Large Angiomyolipoma Research Articles

Clinical Correlates of Renal Angiomyolipoma Subtypes in 209 Patients: Classic, Fat Poor, Tuberous Sclerosis Associated and Epithelioid

Angiomyolipomas classically present radiographically as fat containing lesions but some fail to demonstrate fat content. Histologically confirmed angiomyolipomas uniformly follow a benign course but rare epithelioid variants of angiomyolipoma can recur and metastasize. We investigated the clinical, radiographic and histological characteristics of each angiomyolipoma subtype. Pertinent data were recorded for 209 patients surgically treated for angiomyolipoma in 219 kidneys from 1981 to 2007. Classic and fat poor angiomyolipomas were classified radiographically based on the presence or absence of fat and classified histologically based on the presence of triphasic, monophasic or epithelioid histology. Median radiographic size was 3.2, 4.9 and 10 cm in patients with a single angiomyolipoma (59% of patients), multiple angiomyolipomas and tuberous sclerosis (probable or definite), respectively. In these 3 groups 65%, 47% and 33% of lesions were not suspected radiographically (fat poor angiomyolipoma). Fat poor angiomyolipomas were more commonly single, smaller and in older patients. Triphasic histology was evident in 76% of angiomyolipomas with 16% demonstrating a predominance of 1 component and 8% containing epithelioid features. Despite potentially aggressive findings in 18% (eg presence within the perinephric fat, lymph node involvement) no angiomyolipoma recurred during a mean followup of 3.4 years (range 0 to 24). A total of 28 (13%) patients with angiomyolipoma had concomitant renal cell carcinoma. A surprisingly high number of resected angiomyolipomas was not suspected radiographically indicating the importance of precise radiographic characterization to minimize nephrectomy for fat poor angiomyolipoma, which should remain a research priority. In this sizeable single institution series no triphasic, monophasic or epithelioid angiomyolipoma recurred despite potentially aggressive findings in a substantial proportion of cases.

Renal Angiomyolipoma: Long-term Results Following Selective Arterial Embolization

BackgroundThe treatment for and long-term outcome of renal angiomyolipoma (AML) at high-risk for bleeding has not been determined. ObjectiveTo evaluate the complication rates and the long-term outcomes among patients treated by selective arterial embolization (SAE) for a large or symptomatic renal AML. Design, setting, and participantsForty-one patients with 48 kidneys containing AML were treated by SAE at a single tertiary academic center. InterventionAll patients were treated by SAE and followed in a single center. MeasurementsSAE was performed with a mixture of 96% ethanol and polyvinyl alcohol particles. The variables used for the analysis included age, gender, presence of tuberous sclerosis (TS), and maximal tumor size prior to SAE. The study end points were recurrence of symptoms or bleeding, the need for re-embolization or surgery, and disease-specific survival. The mean follow-up period for the entire group was 4.8 yr. Results and limitationsMean patient age was 51 yr (range: 24–82), and the mean initial tumor size was 10.3cm. Successful SAE was achieved in 40 patients (91%) with a minor complication rate of 11%. Avoidance of surgery was achieved in 96% of the kidneys. No retroperitoneal hemorrhage was noted during follow-up, and 98% of the kidneys were preserved during the follow-up period. No significant changes in creatinine levels were noted following SAE (P=0.27). The freedom from surgical treatment at 5 yr following SAE was 94% (95% CI, 89–99%). Disease-specific survival of the entire cohort was 100%. The study is a retrospective, and treatment was not given according to prospective protocol, and therefore sample bias may be present. ConclusionsSAE of renal AML has long-term efficacy in preventing hemorrhagic complications of renal AML, and preservation of the involved kidneys is amenable in both TS and sporadic cases.

Renal Angiomyolipoma Causing Pyonephrosis

A 35-year-old male presented with the complaints of pain in the left flank and fever.He was found to have a large septated pyonephrotic kidney due to uretral obstruction caused by a large angiomyolipoma at the middle and lower pole. The patient was operated and left nephrectomy was done. He recovered well after the operation with resolution of pain and fever. Patients with angiomyolipoma may suffer from complications like pyonephrosis; therefore, they should be monitored closely so that more conservative management in the form of transarterial embolisation and open partial nephrectomy could be employed rather than going for more radical treatments like total nephrectomy.

