Angiomyolipoma Research Articles

Active Surveillance for Renal Angiomyolipoma Less Than 4 Centimeters: A Systematic Review of Cohort Studies.

The aim of this review is to evaluate the current evidence regarding the best management in terms of active surveillance of angiomyolipoma (AML) cases less than 4 cm, particularly the optimal timing of active surveillance. In addition, we aimed to describe their initial size, clinical presentation, and growth rates. The present systematic review included prospective and retrospective studies that evaluated and followed up patients with AML through active surveillance. Studies were retrieved through an online bibliographic search of the Medline database via PubMed, SCOPUS, Web of Science, and Cochrane Library from their inception to January 2022. Seven studies were included in the present systematic review. Concerning the active surveillance protocol, only four studies describe the frequency of active surveillance and the utilized imaging modality. Some studies followed up lesions by ultrasound annually for two to five years, while other studies followed-up patients twice for the first year, then annually for a median follow-up period of 49 (9-89) months. The used modalities were ultrasound, CT, and magnetic resonance imaging (MRI). Notably, the incidence of spontaneous bleeding was consistent across the included studies (ranging from 2.3 - 3.1%), except for one study which showed an incidence rate of 15.3%. In terms of the need for active treatment, the rate of active treatment was slightly higher in some studies than the others. However, this variation could not be considered clinically relevant to favor one surveillance strategy over the other. We concluded that active surveillance is the first line of management in all small asymptomatic ALMs. ALMs less than 2 cm do not require active surveillance. The current published literature suggested that active surveillance for two years may provide the same benefits as a five-year surveillance strategy, with fewer radiation hazards and less socioeconomic burden.

Evaluation of safety and effectiveness of cryoablation in the treatment of renal angiomyolipoma related to tuberous sclerosis complex: The Cryo-TSC study.

TPS397 Background: Tuberous sclerosis complex (TSC) is an autosomal dominant inherited disease that causes benign tumors called hamartoma all over the body as well as neuropsychiatric symptoms such as epilepsy. One-third of patients have a family history of the disease, but the remaining two-thirds are solitary cases and are caused by newly arising mutations. The TSC1 gene on chromosome 9 and TSC2 on chromosome 16 have been identified as the causative genes. Approximately 60%–80% of patients with TSC have renal lesions, and angiomyolipoma (AML) occurs bilaterally. The frequency of TSC-associated AML (TSC-AML) increases with age, reaching 60%–80% in adults, and the rate of death from renal disease increases with age in TSC patients. The current standard of care for AML is arterial embolization or surgery (partial nephrectomy or nephrectomy), but TSC is a hereditary disease and AMLs occur one after another with age. Repeated surgical procedures are technically difficult, and arterial embolization has a high recurrence rate. Under these circumstances, an mTOR inhibitor, everolimus, has shown a marked reduction of TSC-AML and is widely used. However, everolimus must be administered permanently because AML re-occurs after discontinuation of everolimus. Cryotherapy has been used as a treatment for renal tumors, and there have been some reports of cryotherapy for solitary AML, but the safety and efficacy of cryotherapy for TSC-AML have not been established. Therefore, we planned this study to establish the safety and efficacy of cryotherapy for TSC-AML. Methods: This is an open-label, single-arm, phase II study to evaluate the safety and efficacy of cryotherapy for TSC-AML of 4 cm or less in patients with 16 years of age or older. The exclusion criteria are an inability to withdraw from mTOR inhibitor and failure to maintain rest during cryotherapy. mTOR inhibitor medication should be withdrawn at least 7 days prior to cryotherapy and discontinued during the study period. Cryotherapy will be performed using Cryohit (GALIL MEDICAL LTD, Israel). Safety will be assessed at 1, 2, 6, and 9 months after cryotherapy, and efficacy will be assessed at 3 and 9 months after cryotherapy. The efficacy of cryotherapy will be evaluated according to modified RECIST or RECIST criteria. The primary endpoint will be the disease control rate of AML treated with cryotherapy, and secondary endpoints will be the overall response rate, safety, renal function, quality of life, and whether additional treatment is required. Clinical trial information: jRCTs072200039.

