Contemporary diagnosis and management of renal angiomyolipoma

The Role of Partial Nephrectomy without Arterial Embolization in Giant Renal Angiomyolipoma

Angiomyolipoma is a benign neoplasm composed of varying admixtures of blood vessels, smooth muscle cells, and adipose tissue. Because of an increased risk of spontaneous haemorrhage, surgical approach is needed greater than 4–8 cm size. We here report our partial nephrectomy experience in the 24 cm size giant angiomyolipoma. 26-year-old woman referred to our clinic with a 24 cm size angiomyolipoma in her lower pole of right kidney. The inferior vena cava was deviated to the left by the mass. All the blood tests were normal and we offered her the choices of partial nephrectomy or nephrectomy. Right subcostal approach was used. The patient underwent resection of the mass with a safety region of 1 cm. Frozen section evaluation was consistent with angiomyolipoma and free for surgical margin. Warm ischemia time was 35 min. and intraoperative bleeding volume was 200 cc. Postoperative 2nd day the drain was taken and hospital stay was 4 days. In literature we observed very rare angiomyolipoma cases with such a large dimension treated by partial nephrectomy without arterial embolization. If technically suitable partial nephrectomy is the main chioce in this kind of benign lesions in young patients.

Angiomyolipoma with vascular invasion during pregnancy

Angiomyolipoma (AML) is a rare, benign tumor composed of fat cells, smooth muscle cells, and blood vessels. They are commonly found in the kidney but have also been reported to occur in the liver, ovary, fallopian tube, spermatic cord, palate, and colon. Most often, they are discovered as an incidental finding on computed tomography scan and remain inconsequential; however, certain characteristics such as size, presence of aneurysms, and location can transform this disease process into a life-threatening entity. Here, we describe the case of a 30-year-old pregnant woman with bilateral renal AMLs in which there was invasion of the right renal vein and extension of the tumor into the inferior vena cava. The patient was believed to be at significant risk of hormone-mediated rapid expansion, embolization, and life-threatening pulmonary embolus during the pregnancy and was taken to the operating room for right nephrectomy and removal of the tumor from the vena cava. We report the first case of elective nephrectomy with the removal of the tumor from vena cava complicating pregnancy. The major risks of rupture, spontaneous hemorrhage, renal failure, and tumor thrombus were avoided, thereby demonstrating that despite pregnancy, successful surgery can be performed during the second trimester for the management of complicated AMLs.

Massive retroperitoneal hemorrhage from a giant renal angiomyolipoma treated by selective arterial embolization with an Amplatzer Vascular Plug II

We report on a 36-year-old Caucasian woman who presented to the emergency department with post-traumatic retroperitoneal bleeding diagnosed by computed tomography. After clinical stabilization of the patient, selective arterial embolization was performed. The angiomyolipoma's feeding artery was successfully treated with an 8-mm Amplatzer Vascular Plug Type II. The upper pole of the left kidney, which was supplied by a separate upper renal artery, was conserved. Consequently, the renal angiomyolipoma became necrotic and surgical resection of the entire renal angiomyolipoma was performed. This case illustrates a simple and effective application of an Amplatzer Vascular Plug occluder for vessel embolization, without additional coiling.

Hepatic manifestations of tuberous sclerosis complex: a genotypic and phenotypic analysis

Hepatic manifestations of tuberous sclerosis complex: a genotypic and phenotypic analysis. A retrospective review of the clinical records and radiological images of 205 patients with tuberous sclerosis complex (TSC) was performed to evaluate the prevalence and progression of hepatic lesions; examine the association of hepatic phenotype with genotype, age, and gender; and investigate the relationships between hepatic, renal, and pulmonary involvement. Hepatic angiomyolipomas (AML), cysts, and other benign lesions were identified in 30% of the cohort, and some lesions grew significantly over time. However, no patient had clinical symptoms or complications from hepatic lesions. TSC2 patients exhibited a higher frequency of AML compared to TSC1 patients (p = 0.037), and patients with no mutation identified exhibited a higher frequency of cysts compared to TSC2 patients (p = 0.023). Age was positively correlated with frequency of hepatic involvement (p < 0.001), whereas hepatic phenotype was independent of gender. Presence of hepatic AML was associated with presence of renal AML (p = 0.001). These findings confirm a high rate of asymptomatic hepatic lesions in TSC and further characterize the TSC phenotype.

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

A case of angiomyolipoma of the renal sinus

The case of a 63-year-old woman with a relatively rapidly growing angiomyolipoma (AML) originating from the right renal sinus is presented. The tumor had enlarged to more than fivefold in volume (7.4 × 6.7 × 10.1 cm) in the 7 years following its detection (5.6 × 3.4 × 4.6 cm) and had significantly pushed aside the duodenum and the inferior vena cava. The tumor was surgically resected together with the right kidney, and pathological examination revealed AML originating from the renal sinus. An AML involving or originating from the renal sinus is exceedingly rare; only 14 cases have been reported. Rapidly growing AMLs of the renal sinus are difficult to differentiate from liposarcoma because of similar findings in imaging studies. It should be noted that AML of the renal sinus can be a differential diagnosis of retroperitoneal fatty mass. Furthermore, an enlarged AML in the renal sinus may push aside other organs, such as the ileum, pancreas, and major vessels. Clinicians should determine whether these patients should be placed under active surveillance or be treated with invasive measures, such as radical nephrectomy.