Abdomen agudo en mujer gestante secundario a rotura espontánea de angiomiolipoma renal

We report the case of a 28-year-old pregnant woman with acute abdomen secondary to retroperitoneal hemorrhage caused by spontaneous rupture of a large angiomyolipoma. Even though most angiomyolipomata are asymptomatic and are discovered incidentally on imaging studies, these neoplasms may cause symptoms when they grow. The most frequent presenting symptoms are abdominal pain, palpable mass, and hematuria (Lenke's triad).

Giant renal angiomyolipoma with fatal hemorrhage due to a large pseudoaneurysm

We report a case of giant renal angiomyolipoma (AML) with a large pseudoaneurysm causing fatal hemorrhage. A 60-year-old woman presented with right-sided abdominal pain. Sonographic examination revealed a large hyperechoic renal mass. CT examination of the abdomen revealed a 15-cm AML of the right kidney with a large hemorrhagic area within it. Subsequent color Doppler examination revealed a 2.9-cm pseudoaneurysm arising from the upper segmental branch of the right renal artery. The patient, who was about to undergo transcatheter embolization of the pseudoaneurysm, died from cardio-respiratory arrest. The autopsy findings confirmed a large right renal AML containing a thrombosed pseudoaneurysm and a large perinephric hematoma.

Conservative management of giant symptomatic angiomyolipomas in patients with the tuberous sclerosis complex

To present two patients with the tuberous sclerosis complex in whom giant angiomyolipomas (AMLs) were managed conservatively for >20 years, as large (>4 cm) symptomatic AMLs are generally treated with embolization or nephrectomy because of the risks of haemorrhage. The first patient initially presented with bilateral renal AMLs replacing >70% of his parenchymal volume, and a large left renal cyst. Since presentation he was hospitalized three times, but has had no transfusions or procedures to treat his AMLs. His renal function has remained stable during this 21-year interval. The second patient initially presented with bilateral renal AMLs that were not amenable to nephron-sparing surgery. After removing her nonfunctioning left kidney, the 24-cm AML in her right kidney was managed conservatively for >20 years, during which she had 44 transfusions and 11 hospitalizations before uncomplicated right nephrectomy and subsequent need for haemodialysis. Conservative management of AMLs can preserve renal function for >20 years in patients with tuberous sclerosis at high risk of end-stage renal disease.

Interventional management of acute bleeding giant renal angiomyolipoma: Report of three cases and review of the literature

To report our experiences of catheter embolization of three acute bleeding giant renal angiomyolipoma and to discuss the diagnostic and interventional management of this tumor entity in an emergency and elective setting in review of the literature. Materials and methods Three female patients (43 ± 5.9 years) with giant renal angiomyolipomas (AML), two associated with tuberous sclerosis, presented with spontaneous acute perirenal hemorrhage and large retroperitoneal hematomas. Due to their age and intact parenchyma with normal renal retention parameters, they were treated with superselective transarterial embolization (TAE), applying a combination of particulate and liquid embolic material: 0.5–2 ml (300–500 μm/700–900 μm) Embospheres™ (Biosphere, France) were injected to block the tumor periphery followed by 0.2–1 ml mixture of Lipiodol™ (Byk Gulden, Germany) and Ethibloc™ (Ethicon, Germany) to occlude the feeder of the ruptured angiomyolipoma. All embolizations were successful and patients were discharged after 3–5 days. Follow-up MRI on discharge showed no bleeding and distinct atrophy of the embolized areas without impairment of normal renal parenchymal perfusion. Renal function remained normal during clinical and MRI follow-up (mean 28.3 ± 30.4 months). Conclusions In most patients with acute bleeding giant angiomyolipomas, it would be impossible to preserve the kidney by surgical attempts alone, so they should be, if technically possible, initially treated by selective arterial embolization. Catheter embolization should be considered as an elective therapy option in patients with symptomatic and/or large (>4 cm) AMLs. All AMLs associated with tuberous sclerosis should be monitored by annually MRI for lifetime to assess tumor growth and to predict complications.