Uterine angiomyolipoma: A case report of an unusual entity

Angiomyolipoma (AML) is a rare benign mesenchymal neoplasm composed of a variable mixture of smooth muscle cells, adipose tissue and anomalous blood vessels. It belongs to the family of perivascular epithelioid cell tumors (PEComas). It is quite common in kidney but is rare at the extrarenal sites. In the uterus, only a few cases have been reported. We describe a case of uterine AML without evidence of tuberous sclerosis (TS). It was clinicoradiologically mistaken for fibroid. The clinical presentation of uterine AML is similar to more common uterine leiomyomas. AML can be suspected on the imaging but histopathology establishes a confirmed diagnosis. The case is presented for its rarity and likelihood of mistaking it for some other mesenchymal tumors. Overall, just 36 cases of Uterine AML have been reported in the English literature prior to this and this is only the second Indian case.

Renal Cell Carcinoma Subtypes and Associated Renal Malignancies: A Pictorial Review—Part II

In this second article in this series, we present a pictorial review of common renal neoplasms and renal malignancy mimics, including urothelial carcinoma, liposarcoma, oncocytoma, renal pseudotumors, and renal metastases. Renal cell carcinoma (RCC) subtypes and their respective radiologic findings were discussed in Part I of this series. Principles of management of select RCC subtypes and other renal neoplasms, including urothelial carcinoma and angiomyolipoma (AML), will be discussed. Management of solitary renal masses via active surveillance (AS) or surgical intervention and the indications for renal mass biopsy as part of the diagnostic workup will also be reviewed.

Genotype-phenotype correlation of renal lesions in the tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disease caused by loss-of-function mutations in either of two tumor suppressor genes, TSC1 and TSC2. These mutations lead to the growth of benign tumors and hamartomas in many organs, including those of the central nervous system, the skin, and the kidneys. To investigate the genotype-phenotype correlation, we performed sequence analysis of the TSC1/2 genes using next-generation sequencing. We classified 30 patients with TSC whose pathogenic variants were identified into two groups: those with mutations producing premature termination codons (PTCs) and those with missense mutations. Then, we compared the phenotypes between the two groups. Patients with a PTC were significantly more likely to manifest the major symptoms of the diagnostic criteria than those without a PTC (P = 0.035). The frequencies of subependymal nodules (P = 0.026), cortical tubers (P = 0.026), and renal cysts (P = 0.026) were significantly higher in PTC-containing variants than in cases without a PTC. When the analyses were limited to renal angiomyolipoma (AML) cases with TSC2 mutations, there was no difference in tumor size between cases with and without a PTC. However, the cases with a PTC showed a trend toward disease onset at a younger age and multiple tumors, and bilateral disease was observed in their AML lesions. TSC patients with PTC-producing mutations might potentially manifest more severe TSC phenotypes than those with missense mutations. A larger-scale study with appropriate samples deserves further investigation.

Individualized everolimus treatment for tuberous sclerosis-related angiomyolipoma promotes treatment adherence and response.

ABSTRACTBackgroundEverolimus is a potential alternative to embolization and nephrectomy for managing tuberous sclerosis complex (TSC)-associated renal angiomyolipoma (AML). In 2016, National Health Service England approved its use through regional centres for renal AML ≥30 mm showing interval growth. Evidence of lesion stabilization or reduction after 6 months is mandated for continuation of long-term treatment.MethodsFrom November 2016 to June 2021, all potentially eligible adult TSC patients with AML across Yorkshire and Humber were referred for assessment and monitoring. Eligible patients underwent baseline renal magnetic resonance imaging (MRI) assessment and a follow-up MRI scan after 6 months on everolimus. Dose titration was guided by trough levels and lesion responsiveness using a new 3D MRI volumetric protocol.ResultsOf 28 patients commencing treatment, 19 tolerated everolimus for >3 months. Overall, 11 patients (40%) discontinued treatment, mostly due to recurrent infections (42%) and allergic reactions (25%). Sixty-eight percent required dose adjustments from the initiating dose (10 mg) due to sub-optimal trough levels (38%), minimal AML response (15%) or adverse events (47%). 3D volumetric assessment confirmed a reduction in AML volume of a pre-selected index lesion in all treatment-naïve cases (n = 14), showing superiority over 2D measurements of lesion diameter.ConclusionIn this cohort, everolimus promoted AML regression in all patients who tolerated the drug for >6 months with stabilization observed over 3 years. Trough levels enabled individual dose titration to maximize responsiveness and minimize side effects. The use of 3D MRI assessment of lesion volume was superior to 2D measurements of lesion diameter in monitoring treatment response.

