Angiomyolipoma of the kidney: from simple hamartoma to complex tumour

Imaging appearances of perinephric myxoid pseudotumor of fat (PMPF)

AIM

This study aimed to identify the imaging feature of perinephric myxoid pseudotumor of fat (PMPF) in a large cohort.

MATERIALS AND METHODS

Institutional radiology and pathology databases were queried for PMPF for the period from January 2010 to December 2023. Of the 22 identified individuals, two were excluded due to nonavailability of computed tomography (CT) or magnetic resonance (MR) images and five due to lack of pathological confirmation. The study cohort comprised of 15 individuals (males = 10), with median age of 59 years (range: 26-87 years). Three abdominal radiologists in consensus reviewed all relevant CT, magnetic resonance imaging (MRI) and positron emission tomography (PET) images.

RESULTS

Seventeen tumuors were analysed since two individuals had bilateral tumuors. The tumuors were at the renal hilum (n=7) or perinephric space (n=10). Two imaging patterns were seen: hazy ill-defined predominantly fatty mass (n=9) or a soft tissue mass (n=8) with variable fat content (0-90%). At presentation, the tumuors ranged in size from 1.5 to 16.5 cm (median: 6.2 cm). The perihilar tumuors encased central renal vessels without occlusion or thrombus. Ureteric encasement and mild hydronephrosis were seen in 11 and 4 tumuors, respectively. Most (9 of 13) of the affected native kidneys and all transplant kidneys (n=5) showed parenchymal poor contrast enhancement. Tumuors with greater than 12-month follow-up (n=11) showed a median growth of 15%.

CONCLUSION

PMPF may be considered in the diagnosis of tumuors with soft tissue and fat components situated at the renal hilum or perinephric space. The delayed contrast enhancement, relative lack of mass effect for size, and poor function of affected kidney are diagnostic features.

Spontaneous rupture and hemorrhage of renal epithelioid angiomyolipoma misdiagnosed to renal carcinoma: a case report

BACKGROUND

Renal epithelioid angiomyolipoma is a rare and unique subtype of classic angiomyolipoma, characterized by the presence of epithelioid cells. It often presents with nonspecific symptoms and can be easily misdiagnosed due to its similarity to renal cell carcinoma and classic angiomyolipoma in clinical and radiological features. This case report is significant for its demonstration of the challenges in diagnosing epithelioid angiomyolipoma and its emphasis on the importance of accurate differentiation from renal cell carcinoma and classic angiomyolipoma.

CASE PRESENTATION

A 58-year-old Asian female presented with sudden left flank pain and was initially diagnosed with a malignant renal tumor based on imaging studies. She underwent laparoscopic radical nephrectomy, and postoperative histopathology confirmed the diagnosis of epithelioid angiomyolipoma. The patient recovered well and is currently in good health with regular follow-ups. This case highlights the diagnostic challenges, with a focus on the clinical, radiological, and histopathological features that eventually led to the identification of epithelioid angiomyolipoma.

CONCLUSIONS

Epithelioid angiomyolipoma is easily misdiagnosed in clinical work. When dealing with these patients, it is necessary to make a comprehensive diagnosis based on clinical symptoms, imaging manifestations, and pathological characteristics.

Hepatic perivascular epithelioid cell tumors: Benign, malignant, and uncertain malignant potential

In 2013, the World Health Organization defined perivascular epithelioid cell tumor (PEComa) as "a mesenchymal tumor which shows a local association with vessel walls and usually expresses melanocyte and smooth muscle markers." This generic definition seems to better fit the PEComa family, which includes angiomyolipoma, clear cell sugar tumor of the lung, lymphangioleiomyomatosis, and a group of histologically and immunophenotypically similar tumors that include primary extrapulmonary sugar tumor and clear cell myomelanocytic tumor. Clear cell tumors with this immunophenotypic pattern have also had their malignant variants described. When localizing to the liver, preoperative radiological diagnosis has proven to be very difficult, and most patients have been diagnosed with hepatocellular carcinoma, focal nodular hyperplasia, hemangioma, or hepatic adenoma based on imaging findings. Examples of a malignant variant of the liver have been described. Finally, reports of malignant variants of these lesions have increased in recent years. Therefore, we support the use of the Folpe criteria, which in 2005 established the criteria for categorizing a PEComa as benign, malignant, or of uncertain malignant potential. Although they are not considered ideal, they currently seem to be the best approach and could be used for the categorization of liver tumors.

