either RAPN or LPN for large angiomyolipomas from 2014 to 2018. Propensity score matching was performed on age, gender, BMI, Charlson Comorbidity Index, tumour side and size, preoperative eGFR and RENAL score.

RESULTS

In total, 63 and 87 patients underwent RAPNs and LPNs, respectively. There were more large and complex AMLs in the RAPN cohort, with the median tumour maximal diameters and RENAL scores differing between the two groups (8 versus 7 cm and 9 versus 8, P = 0.01). After matching, the median warm ischemic time was significantly shorter in the RAPNs versus the LPNs (17 versus 22 min, P = 0.001). The rate of intraoperative complications in the RAPNs appeared lower than the LPNs (3.2% versus 8.1%). The median postoperative length of stay was significantly shorter in the RAPN cohort than the LPNs (P = 0.001). Twelve months after surgery, RAPNs received a 94.6% renal function prevention; while this was 90.8% in LPNs (P = 0.001). Subgroup analysis indicated that prior selective arterial embolization (SAE) was related to better renal function preservation in the RAPN cohort (P = 0.01). No recurrence occurred in either of the two cohorts.

CONCLUSIONS

RAPN is a safe and effective alternative to LPNs for large AMLs with a shorter warm ischemic time and higher renal preservation rate. Recurrence was equivalent in both RAPNs and LPNs.

Renal angiomyolipoma with tuberous sclerosis complex: How it differs from sporadic angiomyolipoma in both management and care

Renal angiomyolipoma (AML) is the most common benign tumor of the kidney. It consists of blood vessels, smooth muscle and fat components in varying proportions. AML is divided into the sporadic type and tuberous sclerosis complex (TSC)-associated type. TSC-associated AML develops at a younger age and tends to exhibit a much faster growth rate over time than sporadic AML. AMLs are classified as classic AML, fat-poor AML and epithelioid AML. Epithelioid AML, though rare, shows aggressive behavior leading to distant metastasis and mortality. TSC-associated AML is more likely to have an epithelioid component than sporadic AML. Active surveillance is the suggested management for small AML. Clinical intervention is mainly indicated when there is a substantial risk of rupture. Minimally invasive therapies, including partial nephrectomy, transcatheter arterial embolization, and mammalian target of rapamycin (mTOR) inhibitor treatment are employed for patients who require treatment. An updated algorithm for the management of AML is herein described. According to this algorithm, treatment intervention is recommended for TSC-associated AML >3 cm, even in asymptomatic cases. In cases with asymptomatic sporadic AML >4 cm in size or with an intra-tumoral aneurysm of >5 mm, treatment, including transcatheter arterial embolization or partial nephrectomy, is advised. The major complication of AML is intra-tumoral or retroperitoneal hemorrhage due to rupture that may be serious and life threatening. Thus, correct diagnosis, proper observation, and appropriate treatment are very important in the management of renal AML.

Selective Arterial Embolization for Large or Symptomatic Renal Angiomyolipoma: 10 Years of Follow-up

OBJECTIVE

To assess long-term outcome after selective arterial embolization (SAE) as first-line treatment for large or symptomatic AML.

DESIGN, SETTING, AND PARTICIPANTS

Data from a prospectively maintained database on 71 patients who underwent SAE for large or symptomatic AML were reviewed. Patients with sporadic and tuberous-sclerosis-complex (TSC) were included.

OUTCOME MEASUREMENTS

The main endpoints were re-embolization rates, occurrence of clinical events related to AML, size of AML, and renal function.

RESULTS

Thirteen (19.1%) patients reported at least 1 major clinical event. Major complications affected 2 patients (2.9%), both ending in complete loss of renal unit function. Four renal units (5.9%) were eventually treated surgically. The re-embolization rate was 41.1%, with an average time from the initial to a repeat SAE of 2.18 years (range 0.31-10.65 years). The size of the tumor prior to SAE and after 5 and 10 years of follow-up were 8.9 cm (7-12), 6.5 cm (4-7.5), 7 cm (4-7.8), respectively [median (IQR)]. These results are translated to a size reduction of 27% in 10 years follow-up. Patients with TSC had larger tumors on long-term follow-up (77.8 vs 41.3 mm, P = .045). The long-term follow-up estimated average glomerular filtration rate was 81.97 (range 26-196). No patient needed renal replacement therapy, and disease-specific survival was 100%.