Burden of disease and unmet needs in tuberous sclerosis complex with neurological manifestations: systematic review

OBJECTIVES

Tuberous sclerosis complex (TSC) is a progressive genetic disorder characterized by pervasive benign tumor growth. We sought to assess the current understanding of burden of TSC-related neurological manifestations.

METHODS

We systematically searched MEDLINE- and EMBASE-indexed, English-language literature (5/2000-5/2010) and non-indexed materials.

RESULTS

In total, 119 articles were included, 115 on epidemiology and treatment. Recent prevalence estimates from Ireland and Taiwan report TSC in 1:14,000-25,000 individuals, below older estimates of 1:10,000. While neurological manifestations are common, treatment is largely unaddressed by guidelines and focuses on symptoms, with resection standard for subependymal giant cell astrocytomas (SEGAs) and common practice for refractory epilepsy. Antiepileptic drugs and mammalian target of rapamycin inhibitors safely, effectively minimize the need for surgery for severe epilepsy and SEGAs.

CONCLUSION

Morbidity and treatment burden of prevalent neurological manifestations is significant, suggesting substantial economic and humanistic burden; however, these areas are poorly studied, indicating total disease burden is unknown. Future research should assess quality of life, caregiver burden, and costs.

Clinically relevant imaging in tuberous sclerosis

Tuberous sclerosis (TS), also known as Bourneville disease or Bourneville–Pringle disease, is an autosomal dominant genetic disorder classically characterized by the presence of hamartomatous growths in multiple organs. TS and tuberous sclerosis complex (TSC) are different terms for the same genetic condition. Both terms describe clinical changes due to mutations involving either of the two genes named TSC1 and TSC2, which regulate cell growth. The diagnosis of TSC is established using diagnostic criteria based on clinical and imaging findings. Routine screening and surveillance of patients with TSC is needed to determine the presence and extent of organ involvement, especially the brain, kidneys, and lungs, and identify the development of associated complications. As the treatment is organ specific, imaging plays a crucial role in the management of patients with TSC.

Selective arterial embolization of angiomyolipomas: a comparison of smaller and larger embolic agents

PURPOSE

Selective transarterial embolization for renal angiomyolipomas is effective in preventing or limiting hemorrhage and preserving normal parenchyma. Data are insufficient regarding the safety and efficacy of embolic agents. We compared transarterial embolization of angiomyolipomas using embolic agents of different sizes.

MATERIALS AND METHODS

We performed a retrospective review of all transarterial angiomyolipoma embolizations from 1999 to 2010, and evaluated demographics, procedural data, embolization response and outcomes comparing smaller (less than 150 microns) and larger (more than 150 microns) embolic agents.

RESULTS

Overall 48 patients underwent 66 embolization procedures for 72 angiomyolipomas. Smaller agents were used more commonly (58%). Age, gender, indications, pre-embolization angiomyolipoma size and prevalence of tuberous sclerosis were similar between the groups. Angiomyolipomas decreased a mean±SD 25%±18% after embolization with no differences between the groups (p=0.24). There were 10 angiomyolipomas that required 14 repeat embolizations (median 14 months). Repeat embolization of the same mass was almost sixfold more likely in those embolized with smaller agents (OR 5.88, 95% CI 1.64-20.8, p=0.002). Complications were similar between the groups, although 2 of 3 patients with acute respiratory distress underwent embolization with smaller agents. Patients with tuberous sclerosis had similar angiomyolipoma size, decrease in angiomyolipoma size, followup, complications and need for repeat embolization. Practice patterns changed regarding embolization agent size during the study period.

CONCLUSIONS

Angioembolization with larger embolic agents is associated with higher long-term efficacy compared to smaller agents. Due to concerns for serious pulmonary complications, we no longer use agents smaller than 150 microns. Prospective studies are necessary to evaluate the optimal embolization technique to achieve durable outcomes without increasing patient morbidity.

Prophylactic embolization of renal angiomyolipomas: evaluation of therapeutic response using CT 3D volume calculation and density histograms

PURPOSE

To evaluate the efficacy and tolerance of prophylactic embolization of angiomyolipomas (AMLs) and to analyze the therapeutic response by using three-dimensional 3D volume calculation and 3D quantification of fatty and angiomyogenic components during computed tomography (CT) follow-up.