A retrospective clinical analysis of 11 cases of PEComa from different sites

PURPOSE

The objective of this paper is to offer a thorough examination of the clinical presentations, etiology, and treatment strategies associated with perivascular epithelioid cell tumors (PEComas).

METHODS

This retrospective study examined the comprehensive archival data of PEComa cases diagnosed at Beijing Hospital from 2015 to 2023. The pathology slides of all patients were thoroughly reassessed by two experienced pathologists. A thorough retrospective analysis was undertaken, incorporating clinicopathological data including gender, age at diagnosis, initial clinical manifestations, signs, disease onset site, tumor markers, imaging findings, therapeutic modalities, pathological features, immunohistochemical profiles, treatment responses, and prognostic indicators. Patients were evaluated for disease severity according to established pathological classification criteria and were followed up until the designated analysis cut-off date. In instances where patients were unable to be monitored on-site, they were contacted via telephone for postoperative follow-up inquiries.

RESULTS

This study included 11 patients with ages ranging from 17 to 66 years old, presenting with the disease in multiple anatomical sites, including the retroperitoneum (2/11), liver (4/11), kidney (4/11), lung (1/11), and broad ligament of the uterus (1/11). Most patients presented with non-specific clinical symptoms and were subsequently diagnosed with space-occupying lesions upon physical examination. The tumor demonstrated progressive growth and enlargement, which could result in compression of neighboring organs. Preoperative imaging alone is insufficient for a definitive diagnosis of PEComa, but MRI can provide an initial evaluation of the tumor's potential malignancy. Molecular marker testing specific to PEComa, such as HMB-45 (90.0%), SMA (81.8%), Melan-A (90.9%), vimentin (90.9%), and Desmin (36.3%), was conducted on all patients. No adjuvant therapies were administered postoperatively. Upon analysis, no instances of relapse at the primary site or the development of new tumors at other sites were observed. Regular imaging reviews of three patients with malignant PEComa post-surgery showed no evidence of recurrence.

CONCLUSIONS

The clinical presentation, tumor biomarkers, and imaging characteristics of PEComa lack specificity, necessitating dependence on pathology and immunohistochemistry for precise diagnosis. The mainstay of treatment consists of surgical resection, with patients typically experiencing a favorable prognosis.

Arterial embolization in the treatment of multiple renal and hepatic hamartomas with spontaneous hemorrhage and 2-year follow-up: a case report

BACKGROUND

Hamartoma is a common benign tumor that usually occurs in the kidney, liver, lung, and pancreas. Large renal hamartomas may spontaneously rupture and hemorrhage, which is potentially life-threatening.

CASE PRESENTATION

This report describes a 46-year-old Han Chinese female patient with multiple renal and hepatic hamartomas with rupture and hemorrhage of giant hamartoma in the left kidney. She underwent arterial embolization three times successively, and her condition was stable during the 2-year follow-up. This report includes a review of the relevant literature CONCLUSIONS: the findings in this report and previous literature suggest that arterial embolization can not only rapidly treat hamartoma hemorrhage in the acute phase but can also effectively control multiple lesions in the long term after repeated multisite arterial embolization.

mTOR eosinophilic renal cell carcinoma: a distinctive tumor characterized by mTOR mutation, loss of chromosome 1, cathepsin-K expression, and response to target therapy

In the spectrum of oncocytic renal neoplasms, a subset of tumors with high-grade-appearing histologic features harboring pathogenic mutations in mammalian target of rapamycin (mTOR) and hitherto clinical indolent behavior has been described. Three cases (2F,1 M) with histologically documented metastases (lymph node, skull, and liver) were retrieved and extensively investigated by immunohistochemistry, FISH, and next-generation sequencing. Tumors were composed of eosinophilic cells with prominent nucleoli (G3 by ISUP/WHO) arranged in solid to nested architecture. Additionally, there were larger cells with perinuclear cytoplasmic shrinkage and sparse basophilic Nissl-like granules, superficially resembling the so-called spider cells of cardiac rhabdomyomas. The renal tumors, including the skull and liver metastases, showed immunoexpression PAX8, CK8-18, and cathepsin-K, and negativity for vimentin. NGS identified mTOR genetic alterations in the three cases, including the skull and liver metastases. One patient was then treated with Everolimus (mTOR inhibitors) with clinical response (metastatic tumor shrinkage). We present a distinct renal tumor characterized by high-grade eosinophilic cells, cathepsin-K immunohistochemical expression, and harboring mTOR gene mutations demonstrating a malignant potential and showing responsiveness to mTOR inhibitors.