Use of Microballoon Catheter in Transarterial Ethanol Embolization of Renal Angiomyolipoma: A Retrospective Comparative Study with Historical Control?

Purpose: To clarify the utility of microballoon catheter in renal arterial ethanol embolization of renal angiomyolipoma (AML). Material and Methods: A total of 20 patients (15 women, 5 men) with median age of 45 years (39-60 years) underwent embolization to treat 22 AMLs. A mixture of ethanol and iodized oil was injected into the feeding arteries of 13 tumors using balloon occlusion (the balloon embolization group) with a microballoon catheter and 9 tumors without using balloon occlusion (the non-balloon embolization group). Changes in the maximum tumor diameter, tumor volume, and adverse events were evaluated. Result: The median baseline maximum tumor diameters and volumes were 6.3 cm and 61.4 cm3 in the balloon embolization group, and 4.6 cm and 40.1 cm3 in the non-balloon embolization group, respectively. Tumor enhancement disappeared on postembolization angiography in all cases. All tumors shrunk after embolization. There were no statistically significant differences in the percent decrease in the maximum tumor diameter and volume at 10-12 month between balloon occlusion group (31.5% and 67.9%) and control group (34.8% and 62.6%). Fever was significantly more frequent when balloon occlusion was used: 38% vs. 0% (p = 0.03). No major complication was observed in either patient group. Conclusions: Balloon occlusion may not affect tumor shrinkage when embolizing AMLs with a mixture of ethanol and lipiodol.

Common Subtype of Small Renal Mass MR Imaging Characterisation: A Medical Center Experience in Taiwan

PurposeMany studies have shown that multiparametric magnetic resonance imaging (MRI) may be helpful for differentiating malignant renal cell carcinomas (RCCs) from benign lesions. However, the key imaging characteristics that differ between malignant and benign tumors still require further discussion.MethodsWe analyzed 60 adult patients diagnosed with 72 small renal masses (SRMs) who received preoperative MRI from 2014 to 2019 at a hospital in Taiwan. The MRI features included conventional MRI parameters, diffusion-weighted imaging (DWI) data, and dynamic contrast-enhanced (DCE) patterns, which were documented and compared among the four common subtypes: clear cell RCC (ccRCC), papillary RCC (pRCC), angiomyolipoma (AML) and other types of RCC. The apparent diffusion coefficient (ADC) values of high- and low-grade RCCs were also analyzed.ResultsThe results show that ccRCC had higher T2-weighted signal intensity than the other three subgroups, a higher arterial wash-in index (AWI) and ADC value than AML and pRCC, and manifested a plateau (n = 9, 25%) or washout (n = 27, 75%) enhancement pattern. AMLs exhibited more intravoxel fat than the other three subtype groups, and half of the AMLs (6 in 12) contained bulk fat. pRCC demonstrated a more progressive (n = 3, 60%) enhancement pattern than the other three subgroups. The ADC value of high-grade RCCs was significantly lower than that of low-grade RCCs.ConclusionThese findings may indicate that multiparametric MRI is useful in differentiating among four common pathological types of SRMs, and the ADC value may be helpful in evaluating the histological grade of malignancy.

New Trends and Evidence for the Management of Renal Angiomyolipoma: A Comprehensive Narrative Review of the Literature.