MATERIALS AND METHODS

Over a 51-month period, 30 patients with 34 AMLs (mean diameter, 82 mm ± 37; range, 30-173 mm) underwent 37 prophylactic embolization procedures. The protocol included supraselective arterial embolization with a combination of absolute alcohol, microparticles, and coils. Mean clinical and imaging follow-up were 20.5 and 14.5 months, respectively. The 3D volume calculation and density histograms were retrospectively analyzed for treatment evaluation.

RESULTS

Four technical failures were observed (11%), with one successful secondary reattempt, resulting in 31 AMLs (91.2%) being embolized. Thirty (88.2%) had CT follow-up and were included in the analysis. Embolization was complete after a single procedure for 25 AMLs (83%) and required two procedures in two cases. Three AMLs had incomplete embolization and were scheduled for a second procedure. Mean volume reductions were 43% ± 32 for AMLs followed for 1-6 months after embolization and 81% ± 19 for the 12 AMLs followed for more than 1 year. The volume reduction after embolization was significantly correlated with the AML initial composition, with fat-rich AMLs showing a much smaller reduction of size than predominantly angiomyomatous AMLs (P < .05).

CONCLUSIONS

Prophylactic embolization allows significant reduction of AML volume with a high success rate. Three-dimensional CT volume and density histogram calculations suggest that it is especially effective on angiomyogenic components and fat-poor AMLs.

Transradial embolization of a bleeding renal angiomyolipoma

Renal angiomyolipoma (AML) is a benign neoplasm with a propensity to bleed among patients with tumors exceeding 4 cm in diameter but can be effectively treated with transarterial embolization to arrest or prevent hemorrhage. We report the use of transradial approach to embolize a bleeding AML in a pregnant patient in order to minimize pelvic radiation. This case illustrates the utility of transradial access as an access approach for performing superselective visceral embolization when a femoral approach is undesirable or not possible.

Benign renal angiomyolipoma with inferior vena cava thrombosis

OBJECTIVE

To present a new case of an uncommon complication of a benign renal tumor. To our knowledge, there are only few published cases of benign renal angiomyolipoma (AML) presenting with tumor thrombus in females. Epithelioid angiomyolipoma is a recently described rare variant of renal angiomyolipoma. It can occur in patients with or without tuberous sclerosis, and may potentially be malignant. Benign renal angiomyolipoma AML rarely presents with evidence of extension into the renal vein, inferior vena cava (IVC) or atrium. We report a case of a benign renal AML with a tumor thrombus to the IVC in a 46-year-old female who presented with right-sided flank pain associated with a right sided abdominal mass.

METHODS

Right Radical nephrectomy with IVC tumor thrombectomy.

RESULTS

Patient is totally asymptomatic. At 1 month after surgery, an abdominal ultrasound showed no evidence of thrombus within the IVC. CT scan of the abdomen at 3 months post-operatively showed no evidence of recurrence.

CONCLUSION

Surgical treatment of angiomyolipoma with IVC thrombus is warranted in view of risk of malignancy and to prevent tumor embolus to the heart or lungs.

Spontaneous perirenal hemorrhage: what radiologists need to know

Spontaneous perirenal hemorrhage (SPH), also known as Wünderlich's syndrome, is a rare urological emergency. This article reviews the most common causes of SPH and the role of imaging in establishing the correct diagnosis and in guiding the appropriate therapy. A thorough understanding of underlying etiologies, imaging appearances, optimal imaging techniques, and follow-up protocols are crucial to recognize patients with SPH due to benign disease and avoid unnecessary nephrectomies.

Life-threatening rupture of a renal angiomyolipoma in a patient taking over-the-counter horse chestnut seed extract

BACKGROUND

Alternative medical therapies are increasingly being prescribed due to their good safety profile and perceived limited side effects. They are often unregulated and prescribed over the counter. One such medication is horse chestnut seed extract (HCSE), which is used for the treatment of chronic venous insufficiency and is known to affect blood coagulation. Angiomyolipoma (AML) is a benign fat-containing mesenchymal tumor of the kidney. It is often found incidentally and in most cases can be managed conservatively. Rupture of the kidney with hemorrhage is a well-known complication that may be serious and life-threatening. Known risk factors for hemorrhage include anticoagulation as well as pregnancy, increased size of the lesion, high lesion vascularity, and aneurysm formation within the tumor.

OBJECTIVES

The aim is to raise awareness of potential HCSE-induced anticoagulation, including, as in the case presented, acute renal AML hemorrhage.

CASE REPORT

The case of a patient taking HCSE for venous insufficiency is presented. The patient suffered a life-threatening rupture of the kidney in the presence of known renal AML. She underwent emergency embolization with a successful outcome. Because HCSE-containing products are thought to be generally safe in the treatment of chronic venous insufficiency, it is important to be mindful of their potential anticoagulant properties and, therefore, their relative contraindication both in patients taking other anticoagulants and those with known renal AML.

CONCLUSION

We demonstrate a potentially life-threatening association between HSCE-containing products and renal AML, highlighting the risk associated with HSCE-induced anticoagulation.