CONCLUSIONS

SAE is a safe treatment option for patients with symptomatic or large AML. It represents a minimally invasive intervention with good long-term outcome. SAE may be offered as first-line treatment in most cases, though, it is associated with high retreatment rates.

Ischemia Techniques in Nephron-sparing Surgery: A Systematic Review and Meta-Analysis of Surgical, Oncological, and Functional Outcomes

CONTEXT

The optimal ischemia technique at partial nephrectomy (PN) for renal masses is yet to be determined.

OBJECTIVE

To summarize and analyze the current evidence about surgical, oncological, and functional outcomes after different ischemia techniques (cold, warm, and zero ischemia) at PN.

EVIDENCE ACQUISITION

A computerized systematic literature search was performed by using PubMed (MEDLINE) and Science Direct. Identification and selection of the studies were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria. Outcomes of interest were estimated blood loss (EBL), overall complications, positive surgical margins, local tumor recurrence, and renal function preservation. Meta-analysis and forest-plot diagrams were performed. Overall pooled estimates, together with 95% confidence intervals (CIs), of the incidence of all parameters were obtained using a random effect model (RE-Model) on the log transformed means (MLN), proportion, or standardized mean change, as deemed appropriate.

EVIDENCE SYNTHESIS

One hundred and fifty-six studies were included. No clinically meaningful differences were found in terms of EBL after cold (mean: 215.5; 95% CI: 154.2-276.8m), warm (mean: 201.8; 95% CI: 175.0-228.7ml), or zero (mean: 261.2; 95% CI: 171.0-351.3ml) ischemia technique. Overall, postoperative complications were recorded in 14.1% (95% CI: 6.7-27.4), 11.1% (95% CI: 10.0-12.3), and 9.7% (95% CI: 7.7-12.2) of patients after cold, warm, and zero ischemia (p<0.01), respectively. Positive surgical margins were recorded in 4.8% (95% CI: 1.9-10.9), 4.0% (95% CI: 3.4-4.8), and 5.6% (95% CI: 3.1-9.8) of patients after cold, warm, and zero ischemia (p<0.01), respectively. Local recurrence was recorded in 3.2% (95% CI: 1.9-5.2) and 3.1% (95% CI: 0.7-11.5) of patients after warm and zero ischemia (p<0.01), respectively. The log₂ of estimated glomerular filtration ratio mean changes were-1.37 (95% CI:-3.42 to 0.68),-1.00 (-2.04 to 0.03), and-0.71 (-1.15 to-0.27) ml/min after cold, warm, and zero ischemia, respectively. Low level of evidence, retrospective nature of most of included studies, a high risk of selection bias, and heterogeneity within included studies limited the overall quality of the analysis.

CONCLUSIONS

The effect of ischemia technique at PN is still debatable and subject to confounding by several factors, namely, patients' selection criteria, surgical technique used, and percentage of functional parenchyma spared during surgery. These confounders bias available evidence and were addressed by only a small part of available studies. Unfortunately, the overall quality of literature evidences and the high risk of selection bias limit the possibility of any causal interpretation about the relationship between the ischemia technique used and surgical, oncological, or functional outcomes. Thus, none of the available ischemia technique could be recommended over the other.

PATIENT SUMMARY

The present analysis shows that none of the available ischemia techniques, namely, cold, warm, or zero ischemia, is universally superior to the others, and other factors play a role in the surgical outcome.

Benign Neoplasm of Kidney: Angiomyolipoma

Angiomyolipoma is one of the renal benign neoplasms. The most of the angiomyolipomas are asymptomatic and found incidentally with ultrasound. They are more prevalent in patients with tuberous sclerosis. It is very important to make differential diagnosis from other renal neoplasm such as renal cell carcinoma. Growth rate is higher among pregnant women suggest that the hormones may play a role in the stimulation of angiomyolipoma. The most common serious presentation is rupture and hemorrhage, and sometimes it can lead to shock. Adequate diagnosis, treatment, and follow-up are very important in the face of renal angiomyolipoma.

