Abstract: Active treatment of renal angiomyolipomas was historically recommended when tumors measured greater than 4 cm or grew rapidly because of the risk of hemorrhage. However, contemporary data suggests that some larger renal angiomyolipomas can also be managed safely with active surveillance.
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.
contemporary experience in the management of angiomyolipoma
Guidelines for management of angiomyolipoma are based on case series [12],[13] and suggest that angiomyolipoma in patients with TSC grow more rapidly and are more prone to complications than angiomyolipoma in non-TSC patients [7]. However data on the natural history of angiomyolipoma in sporadic LAM are very sparse and it is not clear if angiomyolipoma in these patients really are less prone to haemorrhage and should be treated differently from those with TSC. We have examined the clinical characteristics, growth rate and complications of angiomyolipoma in women with sporadic-LAM to optimise screening protocols for these patients.
Renal angiomyolipomas (AMLs) are considered the most prevalent benign renal tumor. Renal AMLs are generally composed of blood vessels, smooth muscles, and adipose tissues. Although most of these tumors are found incidentally on radiological imaging, symptomatic presentations such as flank pain, gross hematuria, or severe retroperitoneal hemorrhage may also exist. Imaging plays a central role in the diagnosis and management of these tumors. This activity reviews the evaluation, treatment, complications, and prognosis of renal angiomyolipomas and highlights the role of the interprofessional team in evaluating and treating patients with this condition.
Imaging plays a central role in the diagnosis and management of renal angiomyolipomas.[4] The tumors contain variable amounts of the same three tissue elements (vascular, muscular, and adipose). Variations will have different pathological, radiological, and clinical features.[5]
The management of angiomyolipomas is generally based on the clinical manifestations, tumor size, number, growth pattern, and malignant potential.[2][5] For example, epithelioid angiomyolipoma of the kidney is considered an uncommon subtype of angiomyolipoma, which is potentially malignant.[10]
Specific selection depends on patient characteristics, tumor size, and specific location, as well as local experience and expertise. Thermal ablative therapy has the advantage of being able to perform simultaneous percutaneous renal biopsies and being effective regardless of the underlying nature of the tumor. This gives them a significant advantage over selective angiographic embolization, where the diagnosis has to be clear and definitive before treatment, although embolization remains the preferred minimally invasive procedure for angiomyolipomas. The most commonly used thermal ablative modalities include cryotherapy and radiofrequency ablation.
Any woman of childbearing age diagnosed with renal angiomyolipoma who plans to become pregnant should seek consultation to discuss the management of her condition before and during the pregnancy. Pregnancy is considered a significant risk factor for disease progression and complications as the tumor mass will likely grow and may rupture while she is carrying.[5][11]
Another intriguing observation in our series is the fact that nine of the 36 cases studied (25%) were oncocytomas or chromophobe renal-cell carcinomas. This significantly increased incidence was seen both in sporadic and tuberous sclerosis cases. Recently, in one of the coauthors' experience (MBA) with a series of 405 consecutive cases of renal-cell neoplasms from a single institution (61), the combined proportion of renal oncocytoma and chromophobe renal-cell carcinoma was 12.6%, compared with 25% in the present study (P =.04). The rationale to group these two kinds of tumors is the emerging evidence that both entities may be in fact related from the histogenetic standpoint. Both chromophobe renal-cell carcinomas and renal oncocytomas are derived from the intercalated cells of the collecting ducts (62, 63); share some cytogenetic abnormalities (64); have overlapping morphologic (65, 66), immunohistochemical (67), and ultrastructural (68) features; and occur in cases of renal oncocytosis (69). Similarly, in the previously reported cases in the literature of coexisting angiomyolipomas and renal-cell neoplasia, an unusually high incidence of oncocytomas associated with angiomyolipoma is also seen (12%). Whether this overrepresentation of this group of neoplasms in our series and/or in the collective literature is secondary to selection/reporting bias or, conversely, has true pathogenetic implications is unknown at this point.