Wunderlich's Syndrome in a Tuberous Sclerosis Patient

Spontaneous non-traumatic renal hemorrhage known as Wunderlich's syndrome is known to occur in renal angiomyolipoma and may be the first manifestation of the disease. Angiomyolipomas in tuberous sclerosis are usually bilateral and multicentric. A 25yr old female, a case of Tuberous sclerosis with bilateral renal angiomyolipomas presented with right loin pain of increasing severity. On evaluation she had acute abdomen with increasing abdominal distension. Investigations revealed large right perinephric hematoma with bilateral renal angiomyolipomas. Exploratory laparotomy and right nephrectomy was done. Spontaneous hemorrhage in renal angiomyolipoma in a case of tuberous sclerosis and management are discussed.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s12262-010-0231-0) contains supplementary material, which is available to authorized users.

Conservative management of a retroperitoneal hemorrhage following a ruptured renal angiomyolipoma in pregnancy

Retroperitoneal hemorrhage following ruptured renal angiomyolipoma is usually managed surgically or by embolization. But when the same episode occurs in pregnancy, surgery which predisposes to preterm delivery and its subsequent sequelae, the unknown influences of radiation exposure on the fetus makes the management of such cases very challenging. A 21-year-old woman was seen in the emergency unit at the 25th week of her pregnancy with complaints of sudden onset left flank pain radiating to the back, nausea and hematuria. Abdominal magnetic resonance imaging (MRI) revealed masses consistent with angiomyolipoma in the upper pole of the left kidney with evidence of recent bleeding and the center of the right kidney measuring 11.5 × 9.5 cm and 3.5 cm, respectively. The patient received three units of red blood cell concentrate due to fall in hematocrit level resulting in hemodynamically stable condition until term. At term, an infant weighing 3510 g was delivered through elective cesarean section. To avoid iatrogenic preterm delivery and unnecessary fetal exposure to radiation, conservative management of ruptured angiomyolipoma in pregnancy may be considered as a treatment option in hemodynamically stable patients.

Comparison of 3D two-point Dixon and standard 2D dual-echo breath-hold sequences for detection and quantification of fat content in renal angiomyolipoma

PURPOSE

To assess the utility of a 3D two-point Dixon sequence with water-fat decomposition for quantification of fat content of renal angiomyolipoma (AML).

METHODS

84 patients underwent renal MRI including 2D in-and-opposed-phase (IP and OP) sequence and 3D two-point Dixon sequence that generates four image sets [IP, OP, water-only (WO), and fat-only (FO)] within one breath-hold. Two radiologists reviewed 2D and 3D images during separate sessions to identify fat-containing renal masses measuring at least 1cm. For identified lesions subsequently confirmed to represent AML, ROIs were placed at matching locations on 2D and 3D images and used to calculate 2D and 3D SI(index) [(SI(IP)-SI(OP))/SI(IP)] and 3D fat fraction (FF) [SI(FO)/(SI(FO)+SI(WO))]. 2D and 3D SI(index) were compared with 3D FF using Pearson correlation coefficients.

RESULTS

41 AMLs were identified in 6 patients. While all were identified using the 3D sequence, 39 were identified using the 2D sequence, with the remaining 2 AMLs retrospectively visible on 2D images but measuring under 1cm. Among 32 AMLs with a 3D FF of over 50%, both 2D and 3D SI(index) showed a statistically significant inverse correlation with 3D FF (2D SI(index): r=-0.63, p=0.0010; 3D SI(index): r=-0.97, p<0.0001).

CONCLUSION

3D two-point Dixon sequence may provide a reasonable alternative to 2D dual-echo sequence for detection of renal AML and may have additional value for quantification of fat content of these lesions given the observation that 3D FF, unlike 2D and 3D SI(index), is not limited by ambiguity of water or fat dominance. This may assist clinical management of AML given evidence that fat content predicts embolization response.

Renal mass sampling: an enlightened perspective

Renal mass sampling (RMS) can be carried out by core biopsy or fine needle aspiration with each presenting potential advantages and limitations. The literature about RMS is confounded by a lack of standardized techniques, ambiguous terminology, imprecise definitions of accuracy, substantial rates of non-informative biopsies, and recurrent diagnostic challenges with respect to eosinophilic neoplasms. Despite these concerns, RMS has an expanding role in the evaluation and treatment of renal masses, in order to stratify biological aggressiveness and guide management that can range from surgery to active surveillance. Non-informative biopsies can be managed with surgical excision or repeat biopsy, with the latter showing encouraging results in recent studies. We propose a new classification in which all biopsies are categorized as non-informative versus informative, with the latter being subclassified as confirmed accurate, presumed accurate or confirmed inaccurate. This terminology will facilitate the comparison of results from various studies and stimulate progress. Incorporation of novel biomarkers and molecular fingerprinting into RMS protocols will likely allow for more rational management of patients with renal masses in the near future.