Retroperitoneal laparoscopic nephron sparing surgery for large renal angiomyolipoma: Our technique and experience. A case series of 41 patients

OBJECTIVES

To introduce a 'kidney priority' strategy in treating large renal angiomyolipoma (RAML) with retroperitoneal laparoscopic nephron sparing surgery (RLNSS).

PATIENTS AND METHODS

From 2010 to 2017, 41 patients with large RAML underwent RLNSS. Distinguished from the standard practice, the kidney was preferentially mobilized and separated from the RAML. Subsequently, it was reconstructed. Finally, the RAML was resected from the perinephric fat. The perioperative variables, surgical technique and complications were reviewed. Patients were followed up with ultrasonography and computed tomography.

RESULTS

RLNSS was successfully performed in 35 patients with four conversions to open surgery and two conversions to nephrectomy, respectively. Eight patients required an intraoperative blood transfusion. Seven patients experienced postoperative complications, including one wound infection, one urinary tract infection, one pneumonia, one urinary fistula and three hemorrhage. The median operation time was 167min (range, 95-285min), the median warm ischemia time was 21 min (range, 0-40 min), and the median estimated blood loss was 200 ml (range, 30-2500 ml). The median postoperative stay was 6.5 days (range, 3-11 days). Angiomyolipoma was confirmed pathologically in all patients. Median serum creatine increased after surgery, from 0.7 mg/dl (range, 0.4-1.1 mg/dl) preoperatively to 0.8 mg/dL (range, 0.5-1.4 mg/dl) postoperatively (P = 0.016). No patient required dialysis, and no recurrence was observed after a median follow-up of 35 months (range, 3-85 months).

CONCLUSIONS

RLNSS is a safe, feasible, effective and minimally invasive procedure to manage large RAML in selected patients.

The Risks of Renal Angiomyolipoma: Reviewing the Evidence

Renal angiomyolipoma (RAML), though a rare benign tumor, may impose a significant morbidity or even mortality due to its unique characteristics and the complications subsequent to its treatment. The classic tumor variant is composed of smooth muscular, vascular, and fatty components. The most straightforward diagnosis is when the fat component is abundant and gives a characteristic appearance on different imaging studies. In fat-poor lesions, however, the diagnosis is difficult and presumed a renal cell carcinoma. Yet, some variants of RAML, though rare, express an aggressive behavior leading to metastasis and mortality. The challenge lies in the early detection of benign variants and identifying aggressive lesions for proper management. Another challenge is when the vascular tissue component predominates and poses a risk of hemorrhage that may extend to the retroperitoneum in a massive life-threatening condition. The predicament here is to identify the characteristics of tumors at risk of bleeding and provide a prophylactic treatment. According to the clinical presentation, different treatment modalities, prophylactic or therapeutic, are available that span the spectrum of observation, embolization, or surgery. Renal impairment may result from extensive tumor burden or as a complication of the management itself. Improvement of diagnostic techniques, super-selective embolization, nephron-sparing surgery, and late treatment with the mammalian target of rapamycin inhibitors have provided more effective and safe management strategies. In this review, we examine the evidence pertaining to the risks imposed by RAML to the patients and identify merits and hazards associated with different treatment modalities.

Cryoablation of Renal Angiomyolipoma: An Evaluation of Safety and Efficacy

BACKGROUND

Small series have reported that cryoablation (CA) is a safe and feasible minimally invasive nephron-sparing alternative for the treatment of renal angiomyolipomas (renal AMLs). The aim of the present study was to investigate the safety and efficacy of CA in patients with renal AML.

MATERIALS AND METHODS

A retrospective review of 19 renal AML lesions treated with CA at Aarhus University Hospital, Denmark, over a 5-year period.

RESULTS

The treatment was performed as laparoscopy-assisted CA on 7 lesions, and in the remaining 12 lesions CA was performed as a percutaneous ultrasound-guided CA. The mean patient age was 46 years [interquartile range (IQR) 30] and the mean tumor volume was 50.1 cm³ (IQR 53.3). In all cases, the procedure was effectively conducted with no conversion to open surgery, and no major complications were experienced. The mean follow-up time was 25 months (IQR 13). Mean maximum tumor volume was reduced from 50.1 cm³ (IQR 53.3) to 12.2 cm³ (IQR 14.1), p = 0.05. No patients presented with retroperitoneal hemorrhage or recurrence during follow-up.