Engineered organoids for biomedical applications

As miniaturized and simplified stem cell-derived 3D organ-like structures, organoids are rapidly emerging as powerful tools for biomedical applications. With their potential for personalized therapeutic interventions and high-throughput drug screening, organoids have gained significant attention recently. In this review, we discuss the latest developments in engineering organoids and using materials engineering, biochemical modifications, and advanced manufacturing technologies to improve organoid culture and replicate vital anatomical structures and functions of human tissues. We then explore the diverse biomedical applications of organoids, including drug development and disease modeling, and highlight the tools and analytical techniques used to investigate organoids and their microenvironments. We also examine the latest clinical trials and patents related to organoids that show promise for future clinical translation. Finally, we discuss the challenges and future perspectives of using organoids to advance biomedical research and potentially transform personalized medicine.

Posterior urethral hamartoma with hypospadias in a child: a case report and literature review

Background

Hamartoma is a mass formed by the proliferation and disorder of two or more kinds of cells inherent in normal organs or anatomical parts, which can occur in any part of the body. The most common hamartoma are kidney hamartoma, spleen hamartoma, liver hamartoma, and lung hamartoma. Urethral hamartoma is extremely rare in clinical practice.

Case report

Combined with literature review, the diagnosis and treatment process of a child with posterior urethral hamartoma and hypospadias in our hospital were analyzed. The patient was cured after surgical treatment, the lesion was completely removed, the appearance was satisfactory, and there was no recurrence, urethral stricture, urethral fistula, and other complications. The pathological results of this case support the histological diagnosis of hamartoma, which provides reference for the clinical diagnosis and treatment of congenital malformation and tumor of urogenital in children.

Conclusion

When a child has posterior urethral hamartoma, the symptoms may not be very typical, and it is often combined with urethral malformation. Therefore, it is necessary to perform careful physical examination combined with pathological examination to be able to make an accurate diagnosis. Under normal circumstances, the prognosis of urethral hamartoma is good. However, more cases are needed to be observed for verification, and a long-term effective follow-up after surgery is needed.

Current management of benign retroperitoneal tumors

Benign retroperitoneal tumors (BRT) represent a rare group of heterogeneous diseases. The literature lacks high-quality evidence about the optimal management of BRT, and most of the information available takes the form of case reports or case series. The aim of this review is to provide an overview of current management strategies for adult patients with BRT. A literature search using PubMed indexed articles was conducted and BRT were classified into five different biological subgroups: 1) lipomatous tumors, 2) smooth muscle tumors, 3) peripheral nerve sheath tumors, 4) myofibroblastic tumors, and 5) others. Tumors that are primarily pelvic in origin were excluded. Despite the significant heterogeneity of the disease, several generic considerations have emerged and can be applied to the management of BRT. Specifically, the risk of misdiagnosing a BRT with another pathology such as retroperitoneal sarcoma is notable. When encountered, suspected BRT should therefore be referred to a specialized sarcoma center. Multidisciplinary tumor boards, present at these centers, have a pivotal role in managing BRT. The decision of whether to offer surgery, nonsurgical treatment or a "watch-and-wait" approach should be made after multidisciplinary discussion, depending on tumor histology. Moving forward, collaborative research efforts dedicated to BRT remain crucial in gathering evidence and knowledge to further optimize patient care.

Comparison of Polyvinyl Alcohol Versus Combination of Lipiodol-Bleomycin Emulsion and NBCA-Lipiodol Emulsion for Renal Angiomyolipoma Embolization: A Prospective Randomized Study