Treatment of renal angiomyolipoma (AML) seeks to reduce related complications and preserve kidney function. The purpose of this article was to perform an updated literature review on the diagnosis, therapeutic options, and criteria for invasive intervention in patients with renal AML. Computerized tomography is the standard diagnostic method for renal AML, while definitive diagnosis is made by histopathology. The management of choice in most cases is active surveillance (AS), with a clinical and imaging follow-up protocol. In high-risk cases, therapeutic management should be considered, with alternatives such as selective arterial embolization (SAE), nephron-sparing surgery (NSS), and mTOR inhibitors in selected patients. Renal AML in women of childbearing age, those with growth >0.25 cm/year, intralesional aneurysms >5 mm, and clinically significant symptoms may qualify for active treatment. Despite the limitations derived from the available evidence, it is possible to consider SAE, NSS, and the use of mTOR inhibitors as management alternatives for selected patients.

DIAGNOSTIC VALUE OF MULTI-SLICE CT SCAN FOR RENAL ANGIO- MYOLIPOMA DETECTION: A CASE REPORT

Background: Angiomyolipoma (AML) is a rare solid benign tumor that occurs at many sites, more commonly in the kidney, which arises from either the renal pelvis or the sinus, also referred to as renal hamartoma. AML is composed of blood vessels, smooth muscle cells, and fat hence the name. They are seen 80-90% as isolated lesions that occur sporadically and seen 25-50% of patients with tuberous sclerosis. AML may hard to be distinguished from renal cell carcinoma because of its presentation as enlarged lump. Computed tomography may help to diagnose AML. To get a definite diagnosis of AML, excision and histopathological examination is recommended in symptomatic patients, especially to prevent rupture hemorrhage. Objective: The purpose of this study was to evaluate multi-slice computed tomography with contrast in a male patient aged 49 years with Angiomyolipoma Case description: We herein present a case of renal AML in a 49 years old male patient, who presented with left flank pain for ~1 year. He has no history of hematuria and dysuria and tuberous sclerosis. Multi-slice computed tomography with contrast demonstrates a hypodense inhomogenous mass measuring 11x9,3 cm in the upper pole of the left kidney, hypertrophy of the left kidney, and hump sign of left kidney. At the later date, the patient underwent total left nephrectomy at another hospital and the postoperative histopathological examination confirmed the lesion as an AML. Conclusion: Angiomyolipoma is a rare benign tumor which usually occurs in the kidney that can be confused with malignant tumor. Ultrasonography and computed tomography can help to diagnose AML. The symptomatic patient requires surgical intervention.

Renal AML Surgically Treated 33 Cases

BACKGROUND: Renal angiomyolipoma (RAML) is a rare benign neoplasm with a prevalence varying between 0.2% and 0.6% and a strong female predilection. They occur as sporadic, isolated entities in 80% of cases. The remaining 20% of angiomyolipomas (AMLs) develop in association with tuberous sclerosis complex or pulmonary lymphangioleiomyomatosis. AIM: We describe our 10-year experience with AML and discuss the treatment strategies employed at our center. METHODS: The medical records of all 33 patients with pathologically confirmed RAML treated either by nephrectomy or nephron-sparing surgery at our center over 10 years were reviewed for patient age and sex, tumor location and size, association with TBS. RESULTS: There were 28 females (84.8%) and 5 males (15.2%) with a median age that was 52 (range 22–74) years at the time of surgery. Thirty patients (90.9%) had sporadic isolated AML, and 3 patients (9.1%) had AML with TBS. The tumor was in the right kidney in 15 (45.5%) patients, in the left kidney in 17 (51.5%) patients, and bilateral in only 1 patient (3%) who was diagnosed with TBS. At presentation, flank pain was the main symptom in 23 patients (69.7%). CONCLUSIONS: Surgical resection of RAML provides short-term symptomatic relieve and long-term survival.

Pulmonary lymphangioleiomyomatosis with an associated giant renal angiomyolipoma.

Pulmonary lymphangioleiomyomatosis (LAM), a rare, progressive disease predominantly affecting the lungs of women of reproductive age, is often associated with renal angiomyolipoma (AML). We report the case of a 29-year-old female patient who presented to our obstetrics department at 37 weeks’ gestation, complaining of abdominal pain, and constipation. Ultrasound noted a viable singleton with a large left-sided abdominal mass. After undergoing a caesarean section, she was referred to our urology department to assess her flank mass further. Computed tomography demonstrated a large, exophytic left renal mass measuring 22 cm x 16 cm x 13 cm, suggestive of an AML and numerous bilateral pulmonary cysts. A diagnosis of LAM and associated unilateral giant renal AML was made. As soon as she had fully recovered from her caesarean section, we removed the huge AML via a standard left-sided open nephrectomy without incident. We report this rare case of giant AML associated with LAM and review the literature about the association of these two conditions.