肺リンパ管筋腫症に合併した巨大な腎血管筋脂肪腫の一例

A 27-year-old female with pulmonary lymphangioleiomyomatosis was referred to us because of the right large renal angiomyolipoma (AML), 10 cm in diameter, which was found by abdominal CT during close investigation of her pulmonary disease. About 6 months earlier she had received operation for pneumothorax and the histological examination disclosed pulmonary lymphangioleiomyomatosis (LAM). Clinically she does not have tuberous sclerosis. Partial nephrectomy was performed. The renal tumor arose from the lower part of the kidney with somewhat exophytic growth. She is now followed at outpatient clinic without recurrence of renal AML. Pulmonary LAM often associates with renal AML. Although pulmonary LAM is a progressive disease and has a poor prognosis, because of the risk of the rupture of renal AML, large renal AMLs should be treated. Recently several cases have been reported for whom nephron-sparing surgery was performed. This case is 10th report of LAM, which is associated with AML in Japan.

Giant Renal Angiomyolipoma Associated With Pulmonary Lymphangioleiomyomatosis: A Case Report

Renal angiomyolipomas are benign tumours known to appear sporadically and in association with genetic syndromes, including lymphangioleiomyomatosis. Treatment of large angiomyolipomas is usually indicated because of an increased risk of spontaneous haemorrhage. We report in a patient with radiographic criteria of pulmonary lymphangioleiomyomatosis, a successful trans-arterial embolization of a giant angiomyolipoma with active anemization due to retroperitoneal bleeding and deferred surgical treatment due to persistent symptoms. KEY OF DEFINITIONS FOR ABBREVIATIONS AML: Angiomyolipoma. LAM: Lynphangioleiomyomatosis. TSC: Tuberous sclerosis complex.

Management of renal abscess formation after embolization due to renal angiomyolipomas in two cases

Current management strategies of renal angiomyolipomas (AMLs) include observation, embolization and partial or total nephrectomy. Selective arterial embolization is an effective and safe treatment of large angiomyolipomas with low complication rates. Percutaneous drainage was the recommended treatment for renal abscess formation following the embolization. Herein we describe two cases which we performed percutaneous drainage of the liquefaction of entire tumors after embolization. Open surgery was needed for one of the patients who showed recurrence after percutaneous drainage and alcohol irrigation of the cavity, whereas percutaneous drainage was the sufficient treatment for the other patient as recommended.

Large renal angiomyolipomas: digital subtraction angiographic grading and presentation with bleeding

To investigate whether a grading system of renal AMLs based on digital subtraction angiography (DSA) and computerized tomography (CT), could help to select patients for embolization. Thirty patients with 35 renal angiomyolipomas (size range 4-20 cm, mean 9.9 cm) underwent both digital subtraction angiography (DSA) and computed tomography (CT). Based on the DSA appearance the tumours were graded into three grades: grade I, minimal vascularity; grade II, moderate vascularity; grade III, marked vascularity. There were seven grade I (mean 9.3 cm, range 4.5-20 cm), 18 grade II (mean 8.9 cm, range 5-18 cm) and 10 grade III tumours (mean 12.1 cm, range 4-20 cm). Five grade I tumours did not cause symptoms (71%) and two caused flank pain and haematuria, respectively (14.3% each). Nine of the grade II tumours were asymptomatic (50%), seven caused bleeding (39%) and two caused flank pain (11%). Four grade III tumours were asymptomatic (40%), five caused bleeding (50%) and one pain (10%). According to our criteria, large angiomyolipomas with minimal vascularity are less likely to bleed, and do not need prophylactic treatment. This needs to be confirmed in larger studies.

LONG-TERM OUTCOME OF TRANSCATHETER EMBOLIZATION OF RENAL ANGIOMYOLIPOMAS DUE TO TUBEROUS SCLEROSIS COMPLEX

Complications from renal angiomyolipomas (AMLs) are common in patients with tuberous sclerosis complex (TSC) and tumors greater than 4 cm are more likely to cause symptoms. AMLs are the most common cause of death in adults with TSC. We present our long-term experience with transcatheter tumor embolization as a definitive treatment for AMLs due to TSC. A total of 16 patients with TSC between 7.5 and 47.2 years old with symptomatic or large (4 to 21 cm) AMLs underwent embolization. Followup consisted of periodic physician visits or telephone contacts and renal imaging. The 16 patients underwent 18 treatment sessions to embolize 27 tumors. There were no intraoperative complications. The post-embolization syndrome occurred in 11 individuals but all responded to medical management. Two individuals had an arterial aneurysm within a tumor. The AML size decreased in the 13 patients who were imaged 3 months after treatment, and the 7 patients who were imaged 3 to 9 years after treatment have shown no tumor regrowth. No renal failure or hemorrhage has developed in patients following embolization. Transcatheter embolization of symptomatic or large AMLs due to TSC prevents hemorrhage and renal loss. The treatment is minimally invasive, preserves renal function, and can be performed multiple times. All of the patients who underwent followup renal imaging after embolization showed decreased AML size, and none of the 16 patients has developed renal loss or renal insufficiency in these individuals. Embolization should be considered the initial treatment of choice for large or symptomatic AMLs.