BACKGROUND. Consensus is lacking regarding optimal embolic agents for transcatheter arterial embolization (TAE) of renal angiomyolipomas (AMLs). OBJECTIVE. The purpose of our study was to compare the safety and efficacy of TAE with polyvinyl alcohol (PVA) and TAE with a combination of ethiodized oil (Lipiodol)-bleomycin emulsion and N-butyl cyanoacrylate (NBCA)-Lipiodol emulsion for the treatment of patients with large or symptomatic AMLs. METHODS. This prospective study enrolled patients referred for TAE of a large (> 4 cm) or symptomatic renal AML from July 2007 to December 2018. Patients were randomized to undergo TAE using PVA particles or a combination of Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion. Patients underwent serial clinical follow-up visits and follow-up CT or MRI examinations after TAE. Outcomes were compared between groups. RESULTS. Seventy-eight patients were enrolled. After exclusions, the analysis included 72 patients (15 men, 57 women; mean age, 35.0 years; 51 patients with hematuria, 66 patients with flank pain): 35 patients were randomized to treatment by PVA and 37 were randomized to treatment by a combination of Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion. Complete occlusion of all angiographically visible arterial supply was achieved in all patients. No major adverse event occurred in any patient. The mean follow-up after TAE was 77 ± 45 (SD) months (range, 37-180 months). The frequency of resolution of hematuria after initial TAE without recurrence was greater after treatment by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than by PVA (100.0% vs 80.0%, respectively; p = .03). At 12-month follow-up, the frequency of complete resolution of flank pain was higher after treatment by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than by PVA (100.0% vs 75.0%, p = .03). Mean reduction in AML volume at 36 months or longer after TAE versus at baseline was greater in patients treated by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than in those treated by PVA (98.0% vs 85.7%, respectively; p = .04). The frequency of complete response by modified RECIST (mRECIST) criteria at 36 months or longer after TAE was greater in patients treated by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than by PVA (94.6% vs 74.3%, p = .04). The rate of repeat TAE was higher among patients treated by PVA than among those treated by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion (25.7% vs 8.1%, p = .04). CONCLUSION. Superior outcomes after TAE of AML were achieved using Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than using PVA. CLINICAL IMPACT. TAE using a combination of Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion is a safe and effective treatment option for large or symptomatic AMLs. TRIAL REGISTRATION. Chinese Clinical Trial Registry ChiCTR2100053296.

Cytomorphology of renal angiomyolipoma: performance and accuracy of touch preparation of core needle biopsy

INTRODUCTION

The recognition of renal angiomyolipoma (AML) can be challenging based on cytology preparations such as touch preparation (TP) of core needle biopsy (CNB) and fine needle aspiration. This study evaluated the cytologic features and performance of TP of CNB during rapid onsite evaluation (ROSE) of renal AML.

MATERIALS AND METHODS

A pathology database search was performed between 2000 and 2021 for renal CNB specimens with ROSE using TP that were primarily favored AML on preliminary impression and/or confirmed AML on CNB or subsequent resection.

RESULTS

Twenty confirmed AML were identified (90% female, median age 65.5 years). Sixteen (80%) were deemed adequate for diagnosis at the time of ROSE, and 9 of 16 (56%) had available onsite impression: AML was favored in 4 of 9 cases (44%). Examination of TP slides revealed spindle/epithelioid cells in 20 (100%), adipose tissue in 14 (70%), and blood vessels in 3 (15%). All AML cases were subsequently confirmed by immunohistochemistry. Additionally, 3 other cases with ROSE favoring AML revealed to be "renal parenchyma with fibrosis," clear cell papillary renal cell tumor and clear cell renal cell carcinoma.

CONCLUSIONS

Onsite evaluation of TP ensures adequate material for diagnosis in most renal AML. Spindle/epithelioid cells were the most common component seen on TP, followed by adipose tissue. Blood vessels were rarely seen. While the recognition of AML at ROSE can be challenging, proper evaluation is important in obtaining adequate diagnostic tissue. Correlation with CNB and utilization of immunohistochemistry are crucial for arriving at the diagnosis.

p53 aberration and TFE3 gene amplification may be predictors of adverse prognosis in epithelioid angiomyolipoma of the kidney

BACKGROUND

Although epithelioid angiomyolipoma of the kidney has been studied by several groups, the reported prevalence of malignant behavior remains uncertain and there are not yet definitive predictive biomarkers. We evaluated the behavior of renal epithelioid angiomyolipoma in a consecutive series in a single institution and investigated the prognostic value of aberrant p53 expression and TFE3 gene abnormality.

METHODS

We retrospectively reviewed 14 epithelioid angiomyolipomas, most with pure or close to pure epithelioid components, comprising 12 consecutive cases who had attended our institution and two consultation cases. Fluorescence in situ hybridization with TFE3 break-apart probe was performed on 14 cases. The 14 cases were also labeled for p53 and TFE3 by immunohistochemistry. All cases were followed up.