Contribution of diffusion weighted MRI to the differential diagnosis of renal masses

ntroduction and aim. We aimed to assess the usefulness of diffusion weighted imaging (DWI) and apparent diffusion coefficients (ADCs) for characterizing renal masses. Material and method. In this retrospective study we measured the ADC values of renal masses at b=0, b=500 and b=1000. Measurements were made by placing a circular region of interest with a diameter of 1 cm.ADC values from normal renal parenchyma were taken to define the ADC and to compare with the ADC values of the lesions. Results. A total of 72 lesions of 54 patients were included.40 of the masses were benign and 32 were malignant. The ADC values of benign lesions at both b values were significantly higher than malignant lesions. We found the lowest values in angiomyolipomas (AMLs) and oncocytomas and the highest values in Bosniac type I cysts. Similarities was found between the ADC values of some AMLs and the RCCs. In terms of statistical results, the inclusion of AMLs in the analysis did not significantly affect the difference between malignant and benign lesions. Conclusion. In our study, the ADC values of benign renal masses were higher than those of normal renal parenchyme, which is higher than those of malignant renal masses.The lowest ADC values were observed in AMLs and oncocytomas.

The quantitative evaluation of contrast-enhanced ultrasound in the differentiation of small renal cell carcinoma subtypes and angiomyolipoma.

Contrast-enhanced ultrasound (CEUS) has been widely used for renal lesion diagnosis and differential diagnosis. However, qualitative analysis of CEUS is subject to examinations with low reproducibility. This study aims to investigate the diagnostic value of CEUS quantitative parameters in differentiating small renal cell carcinoma (RCC) subtypes and angiomyolipoma (AML). A retrospective analysis was performed on 97 cases of a small renal mass undergoing a CEUS before a radical or partial nephrectomy procedure. A region of interest (ROI) was placed in the tumor's maximum enhanced region (ROImax) as much as possible, and adjacent renal cortex (ROIrefer) was selected from normal renal tissue around a mass of the same depth. The time-intensity curve (TIC) was used to analyze the ROImax and the ROIrefer of the tumors quantitatively. Then the parameters of the ROImax and the ROIrefer, including the differences between the parameters of the ROImax and the ROIrefer, were analyzed statistically. In RCC and clear cell renal cell carcinoma (ccRCC), the peak intensity (PI), slope (SL), area under the curve (AUC), area under the wash-in curve (AWI), area under the wash-out curve (AWO), time to peak intensity (TTP) and the mean transit time (MTT) were statistically significant between ROImax and ROIrefer (all P=0.000). The △PI (△PI = PImax - PIrefer), △SL (△SL = SLmax - SLrefer), △AUC (△AUC = AUCmax - AUCrefer), △AWI (△AWI = AWImax - AWIrefer) and △AWO (△AWO = AWOmax - AWOrefer) of RCC were significantly higher than in AML (P=0.007, 0.000, 0.003, 0.048, 0.009, respectively), while the TTP (△TTP = TTPmax - TTPrefer) and △MTT (△MTT = MTTmax - MTTrefer) of RCC were significantly lower (both P=0.000). In comparison with papillary renal cell carcinoma (pRCC) and chromophobe renal cell carcinoma (chRCC), the △PI, △SL, △AUC and △AWO of ccRCC were all larger (all P<0.05). The sensitivity, specificity, and AUC of the combination of parameter difference for differentiating RCC from AML were 100%, 81.2%, and 0.965, respectively, and for differentiating ccRCC from pRCC and chRCC, 85.71%, 85.92% and 0.911, respectively. CEUS quantitative parameters have value in differentiating small RCC from AML and distinguishing ccRCC from pRCC and chRCC.