Trends of presentation and clinical outcome of treated renal angiomyolipoma

PURPOSE

The purpose of this study is to set guidelines for the management of renal angiomyolipoma (AML), clinical prognosis according to tumor size, in association with tuberous sclerosis complex (TSC), multiplicity, radiographic finding, and treatment modality.

MATERIALS AND METHODS

Between March 1998 and October 2008, 129 out of 254 patients with AML who underwent surgical intervention or angioembolization were enrolled. Diagnosis of AML was determined by the presence of a low attenuated component on CT imaging or by pathological confirmation. Indications of treatment were intractable pain, hematuria, suspicion of malignancy, large tumor size, spontaneous rupture, and radiographically equivocal tumors in which a differential diagnosis was needed to rule out malignancy. Parameters including age, sex, tumor size, multiplicity, radiographic characteristics, association with TSC, and treatment modality were reviewed.

RESULTS

Age at presentation was 50.6 years and mean tumor size was 3.5 cm. Presentation symptoms were flank pain, hematuria, spontaneous rupture, and fatigue. 97 (75.2%) patients were incidentally discovered. 100 (77.5%) were females. 68 (52.7%) underwent nephron-sparing surgery (NSS), 35 (27.1%) radical nephrectomy, and 26 (20.2%) angioembolization. TSC was accompanied in 12 (9.3%) patients. No patient developed renal function impairment during the mean follow-up period of 64.8 months. Patients with TSC presented at a younger age, along with larger, bilateral, and multiple lesions.

CONCLUSION

Significant differences in clinical manifestations and treatment outcomes were noted in respect to tumor characteristics, association with TSC, and treatment modality. Considering the benign nature of AML, these parameters ought to be considered when deciding upon active surveillance or prophylactic intervention.

[Contribution of curative and preventive embolization for renal angiomyolipomas treatment]

OBJECTIVE

The purpose of this study was to present the role of embolization in the treatment of kidney angiomyolipomas (AML), for preventive care or in case of bleeding.

METHODS

From March 1995 to March 2007, 22 AML in 21 patients (16 women and five men, mean age 38 years) were embolized: five AML were treated for hemorrhagic shock emergency and 16 were preventive embolization. Eight AML were discovered incidentally and nine patients had pain or hematuria. The average size of AML was 70 mm (20 to 130 mm). The embolization was performed with coils or embospheres.

RESULTS

Three patients have not been embolized because of renal failure catheterization. The embolization was effective in 100% of patients treated in emergency. The six patients cared for gross hematuria and pain were asymptomatic after embolization. The average tumor size reduction was 32% with a mean time of 53.2 months (five to 101 months). Three patients (14%) have benefited from surgery remotely.

CONCLUSION

Embolization is the best technique for treating bleeding secondary to AML. In preventive treatment or symptomatic, AML embolization is a treatment to offer before considering surgery.

[Renal angiomyolipoma with inferior vena cava extension]

Angiomyolipoma is generally a benign and noninvasive tumor. We report a case of angiomyolipoma with tumor thrombus from the renal vein into the inferior vena cava suggesting a malignant disease.

Embolization of giant renal angiomyolipomas: technique and results

PURPOSE

To evaluate the efficacy and safety of prophylactic embolization of angiomyolipomas (AMLs) larger than 10 cm.

MATERIALS AND METHODS

Sixteen patients (mean age, 41.2 years; 14 women and two men) underwent embolization for 23 AMLs larger than 10 cm. All lesions were embolized by using microcatheters with ethanol and ethiodized oil mixed to a ratio of 7(ethanol) to 3(ethiodized oil). Data collected included pre- and posttreatment AML size, creatinine level, technical success, volume of embolic material used, clinical success, and complications.

RESULTS

The mean AML size before treatment was 15 cm (range, 10-25 cm). Ten of the 16 patients (62%) had all their AMLs treated in one session, whereas six (38%) required multiple sessions. A mean volume of 8.6 mL of the ethanol-ethiodized oil mixture (range, 2-20 mL) was administered per lesion. Patients were followed up for a mean of 29 months (range, 1-80 months). No patient had an increase of 0.2 mg/dL (17.7 mumol/L) or greater in mean serum creatinine level during the follow-up period. Two of the 16 patients (12%) required repeat embolization due to AML regrowth (n = 1) or reperfusion (n = 1) seen at surveillance imaging. One of the 16 patients (6.2%) had an AML hemorrhage 59 months after AML embolization.

CONCLUSIONS

Embolization of giant renal AMLs to decrease the risk of bleeding can be done safely without loss of renal function. Although recurrence was infrequent, additional treatment may be necessary and giant renal AMLs should be followed up with serial imaging studies.

Renal angiomyolipoma associated with inferior vena cava thrombus

A 57-year-old woman was found to have an inferior vena cava involvement of a known sinusal angiomyolipoma incompletely resected three years beforehand. Intravascular extension into the IVC of angiomyolipoma has rarely been reported. We present a new case and reconsider the literature about this uncommon complication of a benign renal tumor.