RESULTS

Three of the epithelioid angiomyolipomas were strongly positive for TFE3 and two had a mutant expression of p53. Although no TFE3 gene rearrangement was found, the two tumors with strong TFE3 expression showed TFE3 gene amplification. Follow-up details were available for seven of the 12 consecutive cases: two of them had developed metastases and died (29%), their mean overall survival was 41 months, and both had mutant p53 expression. The two consultation cases with TFE3 gene amplification developed recurrence/metastasis within 1 year after surgery.

CONCLUSIONS

Our series study from a single institution presented the prevalence of malignant behavior in pure epithelioid angiomyolipomas, although the small number of cases with follow-up data greatly reduced the accuracy. p53 may be a prognostic marker for epithelioid angiomyolipoma. Cases with TFE3 gene amplification had poor prognoses.

Cutaneous Angiomyolipoma-A Distinct Entity That Should Be Separated From Classic Angiomyolipoma: Complete Review of Existing Cases and Defining Fundamental Features

Cutaneous angiomyolipoma is a rare mesenchymal tumor that is demographically, clinically, and immunohistochemically distinct from its renal and extrarenal counterparts. We present a case of cutaneous angiomyolipoma in the right retroauricular area of a 35-year-old male patient and provide a broad systematic review of the literature and the largest compilation of cutaneous angiomyolipomas reported to date. According to the findings presented in this review, we conclude that cutaneous angiomyolipoma should be completely separated from renal and extrarenal angiomyolipomas and therefore be considered a distinct entity in the classification of skin tumors.

Recurrent retroperitoneal extra-renal angiomyolipoma: A case report and review of literature

Introduction

Angiomyolipoma (AML) is the most prevalent renal mesenchymal neoplasm that almost always involves kidneys.

Case presentation

We present a rare condition of retroperitoneal extra-renal angiomyolipoma which relapsed after 4 years that caused acute abdominal pain.

Discussion

The liver is the most common site of extrarenal angiomyolipoma. Abdominal pain is the most common complaint of extra-renal angiomyolipoma. Computed tomography angiography is the best way for angiomyolipoma diagnosis and surgery and post-surgery chemotherapy is the way for its treatment.

Conclusion

extrarenal angiomyolipoma is an extremely rare condition that patients should be followed up for over 5 years by appropriate radiologic imaging.

1).

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Angiomyolipoma almost always involves kidneys.

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We present a retroperitoneal extra-renal angiomyolipoma case.

2)

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extra-renal angiomyolipoma is characterized as a benign tumor.

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We present a recurrent retroperitoneal extra-renal angiomyolipoma.

3)

surgery is one of the best ways to both diagnosis and treatment of retroperitoneal extra-renal angiomyolipoma.

Spontaneous rupture of renal angiomyolipoma and its management: A case report

a) Introduction and Importance

Angiomyolipomas of kidney are benign lesions that are generally an incidental finding on imaging. Rupture of angiomyolipoma is rare and fatal complication that requires early intervention.

b) Case Presentation

A 38 year old male patient presented with symptoms of right flank pain for 2 days. On clinical examination patient looked anxious, pale with right flank tenderness, guarding and signs of shock.

c) Clinical findings and investigations

CT scan showed renal angiomyolipoma with aneurysm formation and bleed from the lesion. Blood profile revealed low hemoglobin.

d) Interventions and Outcome

Right nephrectomy performed along 6 cycles of cardiopulmonary reususcitaion done with stable post operatively vitals.

e) Conclusion

Early diagnosis of complication of angiomyolipoma requires thorough clinical examination and judicious use of imaging. Immediate embolization or surgery must be performed for better outcome and survival rate.

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Angiomyolipoma is composed of fat, smooth muscle and blood vessels and presents among 0.3% of the population.

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Renal angiomyolipoma are prone to aneurysm formation and bleed, however a nontraumatic spontaneous renal hemorrhage from a sporadic renal angiomyolipoma is a rare condition.

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Mostly angiomyolipoma are asymptomatic and are diagnosed incidentally. CT scan is the diagnostic modality of choice.

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Patients with life-threatening hemorrhage require immediate intervention that includes embolization or surgery for better outcome and survival rate.