Differentiation of Angiomyolipoma With Minimal Fat from Clear Cell Renal Cell Carcinoma Using Non-contrast Multiparametric Magnetic Resonance Imaging.

This study was conducted to ascertain the optimal combination of non-contrast magnetic resonance (MR) imaging sequences for the differential diagnosis between small angiomyolipoma (AML) with minimal fat and clear cell renal cell carcinoma (CCRCC). Thirty-nine patients with pathologically proven AML with minimal fat (n=6) or CCRCC (n=33) measuring 4 cm or less were included. All underwent MR imaging before partial nephrectomy or percutaneous biopsy. Four quantitative parameters of tumors were evaluated: signal intensity (SI) index of T1W- gradient-echo imaging, SI index of T2- fat suppression imaging (T2-SI index), apparent diffusion coefficient (ADC) value, and standard deviation (SD) of ADC. These quantitative parameters were compared using Wilcoxon rank-sum test and receiver operating characteristic (ROC) curve analyses. The optimal combination of quantitative parameters was sought using logistic regression analysis. Comparison of quantitative parameters showed that the T2-SI index (median, AML with minimal fat vs. CCRCC; 0.74 vs. 1.27, p<0.001), ADC value (1.12 vs. 1.75, p=0.005), and SD of ADC (104 vs. 233, p<0.001) were significantly lower in AML with minimal fat than CCRCC. From the ROC curve analysis, the highest area under the curve (1.000; 100% sensitivity; 100% specificity) was obtained using the logistic regression model with the SD of ADC and T2-SI index or ADC value as explanatory variables. SD of ADC combined with T2-SI index or ADC value exhibited the highest diagnostic performance for differentiating small AML with minimal fat from CCRCC.

Transarterial Embolization for Sporadic Renal Angiomyolipoma: Patient Selection and Technical Considerations for Optimal Therapeutic Outcomes.

Although renal angiomyolipoma (AML) is a benign tumor, treatment may be necessary occasionally because it can cause potentially life-threatening retroperitoneal hemorrhage. Transarterial embolization (TAE) is a safe and effective treatment option to prevent the hemorrhagic rupture of AMLs and relieve the symptoms caused by enlarged lesions or active bleeding. However, there is no clear consensus regarding the indications for prophylactic TAE in patients with sporadic renal AMLs. In urgent TAE for bleeding AMLs, there is a likelihood of incomplete embolization when the focus is on stabilizing the clinical symptoms. This pictorial essay discusses the patient selection and technical considerations to achieve optimal therapeutic effects as well as the follow-up findings after TAE.

Association of CT Scan Parameters with the Risk of Renal Angiomyolipoma Rupture; a Brief Report.

Introduction:Rupture of renal angiomyolipoma (AML) is an emergency and life-threatening complication. This study aimed to evaluate the association of computed tomography (CT) scan parameters with the risk of rupture in renal AMLs.Methods:In this retrospective cross-sectional study, patients who were referred to a referral university hospital with diagnosis of AML, between 2007 and 2019, were included. Patients were divided into ruptured and non-ruptured cases based on surgery and CT scan findings and the baseline characteristics as well as CT scan parameters were compared between the two groups.Results:20 AML patients with the mean age of 39.6 ± 12.5 years were included (75% female). The lesion was ruptured in 8 (40%) patients. The mean size of the lesion was ‎97.0 ± 15.9 mm‎‏ in the ruptured and ‏‎72.0 ± 29.4‎‏ in the non‎-‎ruptured AML ‏‎(‎p ‎= ‎‏0.045). The ‎mean fat density based on non-contrast enhanced CT (NCCT) scan (-‎56.1 ± 16.3 ‎vs ‎-‎‎74.9±24.1; ‏p = ‏‎0.018) and contrast enhanced CT (CECT) scan (-‎20.8 ± 16.9 ‎vs ‎-‎‎50.5 ± 31.7; ‏p ‏= ‏‎0.‎016) was significantly higher in the ruptured cases. Total tumor density based on NCCT scan was significantly greater in the ruptured ‎AMLs ‏(‏‎19.6 ± 25.9 ‎‏ vs‎ ‎-22.7±41.6, p=0.033). Conclusion:It seems that some CT scan parameters such as mean fat density and ‎total tumor density ‏could be used for differentiation between ruptured and non-ruptured AMLs.