CONCLUSION

Treating renal AMLs with CA appears to be a safe and effective nephron-sparing approach and could be a valuable alternative to other treatment modalities. The low complication rate, absence of retreatment and a good preservation of renal function might allow treatment of even subclinical renal AMLs to minimize the risk of potentially life-threatening hemorrhage.

Microsatellite analysis for differentiating the origin of renal angiomyolipoma and involved regional lymph node

Renal angiomyolipoma (AML) with the regional lymph node (LN) involved leads to a question of metastasis versus multicentric origin when their histology are similar. As the genomic instability is a common feature of cancer, we hypothesized that independently arising neoplasms in an individual patient would exhibit measurable genomic variation, facilitating the discrimination of tumor lineage and relatedness. Our study enrolled 12 patients who were diagnosed with nodal-involved renal AML at West China Hospital. Genomic DNA from kidney and lymph node lesion from individuals was analyzed through PCR-based analysis which using six microsatellite markers to identify discordant allelic variation. The results showed all 12 patients underwent surgical treatment and none suffered local recurrence or distant metastasis during the follow-up. Ten patients of the included cases showed a consistent trend that all corresponding to six microsatellite markers were detected in DNA from renal AMLs but were reduced or not observed in DNA from the paired LN. With this technique, a possible lineage relationship cannot be excluded between renal AMLs and LN. Thus when enlarged LN were found in images, active surveillance should be taken into consider; if enlarged LN were found intraoperatively, LN resection might be necessary to demonstrate their pathological nature.

Laparoscopic Retroperitoneal Nephron-Sparing Surgery Without Renal Artery Clamping with Preoperative Selective Arterial Embolization for Management of Right Renal Angiomyolipoma of Diameter 10 cm: A Case Report

A 38-year-old female without the tuberous sclerosis complex was diagnosed with right renal angiomyolipoma of 10 cm in diameter. She underwent laparoscopic retroperitoneal nephron-sparing surgery without renal artery clamping with preoperative selective arterial embolization to avoid a significant risk of hemorrhage and the damage of the renal function during nephron-sparing surgery. The tumor was resected completely. The time taken to complete the procedure was 4 hours 11 minutes and blood loss was 780 mL. She was transfused 400 mL of autologous blood.

Partial Nephrectomy for a Massive Sporadic Renal Angiomyolipoma: Case Report and Review of the Literature

Introduction. Angiomyolipomas are the most common benign tumor of the kidney, associated with Tuberous Sclerosis in 20% of cases and arising sporadically in 80% of cases. Renal angiomyolipomas are neoplasms of mesenchymal origin with varying proportions of vasculature, smooth muscle spindle cells, and adipocytes, making management of such neoplasms a challenging endeavor. Possible management options include partial or radical nephrectomy and segmental renal artery embolization. Case Presentation. A 61-year-old woman admitted for a large retroperitoneal hemorrhage was discovered to have a giant, sporadic, 3818.3 g, 30.0 × 26.5 × 18.0 cm left perinephric angiomyolipoma. Given her hemodynamic instability upon presentation, she underwent segmental arterial embolization, followed by an open left partial nephrectomy. Ten-month follow-up revealed no noticeable loss of renal function. Discussion. Literature review revealed occasional renal angiomyolipomas of comparable size, with all angiomyolipomas larger than this requiring treatment with radical nephrectomy. Conclusion. We show that nephron-sparing surgery may be considered in the treatment of even the largest of renal angiomyolipomas.

Robotic Partial Nephrectomy in the Treatment of Renal Angiomyolipoma

PURPOSE

To present the experience and efficacy of Robotic Partial Nephrectomy (RPN) for the management of renal angiomyolipomas (AMLs) with regard to renal function preservation and perioperative outcomes.

PATIENTS AND METHODS

We retrospectively searched our RPN database for pathologically confirmed renal AML patients between 2006 and 2014. Clinical presentation, perioperative complications, and postoperative outcomes of the patients were analyzed. Preoperative imaging findings were reviewed to examine their ability to predict pathology of AML.