Epithelioid angiomyolipoma: a pathological entity discovered in Verona with the endorsement of Doctor Rosai

In this manuscript, we summarize the main features of angiomyolipoma highlighting the recognition of epithelioid angiomyolipoma and the discovery of immunohistochemical expression of HMB45 in a group of tumors that now are referred to as as PEComas. In this scenario, Dr. Rosai believed in our intuition, demonstrating his intellectual honesty and motivated us with his experience (“when a tumor seems malignant it is malignant”) and enthusiasm for the new entities (“in Verona, you use HMB45 instead of H&E”). He really pushed the improvement of the knowledge in this field.

Clear cell renal cell carcinoma with prominent microvascular hyperplasia: Morphologic, immunohistochemical and molecular-genetic analysis of 7 sporadic cases

Clear cell renal cell carcinoma (CCRCC) is well known for intratumor heterogeneity. An accurate mapping of the tumor is crucial for assessing prognosis, and perhaps this can be linked to potential success/failure of targeted therapies. We assembled a cohort of 7 CCRCCs with prominent vasculature and microvascular hyperplasia (ccRCCPV), resembling those seen in high grade gliomas. A control group of classic CCRCC with no variant morphologies was also included. Both groups were analyzed for clinicopathologic, morphologic, immunohistochemical, and molecular genetic features. No statistically significant differences in mRNA expression of studied genes between the two groups were found. Using NGS panel Trusight Oncology 500 (TSO500), only one clinically significant gene mutation, VHL c.263G > A, p. (Trp88Ter), was found. TMB (Tumor Mutation Burden) and MSI (MicroSatellite Instability) were low, and no copy number variations (CNVs) were detected in the study cohort. Prominent microvascular hyperplasia in CCRCC is a rare phenomenon. From molecular genetic point of view, these tumors do not appear to be different from classic CCRCC. Prognostically, they also demonstrated similar clinical behaviors.

A tissue-bioengineering strategy for modeling rare human kidney diseases in vivo

The lack of animal models for some human diseases precludes our understanding of disease mechanisms and our ability to test prospective therapies in vivo. Generation of kidney organoids from Tuberous Sclerosis Complex (TSC) patient-derived-hiPSCs allows us to recapitulate a rare kidney tumor called angiomyolipoma (AML). Organoids derived from TSC2-/- hiPSCs but not from isogenic TSC2+/- or TSC2+/+ hiPSCs share a common transcriptional signature and a myomelanocytic cell phenotype with kidney AMLs, and develop epithelial cysts, replicating two major TSC-associated kidney lesions driven by genetic mechanisms that cannot be consistently recapitulated with transgenic mice. Transplantation of multiple TSC2-/- renal organoids into the kidneys of immunodeficient rats allows us to model AML in vivo for the study of tumor mechanisms, and to test the efficacy of rapamycin-loaded nanoparticles as an approach to rapidly ablate AMLs. Collectively, our experimental approaches represent an innovative and scalable tissue-bioengineering strategy for modeling rare kidney disease in vivo.

Natural History and Treatment Strategies of Advanced PEComas: A Systematic Review

Simple Summary

In this article, we review the clinical features of advanced PEComas and show the diversity of reported data among authors, emphasizing the heterogeneity of molecular characterization and treatment strategy. Based on clinical data collected from 124 case reports, metastatic disease at diagnosis and a grouped version of the Bleeker’s risk category were the only factors significantly associated with death. Due to a significant number of missing data or short follow-ups, results regarding prognostic factors should, however, be interpreted with caution.

Abstract

PEComas is a family of rare mesenchymal tumors. This systematic review aims to better understand the natural history of advanced PEComas. After a search on the PubMed database and main oncology meeting libraries according to the PRISMA guidelines, 88 articles reported in the English literature were included. Data on clinical and histological features, treatments and outcomes were collected. To identify risk factors, univariate and multivariate analyses were performed. Seven cohorts of patients and 124 individual patients were identified. Focusing on case reports, most patients were metastatic, and the median overall survival (OS) of the entire cohort was 60 months (95%CI 33; NA). Risk factors significantly associated with OS in the multivariate analysis were the presence of metastasis at diagnosis (HR: 2.59, 95%CI 1.06; 6.33, p = 0.036) and the grouped-Bleeker’s risk category (HR: 4.66; 95%CI 1.07; 20.19; p = 0.039). In the metastatic population, only the presence of lymph node metastasis was associated with OS (HR: 3.11; 95%CI 1.13; 8.60, p < 0.05). Due to a lack of events, it was not possible to conclude on other factors. This review of the literature highlights the heterogeneity of literature data and shows the great diversity of clinical management strategies.