Adult renal angiomyolipomas: A retrospective analysis of the histological subtypes and their clinicoradiological correlates.

Renal angiomyolipomas (AMLs) are rare, benign mesenchymal tumors of the kidney. Asian data on the prevalence of the subtypes of AMLs and their association with tuberous sclerosis are sparse prompting us to evaluate the clinicopathological characteristics of these tumors. We included cases diagnosed from 2001 to 2021 extracting demographic details, clinical presentation, syndromic association with tuberous sclerosis, and preoperative clinicoradiological features from the electronic medical records. Ninety-five cases of adult renal AML were diagnosed among 2402 renal tumors, a prevalence of 3.95%. Forty tumors (42%) were detected incidentally; two patients had life-threatening retroperitoneal hemorrhage. Tuberous sclerosis complex (TSC) was associated with ten cases (10.5%). These patients were a decade younger than those in the non-TSC group (P = 0.008) and had bilateral, multiple, and larger tumors (P = 0.0009, 0.001, and 0.047, respectively). Microscopically, classic and epithelioid subtypes were seen in 87 (91.6%) and 8 cases (8.4%), respectively. Hemorrhage was more common in the epithelioid subtype (P = 0.13). HMB-45, melan-A, and smooth muscle actin immunohistochemistry were useful in cases which lacked the prototypical classic histology and for confirming a diagnosis of epithelioid AML. The prevalence of renal AML in our series was four times higher, and the mean age at diagnosis was a decade earlier than that reported in Western literature but similar to data from two Asian countries. Similar studies from other countries will help ascertain if these differences in prevalence can be attributed to ethnic differences.

Analysis of renal lesions in Chinese tuberous sclerosis complex patients with different types of TSC gene mutations.

We sought to explore the relationship between renal lesion features and genetic mutations in tuberous sclerosis complex (TSC) patients. TSC patients with renal lesions were subjected to TSC1/2 gene next-generation sequencing (NGS). TSC1/2 mutation types and imaging examinations were screened for combined analysis of genetic and clinical features. Seventy-three probands among TSC patients with renal lesions were included. Twenty affected relatives were also included. In total, 93 patients were included. Eighty patients (86.0%) had bilateral renal angiomyolipomas (AMLs), and one had epithelioid AML. Two patients had polycystic kidney disease, one had renal cell carcinoma, and one had Wilms tumor. Among the 73 probands, four had TSC1 mutations, 53 had TSC2 mutations, and 16 had no mutations identified (NMI). There was no statistically significant difference between TSC1 mutation, TSC2 mutation and NMI group (P= 0.309), or between familial and sporadic groups (P= 0.775) when considering AML size. There was no statistically significant difference between pathogenic/likely pathogenic and benign/likely benign/NMI groups (P= 0.363) or among patients with different mutation types of TSC2 (P= 0.906). The relationship between the conditions of TSC gene mutations and the severity of renal lesions still needs more analysis. Patients with NMI, particularly those with familial disease, need more attention because the pathogenesis remains unknown.

Giant Renal Angiomyolipoma: A Case Report

Renal Angiomyolipoma (AML), moreover known as a renal hamartoma, is a solid tumor with no malignant characteristics. The inheritance pattern of renal AML is autosomal dominant. If the lesion grows to a large size, a series of clinical manifestations and important complications might also occur. This research paper presents a case of huge renal AML in a 47-year-old lady, who visited the Emergency Department of Bahrain Defence Forces Hospital with right-sided abdominal pain of sudden onset. The patient underwent a total right nephrectomy. The resected mass was sized 10.5 x 13 x 14 cm. Postoperative histopathological examination confirmed the lesion as a huge renal AML. Due to the huge size of the tumor, it is crucial to record similar cases, along with their diagnosis and treatment. Keywords: Abdominal pain, Angiomyolipoma, Hamartoma, Kidney Neoplasms, Nephrectomy