Giant bilateral renal angiomyolipomas associated with tuberous sclerosis

Renal angiomyolipomas in patients with tuberous sclerosis can be associated with significant morbidity, mostly related to complications from bleeding. We describe a patient with tuberous sclerosis and massive bilateral renal angiomyolipomas (total tumor burden 5500 g) who presented with acute right renal hemorrhage. She was treated with right renal artery embolization followed immediately by right nephrectomy and left partial nephrectomy. The patient had a creatinine nadir of 1.3 mg/dL postoperatively. We demonstrate that nephron-sparing surgery is feasible, even in the setting of very large angiomyolipomas, such as the one presented here, currently the largest such tumor by weight reported.

Radiological parameters of bleeding renal angiomyolipoma.

Angiomyolipomas are rare tumours of the kidney which have a tendency to bleed. We studied the clinical and radiological features of 11 patients from our institution to identify features which may be predictive of a massive haemorrhage. Tumours more than 6 cm in diameter were found to bleed and the demonstration of pseudoaneurysms on contrast CT scanning was associated with massive haemorrhage. We conclude that large angiomyolipomas should be treated to avoid haemorrhage and the detection of pseudoaneurysms should prompt urgent treatment.

Hepatic angiomyolipoma: is fat in the liver friend or foe?

Angiomyolipoma (AML) of the liver is a very uncommon benign neoplasm composed of vessels, muscle, and variable amounts of fat (ranging from 5-90% of the tumor), indistinguishable histologically from renal angiomyolipoma [1]. For the majority of radiologists, knowledge of AML is based upon the renal variety. The radiologic appearance of AML in the kidney, its association with tuberous sclerosis, and its potential for rupture, causing massive retroperitoneal hemorrhage, are well known. However, the fact that AML can involve the liver either in association with tuberous sclerosis or spontaneously is not common knowledge. This is due to the rarity of hepatic AML, limited to only 5-10% of tuberous sclerosis cases and a few cases of spontaneous AML reported (approximately 45, primarily in the pathologic literature). The five papers on hepatic AML included in the current issue of Abdominal Imaging allow us to study with cross-sectional imaging a series of eight new cases, including six spontaneous AMLs and two in association with tuberous sclerosis. This almost doubles the number of published cases with cross-sectional imaging from 12 to 20 and adds three new cases with magnetic resonance imaging (MRI) to a single case [2-13]. If one combines the data from these five papers, there is interesting new information both in the clinical and imaging arenas. It appears that hepatic AMLs are predominately seen in women (all four cases of spontaneous AML and two out of three AMLs in tuberous sclerosis). The clinical picture is, as expected, related to size. Large AMLs are painful, while small ones are discovered incidentally. Interestingly enough, despite the enormous size of some of the AMLs described in this issue of Abdominal Imaging, no rupture has ever been recorded of a hepatic AML. In one of the cases, a patient with tuberous scle-

Elective Embolization for Prevention of Hemorrhage from Renal Angiomyolipomas

Among angiomyolipomas 4 cm or larger, 82%-94% are symptomatic and 50%-60% bleed spontaneously. Up to one-third of patients with these lesions present in shock. The effectiveness of elective embolization was evaluated in the prevention of bleeding from large (> or = 4 cm) angiomyolipomas while sparing the normal renal parenchyma. Five cases from the authors' institution and 21 cases from the literature were reviewed retrospectively. Embolization as the sole means of treatment was effective in 90% of patients over a follow-up period from 2 months to 7 years (mean, 21 months). There were no complications at the authors' institution. Serious procedure-related complications reported in the literature were limited to two cases of aneurysm rupture and two necrotic tumors requiring percutaneous drainage. Embolization of renal angiomyolipomas is safe and well tolerated and may be of benefit in preventing life-threatening hemorrhage.