The management of renal angiomyolipomas in a patient with tuberous sclerosis

BACKGROUND

A 17-year-old girl, who was diagnosed with tuberous sclerosis in infancy, presented with multiple bilateral renal masses, the largest of which was 6.0 cm in diameter on the left side.

INVESTIGATIONS

History and physical examination, ultrasonography, MRI, CT, magnetic resonance angiography, and measurement of serial creatinine levels.

DIAGNOSIS

Bilateral angiomyolipomas.Management Observation, serial imaging, embolization and infarction.

The radiological diagnosis and treatment of renal angiomyolipoma-current status

Angiomyolipomas (AMLs) are the most common benign renal neoplasm and are often discovered incidentally. Due to both an increase in the use of imaging, as well as advances in imaging technology, they are being increasing identified in the general population. As these lesions are benign, there is good evidence that the majority of them can be safely followed up without treatment. However, there is an increasing wealth of information available suggesting there are individuals with AMLs where prophylactic treatment is indicated to prevent complications such as haemorrhage. In such cases, treatment with radiological interventional techniques with subselective particle embolization has superseded surgical techniques in most cases. Even in emergency cases with catastrophic rupture, prompt embolization may save the patient with the additional benefit of renal salvage. Confident identification of a lesion as an AML is important as its benign nature obviates the need for surgery in most cases. The presence of fat is paramount in the confirmatory identification and characterization of these lesions. Although fat-rich AMLs are easy to diagnose, some lesions are fat poor and it is these cases where newer imaging techniques, such as in-phase and out-of-phase magnetic resonance imaging (MRI) may aid in making a confident diagnosis of AML. In this paper, we comprehensively review the imaging techniques in making a diagnosis of AML, including features of both characteristic lesions as well as atypical lesions. In addition, we discuss current guidelines for follow-up and prophylactic treatment of these lesions, as well as the increasing role that the interventional radiologist has to play in these cases.

Angiomyolipoma of the colon: report of a case

Angiomyolipomas are benign mesenchymal tumors mostly arising from the kidney. Angiomyolipoma of the colon is extremely rare. Here we report the findings of a 51-year-old man who presented with a submucosal tumor covered with normal mucosa and hemorrhage in the descending colon. He underwent a partial resection of the descending colon. A histopathological examination showed that the tumor of 5.7 cm in diameter included smooth muscle (spindle cell type), mature adipose tissue, and vessels, and therefore a diagnosis of angiomyolipoma was made. A submucosal type of angiomyolipoma of the colon is extremely rare. If a renal angiomyolipoma is larger than 4 cm, there is a risk of rupture. When colonoscopy shows a submucosal tumor of the colon with hemorrhage, angiomyolipoma should be considered. If an angiomyolipoma of the colon is large, surgical resection should be considered as a treatment option due to the risk of hemorrhage.

Polycythemia vera as a presentation of renal angiomyolipoma: a case report

INTRODUCTION

Angiomyolipoma is a common benign renal tumor composed of thick-walled blood vessels, smooth muscle, and adipose tissue. It may be found incidentally during workup for suspected renal disease. Although angiomyolipoma may present as a palpable, tender renal mass with flank pain and gross or microscopic hematuria, many patients are asymptomatic. Erythrocytosis is an unusual presentation, and malignant transformation may be suspected. This report describes a rare case of a woman diagnosed with renal angiomyolipoma and polycythemia vera. The report discusses the differential diagnosis using erythropoietin, erythropoietin-receptor and Janus kinase 2.

CASE PRESENTATION

A 79-year-old Chinese woman was diagnosed with erythrocytosis according to World Health Organization criteria. An upper left renal pole angiomyolipoma was successfully ablated after multiple phlebotomy treatments. Red cell count immediately returned to normal, but gradually increased after 4 months. Polycythemia vera was finally diagnosed by positive mutation of Janus kinase 2 and negative erythropoietin protein expression. Her clinical symptoms improved with regular phlebotomy and hydroxyurea treatment.

CONCLUSION

Concurrent occurence of angiomyolipoma and polycythemia vera is rare. Polycythemia vera can be easily missed. Polycythemia vera can be confirmed with high specificity and sensitivity by the acquired somatic mutation. Surgical intervention for this renal tumor should be avoided unless malignancy or renal cell carcinoma is suspected or to prevent spontaneous rupture of larger tumors.

Long-term follow-up of the treatment of renal angiomyolipomas after selective arterial embolization with alcohol

STUDY TYPE

Therapy (case series).

LEVEL OF EVIDENCE

4.

OBJECTIVE

To present our institution's experience of selective embolization of renal angiomyolipomas with alcohol and the long-term follow up data.