Renal angiomyolipoma is an uncommon renal neoplasm that exhibits a benign course (1). Although more cases are incidentally identified because of the growing use of medical imaging, cases presenting with large-sized angiomyolipomas (greater than 4 cm), spontaneous hemorrhage or flank pain, which require invasive treatment, are still relatively rare (1). Surgical removal and embolization are the standard treatments for symptomatic angiomyolipoma; however, renal artery embolization has gained wider acceptance for its mini-invasiveness (1). There is no consensus on the embolization material. Polyvinyl alcohol (PVA) particles, absolute ethanol, coils, microcoils, and gelatin sponge have been successfully applied in the literature (2-7). Absolute ethanol has been widely accepted as a reliable embolization material for renal angiomyolipoma (4,5,8,9). However, medical-grade absolute ethanol is not currently commercially available in China. Lipiodol is a conventional embolization agent used in the interventional treatment of hepatocellular carcinoma (10). Reports on lipiodol as an embolization material for renal angiomyolipoma are limited (8). Here, we present our experience of using a mixture of lipiodol and PVA particles as embolization materials to treat symptomatic renal angiomyolipoma.
Renal angiomyolipoma is a common benign tumor composed of three tissue components: blood vessels, smooth muscle and adipose cells (2,6,8). It is classically identified by the presence of fat on CT, MRI, or ultrasonography (2,7,12). Angiomyolipomas greater than 4 cm are prone to spontaneous hemorrhagic rupture due to the abnormal, thick-walled vessels (3,4,13). Renal embolization has proved to be an effective treatment for renal angiomyolipoma for different purposes, namely for the acute management of tumor bleeding, prophylaxis of high-risk tumor, and pre-operative adjuncts for surgery (3).
Active surveillance of angiomyolipoma is a reasonable approach to the initial treatment of the disease, because of the slow growth rate and uncomplicated course of management (1). When invasive treatments are needed, renal conservation is vital regardless of the difference in treatment options (2,5). Embolization has a major advantage over surgery, because functional renal tissue is spared as much as possible (2). Embolization is obviously mini-invasive compared to surgery. Renal function can be reliably protected through super-selective catheterization, as proven by the results of our study.
Preventing acute complication of renal angiomyolipoma (AML), preserving renal parenchyma, and improving long-term renal function are the treatment targets of renal angiomyolipoma. Treatment should be considered for symptomatic lesions or those who are at risk of complications, especially bleeding symptoms, which are linked to tumor size, angiogenic component grade, and presence of tuberous sclerosis complex (TSC). Selective arterial embolization (SAE) has become the new norm for preventive or emergency treatment of renal AMLs with minimally invasive selective targeting of small arterial feeders, we aimed to assess the efficacy and safety of selective renal arterial embolization (SAE) in the management of complicated renal angiomyolipoma and to detect the predictors of prophylactic SAE in cases of non-complicated AML.
Renal transplantation has profound improvements in mortality, morbidity, and overall quality of life compared to renal replacement therapy. This report aims to illustrate the use of ex-vivo partial nephrectomy in a patient with a renal angiomyolipoma prior to living donor transplantation. The surgical outcomes of the donor nephrectomy and recipient transplantation are reported with 2 years of follow-up. Both the donor and recipient are healthy and without any significant comorbidities. In conclusion, urologic techniques such as partial nephrectomy can be used to expand the living donor pool in carefully selected and well informed transplant recipients. Our experience demonstrated a safe and positive outcome for both the recipient and donor, and is consistent with other reported outcomes in the literature.
Radical nephrectomy is the standard treatment for localized renal cellcarcinoma (RCC) in patients with a normal contra lateral kidney. However, inpatients with a solitary functioning kidney, nephron sparing surgery (NSS) ismandatory [1]. NSS is also desirable in benign renal tumours such asangiomyolipoma [2]. It therefore should also be considered when there isuncertainty about the diagnosis because of the possibility of a benign renaltumour, angiomyolipoma or a complex cyst. In recent years, NSS has also beenproposed for RCC with a normal contra-lateral kidney with excellent five yearcancer-specific survival results being reported [3, 4, 5]. Such a surgicaloption is particularly suited for small RCCs, which seem to be best suitedfor renal sparing surgery [6]. In fact, with the advent and development ofultrasound and computerized tomography (CT), small RCCs are being detectedwith increasing frequency [7, 8]. With this increase of number, there hasbeen a decrease in the average size of tumours found [7, 8]. The relationshipbetween the clinical and pathologic size of renal tumours has been studiedbefore with variable results [9, 10, 11, 12, 13, 14]. Some of studiessuggested preoperative CT imaging may overestimate the pathologic size, whichmay have implications for planning NSS [9, 10, 11, 12, 13]. Our aim was todetermine what extent do CT measurements over or under-estimate the size ofsmall renal tumours and how it can impact of their management. 2ff7e9595c
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