RESULTS

From 1005 RPN performed in our center during the study period, 53 patients met our inclusion criteria. The mean age at presentation was 54.1 (± 13) years, and 42 (79.2%) patients were female. Median tumor size was 2.8 (interquartile range [IQR], 1.8-4.6) cm. The indication for RPN was suspicious radiologic features for malignancy in 42 (79.2%) patients and acute retroperitoneal hemorrhage risk and pain in 11 (20.8%) patients who were found to have AML according to preoperative imaging. Mean estimated blood loss was 198 (± 194) mL, and 5 (9.4%) patients required blood transfusion. Postoperative complications occurred in 8 (15%) patients. Median estimated glomerular filtration rate within the latest follow-up was 86.9 (IQR, 69.7-100.1) mL/minute/1.73 m(2) with a median of 91% (IQR, 80.4-103) preservation. None of patients developed urinary fistula or pseudoaneurysm requiring second intervention. No local recurrences occurred with a median follow-up of 7 (IQR, 1-17) months.

CONCLUSION

Given the low complication rate and preservation of renal function after RPN for AML, it can be considered a reliable method for AML treatment. The majority of AMLs were not suspected based on preoperative imaging. Further diagnostic methods are needed to differentiate benign from malignant lesions.

Update on the Diagnosis and Management of Renal Angiomyolipoma

PURPOSE

Advances in minimally invasive therapies and novel targeted chemotherapeutics have provided a breadth of options for the management of renal masses. Management of renal angiomyolipoma has not been reviewed in a comprehensive fashion in more than a decade. We provide an updated review of the current diagnosis and management strategies for renal angiomyolipoma.

MATERIALS AND METHODS

We conducted a PubMed(®) search of all available literature for renal or kidney angiomyolipoma. Further sources were identified in the reference lists of identified articles. We specifically reviewed case series of partial nephrectomy, selective arterial embolization and ablative therapies as well as trials of mTOR inhibitors for angiomyolipoma from 1999 to 2014.

RESULTS

Renal angiomyolipoma is an uncommon benign renal tumor. Although associated with tuberous sclerosis complex, these tumors occur sporadically. Risk of life threatening hemorrhage is the main clinical concern. Due to the fat content, angiomyolipomas are generally readily identifiable on computerized tomography and magnetic resonance imaging. However, fat poor angiomyolipoma can present a diagnostic challenge. Novel research suggests that various strategies using magnetic resonance imaging, including chemical shift magnetic resonance imaging, have the potential to differentiate fat poor angiomyolipoma from renal cell carcinoma. Active surveillance is the accepted management for small asymptomatic masses. Generally, symptomatic masses and masses greater than 4 cm should be treated. However, other relative indications may apply. Options for treatment have traditionally included radical and partial nephrectomy, selective arterial embolization and ablative therapies, including cryoablation and radio frequency ablation, all of which we review and update. We also review recent advances in the medical treatment of patients with tuberous sclerosis complex associated angiomyolipomas with mTOR inhibitors. Specifically trials of everolimus for patients with tuberous sclerosis complex suggest that this agent may be safe and effective in treating angiomyolipoma tumor burden. A schema for the suggested management of renal angiomyolipoma is provided.

CONCLUSIONS

Appropriately selected cases of renal angiomyolipoma can be managed by active surveillance. For those patients requiring treatment nephron sparing approaches, including partial nephrectomy and selective arterial embolization, are preferred options. For those with tuberous sclerosis complex mTOR inhibitors may represent a viable approach to control tumor burden while conserving renal parenchyma.

Evaluation of split renal function before and after renal arterial embolization for angiomyolipoma using absolute ethanol

PURPOSE

Transcatheter arterial embolization (TAE) with absolute ethanol is widely accepted as a therapeutic procedure for renal angiomyolipoma (AML). We aim to evaluate the split renal function before and after AE for renal AML by using 99m-technetium (99mTc)-mercaptoacetyltriglycine 3 (MAG3) renography.

METHODS

This study was approved by the Institutional Review Board. The study population comprised 11 renal AML patients (three males, eight females, age 55.1 ± 13.8 years, AML in eight right and three left kidneys) who received unilateral renal TAE with absolute ethanol from April 2002 to January 2013. Blood renal function (i.e. serum creatinine and estimated glomerular filtration rate [eGFR] and split effective renal plasma flow [ERPF]) calculated on 99mTc-MAG3 renography was compared before and within 1 week after renal AE. Statistical analysis was calculated using Wilcoxon signed-ranked test.