PATIENTS AND METHODS

This retrospective study included 34 patients treated between October 1997 and October 2007 (29 women and five men, mean age 44 years). Of these patients, nine had tuberous sclerosis, 14 were bilateral and 16 were multifocal. Indications for treatment were previous haemorrhage (14), size >4 cm (19) and increasing size over a short period (one). The largest treated lesion was 24.4 cm, and the mean (range) size was 11.9 (2.9-24.4) cm. All patients were treated by selective embolization using a mixture of alcohol and lipiodol. Three patients also had coiling of aneurysms and two patients had additional embolization with polyvinyl alcohol particles. The follow-up was both radiological and clinical, with recurrence defined as growth by >2 cm or symptoms requiring further treatment.

RESULTS

The technical success rate was 100%, with only one significant complication of non-target renal embolization, with self-limiting effects. Minor complications included 11 patients with post-embolization syndrome, all of which settled with conservative measures. The mean (range) combined radiological and clinical follow-up was 44.2 (12-116) months, with all patients having a follow-up of >1 year. Radiological success was achieved in 97%, with only one lesion growing by >2 cm. The combined clinical and radiological success rate was 85%, with two patients undergoing surgery, two having repeat embolization and one currently offered surgery due to a recent increase in size.

CONCLUSION

Our study provides long-term evidence that selective arterial embolization with alcohol is a safe and effective method for improving clinical symptoms (85%) and preventing tumour progression (97%) in patients with renal angiomyolipoma.

Pulmonary edema as a complication of transcatheter embolization of renal angiomyolipoma in a patient with pulmonary lymphangioleiomyomatosis due to tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal-dominant disorder characterized by seizures, mental retardation, and various hamartomatous lesions, including renal angiomyolipoma (AML) and pulmonary lymphangioleiomyomatosis. A 22-year-old woman with TSC presented with multiple renal AMLs exceeding 4 cm in diameter. She underwent two transcatheter embolization procedures with a mixture of ethanol and iodized oil. She complained of dyspnea and minor hemoptysis 4 and 6 hours after the procedure. Findings on chest radiographs and computed tomographic images were indicative of pulmonary edema. The patient was treated with conservative therapy. The possible causes of the pulmonary edema are discussed in the text.

Urgent angioembolization with early elective nephron-sparing surgery for spontaneously ruptured renal angiomyolipoma

Tumor rupture with hemorrhage is a severe complication of renal angiomyolipoma. Urgent transcatheter arterial embolization is an effective method for the patient suffering from life-threatening hemorrhage due to ruptured angiomyolipoma. Elective surgery has been suggested because of the possibility of rebleeding or abscess formation after embolization. However, it is not easy to perform a nephron-sparing procedure by delayed elective surgery due to severe tissue adhesion after bleeding. Herein, we report 2 cases of ruptured renal angiomyolipoma initially managed with transcatheter arterial embolization. Nephron-sparing surgery was performed a few days after embolization, before tissue adhesion occurred. Both kidneys were preserved, and the postoperative course was uneventful.

Transcatheter embolisation of renal angiomyolipoma

INTRODUCTION

Angiomyolipomas (AML) are rare benign renal tumours which are associated with aneurysms that can cause haemorrhage. Embolisation of AML greater than 4 cm with a variety of embolic agents is now the first-line treatment in these cases.

METHODS

This was a retrospective analysis of all patients who underwent AML embolisation at Beaumont Hospital from 2000 to 2006 to review the efficacy of embolisation in the treatment of AMLs.

RESULTS

There were six patients in total (n = 6). One patient (16%) had a background of tuberous sclerosis. Half of the patients presented acutely with bleeding and abdominal pain (50%) while the other half were found incidentally. There were no mortalities overall and three patients (50%) developed post embolisation syndrome. Five patients (83%) had a good response to embolisation with no further growth or regression of the AML.

CONCLUSION

Embolisation is a safe and effective method for treating patients with AML.

Embolization of renal angiomyolipomas: short-term and long-term outcomes, complications, and tumor shrinkage

This study retrospectively evaluated outcomes, complications, and tumor shrinkage in renal angiomyolipomas after transcatheter arterial embolization (TAE). All renal angiomyolipoma patients who underwent TAE between August 2000 and December 2008 and had short-term (<or=6 months) or long-term (>6 months) follow-up images were evaluated. Complications and tumor relapse after TAE were reviewed. The sizes of embolized tumors were measured to calculate size reductions and reduction rates after TAE. Differences in tumor size, size reduction, and reduction rate between different time points (pre-TAE, short-term follow-up, and long-term follow-up) and groups (completely and incompletely embolized) were determined. Eleven renal angiomyolipoma patients who had undergone TAE were included. Seven (63.6%) patients had postembolization syndrome and one had abscess formation following TAE. Two patients had a tumor relapse (18.2%). The mean tumor size was 8.57+/-2.66 cm on pre-TAE images. The mean size reduction was 3.1 cm (33.3%) and 3.8 cm (43.0%) at short-term and long-term follow-up. Tumor sizes differed significantly between pre-TAE and short-term (p=0.004) or long-term images (p=0.022) but not between short-term and long-term images (p=0.059). Results stratified by the completeness of embolization indicate that only the short-term size reduction rate differed significantly (p=0.025), while the long-term reduction rate and short- and long-term follow-up tumor size and size reduction were comparable between the two groups. In conclusion, selective TAE is effective for tumor shrinkage in most renal angiomyolipomas, with acceptable complication and relapse rates. Tumor shrinkage occurring within 6 months after TAE may reflect the long-term effect of TAE.