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.

Is There a Higher Incidence of Sporadic Renal Angiomyolipoma in Childhood Cancer Survivors?

Background

Cancer treatment can cause various long-term side effects, including those that impact ultrasound findings. During follow-up of childhood cancer survivors (CCSs), we often detected sporadic renal angiomyolipomas without histological confirmation (SAMLs), which is why we initiated this study. We compared the occurrence of SAML in CCSs to the previously reported data from a non-cancer population and correlated SAML with cancer treatment-related factors.

Methods

The cohort included 1098 CCSs (median age at cancer diagnosis (dg) 4.3 years) who had ultrasound follow-up (2014-2019). Of the CCSs, 525 (48%) were female, 132 (12%) had subsequent neoplasms (SNs), and 110 (10%) had genetic syndromes. CCSs were treated for lymphomas 269 (24%) and solid tumors 829 (76%). None of the CCSs had tuberous sclerosis complex (TSC).

Results

SAML developed in 48 (4.4%) CCSs; of these, 20 (42%) had SNs. The coincidence of SAMLs and SNs was found in CCSs with a follow-up period exceeding 20 years. The median age at SAML dg was 27.9 years (interquartile range (IQR) 22.3-34.1), and the median time to SAML dg was 22.6 years (IQR 17.4-27.6). Twenty-one (44%) CCSs developed multiple or bilateral SAMLs lesions; of these, six (12%) were in the radiotherapy field. SAML occurrence correlated with radiotherapy of the retroperitoneum (1.65-fold higher with 95% CI 0.90-3.02). The correlations with other cancer treatment factors and with female sex were less clear.

Conclusion

This study revealed the occurrence of SAMLs in CCSs to be 10 times higher than that in non-cancer studies. The current characteristics of CCSs with SAMLs: younger age, and more bilateral or multiple lesions are more similar to TSC associated angiomyolipoma. Moreover, we observed a coincidence of SAMLs with SNs. Our results support the hypothesis that SAML development in CCSs is not simply a late effect of therapy, and indicates other factors are involved in SAML development.

Cathepsin K: A Novel Diagnostic and Predictive Biomarker for Renal Tumors

Simple Summary

Our understanding of renal tumors has increased in the last years with the description of several novel entities. The expanding morphological spectrum complicates the pathologist’s diagnosis, often requiring immunohistochemical analysis. The role of cathepsin K immunoexpression is widened as a diagnostic tool in several renal tumors. This review describes the usefulness of cathepsin K in the differential diagnosis of renal neoplasms, highlighting the biological knowledge underpinning its expression. Moreover, cathepsin K seems to be a downstream marker of different genetic alterations, with a possible role as a predictive marker that may prospectively guide the development of therapeutic approaches as a molecular target.

Abstract

Cathepsin K is a papain-like cysteine protease with high matrix-degrading activity. Among several cathepsins, cathepsin K is the most potent mammalian collagenase, mainly expressed by osteoclasts. This review summarizes most of the recent findings of cathepsin K expression, highlighting its role in renal tumors for diagnostic purposes and as a potential molecular target. Indeed, cathepsin K is a recognized diagnostic tool for the identification of TFE3/TFEB-rearranged renal cell carcinoma, TFEB-amplified renal cell carcinoma, and pure epithelioid PEComa/epithelioid angiomyolipoma. More recently, its expression has been observed in a subgroup of eosinophilic renal neoplasms molecularly characterized by TSC/mTOR gene mutations. Interestingly, both TSC mutations or TFE3 rearrangement have been reported in pure epithelioid PEComa/epithelioid angiomyolipoma. Therefore, cathepsin K seems to be a downstream marker of TFE3/TFEB rearrangement, TFEB amplification, and mTOR pathway activation. Given the established role of mTOR inhibitors as a pharmacological option in renal cancers, cathepsin K could be of use as a predictive marker of therapy response and as a potential target. In the future, uropathologists may implement the use of cathepsin K to establish a diagnosis among renal tumors with clear cells, papillary architecture, and oncocytic features.