RESULTS

TAE for renal AML was technically successful in all patients. Serum creatinine and eGFR did not change before and after TAE. ERPF on the embolized kidney did not change before (127.3 ± 60.8 ml/min) and after (127.6 ± 47.4 ml/min) TAE (p = 0.9726). ERPF on the nonembolized kidney showed a statistically significant increase before (152.5 ± 46.8 ml/min) and within 1 week after (169.1 ± 41.5 ml/min) TAE (p = 0.0093 and p < 0.05, respectively).

CONCLUSION

TAE for renal AML may not induce renal dysfunction on the embolized kidney and may immediately increase the renal blood flow of the nonembolized kidney.

Laparoscopic aspiration for central renal angiomyolipoma: a novel technique based on single-center initial experience

OBJECTIVE

To report on the novel technique of laparoscopic aspiration for central renal angiomyolipoma (RAML) in a series of patients treated in our institution and summarize our single-center initial experience.

METHODS

We retrospectively reviewed the clinical data of 10 patients (4 men and 6 women) with pathologically confirmed central RAML who underwent laparoscopic aspiration between August 2010 and May 2012. Indications for surgical intervention included 8 (80%) tumors of >4 cm and 2 (20%) symptomatic RAMLs. Patient demographics, intraoperative variables, and postoperative outcomes were reported and analyzed. Follow-up was performed by serum creatinine and imaging techniques.

RESULTS

All patients were diagnosed with sporadic central RAML. None was affected by tuberous sclerosis. All operations were performed successfully by laparoscopic aspiration without conversion to partial nephrectomy, enucleation, or even open surgery. One complication of perirenal fluid collection occurred but finally recovered only with conservative treatment. No other complication or transfusion was observed. The mean tumor size was 5.1 cm (range 3.2-7.7 cm). The mean operative time was 92.1 minutes (range 67-140). The mean warm ischemia time was 27.5 minutes (range 20-30). The mean estimated blood loss was 53.5 mL (range 10-150). The mean retroperitoneal drainage was 2.3 days (range 1-3). The mean postoperative hospital stay was 4.3 days (range 3-8). The level of serum creatinine were all within normal limits with mean preoperative and postoperative 0.85 mg/dL (range 0.55-1.07) and 1.11 mg/dL (range 0.71-1.26), respectively. No recurrence or new lesions occurred in these patients at a mean follow-up of 7.7 months.

CONCLUSION

Our initial experience suggests that the novel technique of laparoscopic aspiration is a feasible, safe, and effective minimally invasive procedure for the treatment of RAML, especially the central RAML. It can be a nephron-sparing alternative and recommended in well-selected patients that might prove to be safer, with equal efficacy, and should be further explored.

Radiofrequency ablation (RFA) therapy for renal angiomyolipoma (AML): an alternative to angio-embolization and nephron-sparing surgery

OBJECTIVES

To show that radiofrequency ablation (RFA) is safe and effective treatment for renal angiomyolipoma (AML). Current treatments to reduce the risk of haemorrhage include tumour extirpation, angio-embolization, or ablative therapy.

PATIENTS AND METHODS

Review of our prospective database revealed 15 patients with intraoperative biopsy confirmed renal AML undergoing RFA from February 2002 to March 2010. Patients underwent either laparoscopic or computed tomography (CT)-guided percutaneous RFA using either the Cool-tip™ (Covidien, Inc. Boulder, CO, USA) or RITA™ (Angiodynamics(®), Latham, NY, USA) RFA probe. CT at 1 month, 6 months, 1 year, and annually thereafter.

RESULTS

In all, two male and 13 female patients with seven left-sided and eight right-sided tumours with a mean (range) size of 2.6 (1.0-3.7) cm underwent laparoscopic (five) or CT-guided (10) RFA. No intraoperative complications occurred. Minor complications included transient haematuria and intercostals nerve transection. Surgical complications included pneumonia and myocardial infarction. There was no radiographic evidence of persistent AML (CT enhancement) at a mean follow-up of 21 months.

CONCLUSIONS

The haemostatic effect of RFA allows renal lesions suspicious for AML to be treated without bleeding complications. Avoids surgical risk of extirpation or embolization. RFA for renal AML is safe and effective.