T-cell co-regulatory molecule expression in renal angiomyolipoma and pulmonary lymphangioleiomyomatosis

OBJECTIVES

To investigate the expression of B7-H3 and B7-H1 in renal angiomyolipoma (AML) tumors and the related, devastating syndrome of pulmonary lymphangioleiomyomatosis (LAM). We recently reported the high expression of T-cell co-regulatory B7-H ligands in renal cell carcinoma tumor vasculature and tumor cells. AML is a highly vascular tumor that most frequently emanates from the kidney. Events leading to its pathogenesis remain enigmatic and understudied.

METHODS

Immunohistochemical methods were used to assess the tumor expression of B7-H1 and B7-H3 in paraffin-embedded tissues from 110 patients who had undergone partial or radical nephrectomy for renal AML and from 7 patients with LAM who had undergone lung biopsy.

RESULTS

B7-H3 was expressed by 100% of the AML and LAM specimens, and B7-H1 expression was detected in only 2.7% of the specimens studied. Both membranous and cytoplasmic B7-H3 expression was noted in the smooth muscle, blood vessel, and lipoid cell components of the tumors; however, no expression was detected in the adjacent, normal parenchyma tissue. B7-H3 staining was noted in a median of 90% (range 20%-100%) of cells from renal AMLs and was independent of patient age (P = .43), sex (P = .27), tumor size (P = .21), and symptomatic presentation (P = .35).

CONCLUSIONS

B7-H3 was expressed at high levels in renal AMLs and pulmonary LAM, and B7-H1 was infrequently expressed in these tumors. Additional studies are needed to evaluate the utility of B7-H3 as a diagnostic marker or immune/angiogenic target to improve the management of AML and the potentially devastating condition of LAM, for which effective treatment is lacking.

Evaluation of renal function of angiomyolipoma patients after selective transcatheter arterial embolization

BACKGROUND

Angiomyolipoma patients may have renal insufficiency before selective transcatheter arterial embolization (TAE) or may undergo subsequent surgery after TAE. Therefore, this retrospective study examined our experience with TAE or TAE and subsequent surgery on renal function of angiomyolipoma patients with and without preexisting renal insufficiency.

METHODS

25 patients who had undergone TAE for renal angiomyolipoma over a 7-year period were reviewed. The 25 patients were grouped according to whether or not they had undergone further surgery. Preexisting renal insufficiency was compared between the 2 groups. The TAE and surgery group was further subdivided into 2 subgroups according to total nephrectomy or not. The TAE-alone group was further subdivided into 2 subgroups by presence of preexisting renal insufficiency or not. In each group and subgroup, pre-TAE and post-TAE renal function, including serum creatinine and creatinine clearance were compared.

RESULTS

TAE rather than TAE and surgery was more likely chosen in the presence of preexisting renal insufficiency (6/13 versus 1/12, P=0.035). In TAE-alone patients, no statistical differences were noted between serum creatinine and creatinine clearance before and after TAE. Conversely, TAE and surgery patients who had undergone total nephrectomy rather than nephron-sparing surgery differed significantly in preand post-TAE serum creatinine (0.77 versus 1.07, P=0.014) and creatinine clearance (98.1 versus 70.7, P=0.032).

CONCLUSIONS

This study demonstrated that TAE alone for treating renal angiomyolipomas was able to preserve renal function, despite the presence of mild preexisting renal insufficiency. Conversely, surgery after TAE, particularly total nephrectomy, should be avoided whenever possible.

A case report of spontaneous rupture of a renal angiomyolipoma in a post-partum 21-year-old patient

INTRODUCTION

Renal angiomyolipomas (AML) are benign tumours containing vascular, smooth muscle and fatty elements. The majority of renal AML run an asymptomatic, benign course. The main associated complication is that of retro-peritoneal or intra-tumoural haemorrhage. Treatment options include conservative management versus interventional procedures such as total or partial nephrectomy, cryotherapy or embolization.

CASE

We describe a case of symptomatic, spontaneous rupture of AML in the immediate post-partum period of a patient treated under our care.

DISCUSSION

This case highlights the presentation in the form of an acute abdomen in the immediate post-partum period. This is important as acute abdomen following delivery can be attributed to a number of other causes. It also demonstrates that further complications of renal angiomyolipoma rupture can arise, emphasising the importance of post treatment vigilance for signs of infection, further haemorrhage and post embolic events.