Renal Angiomyolipoma - Lieberman's eRadiologyeradiology.bidmc.harvard.edu/LearningLab/genito/Sandhu.pdf · Mini-Seminar Outline. 1. Renal Angiomyolipoma (AML): Facts 2. Angiomyolipoma:

Renal Angiomyolipoma

Emir S. SandhuHarvard Medical School, Year

IIIGillian Lieberman, MD

Emir Sandhu, HMS IIIGillian Lieberman, MD

Nov-Dec 2011

A Comparison of Sporadic and Genetic Cases

Mini-Seminar Outline1.

Renal Angiomyolipoma

(AML): Facts

2.

Angiomyolipoma: Associated Syndromes3.

Clinical presentation of AMLs

4.

Epidemiology 5.

Overview of Renal Anatomy

6.

Meet Our Patient: Clinical Presentation7.

Our Patient: Diagnostic Workup

8.

AMLs: Role of Angiography9.

Our Patient: Therapeutic Management of AMLs

10.

Companion Patient: Tuberous Sclerosis11.

Tuberous Sclerosis: Facts and Role of Imaging


2

Renal Angiomyolipoma: Facts• Benign renal tumor• 3 major histologic

components, consisting of

mature fat cells, smooth muscle, blood vessels. • Characteristic features including adipose

tissue shown below:

Image: http://path.upmc.edu/cases/case165.html


3

Associated Syndromes: Tuberous Sclerosis

• Neurocutaneous

syndrome• 10% of angiomyolipomas

are associated with

Tuberous Sclerosis • Rare multi-system genetic disease that causes non-

malignant tumor formation, typically manifesting in brain, skin, kidney, heart, eyes, lungs.

• Associated symptoms include seizures, developmental delay, lung and kidney disease.

More to come on Tuberous Sclerosis.


4

Associated Syndromes: Sporadic Lymphangioleiomyomatosis

• Smooth muscle infiltration into alveoli.

• Female predominance.• Often occurs

concurrently with TS. • Rarely can occur

sporadically. 60% of sporadic cases also develop AMLs.

• AMLs

histo- pathologically identical

to those seen in TS.


Images: (Left) High-resolution axial CT revealing cystic parenchymal

changes of LAM. (Right) Renal CT showing multiple lesions (-15 to -100 HU) characteristic of fat.

Images: Bissler

and Kingswood, (2004).

5

Angiomyolipoma:

Clinical Presentation• Most common symptoms are the following:

– Flank pain– Hematuria: may lead to hypotension (parenchymal,

subcapsular, and/or perirenal

hemorrhage)• Underlying Pathology:

– Arteries within AMLs

lack an internal elastic membrane.

– AMLs

have disorganized adventitial smooth muscle. – Progresses to bleeding and aneurysms.


6

AML:

Internal Elastic Membrane


Shown above is an artery in AML (left) compared with a normal artery (right). The AML artery characteristically lacks an internal elastic membrane, surrounded by a collar of myomatous

cells.

Image: Meilstrup

et al, 1995 7

Angiomyolipoma: EpidemiologyBased on a study performed by Fujii

et al in 1995:

• Renal ultrasonography

performed on 17,900 healthy adult patients in Japan.

• Patients had no signs of urinary tract malignancies.• Hyperechoic

renal masses suggestive of angiomyolipoma

found in 41 (0.23%).• Upon further diagnostic confirmation, renal

angiomyolipoma

identified in 24 patients (0.13%)• Stratification by gender reveals approximately 0.1% in

males and 0.22% in females• Separate study of 8501 autopsies demonstrated similar

incidence.


8


Renal Angiomyolipoma: Facts

2.



4.

Epidemiology 5.


6.



8.



10.




9

Renal Anatomy: An Overview


Images: Renal Anatomy at http://biomed.brown.edu. Accessed 12/11/11. 10

http://biomed.brown.edu

Meet Our Patient: Clinical Presentation• 38 year-old female who recently emigrated from

China, initially presents to nephrology clinic.• When in China, patient had an MRI suggesting she

had a benign tumor on her right kidney.• She was referred following renal ultrasound ordered

by her primary care physician, which revealed a cortical-based echogenic

mass in the right kidney,

measuring approximately 3.9 x 3.5 cm, that was causing moderate hydronephrosis.

• On later visit, Urology felt the mass had been stable for the past year, and wanted to repeat MRI in 6 months.


11

Our Patient: Past Diagnostic Workup• 10/2008 MRI: 4.8 x 4.2 cm • 10/2010 MRI: 6.8 x 4.4 cm• 1/2011 Presented to the BIDMC ED with

dull right flank pain. No hematuria, dysuria, or urinary frequency.

• 5/2011: Seen by Urology, no plan for procedure. Follow up in 6 months.

• 10/2011: MRI: 8.9 x 5.7 cm• 11/2011: Decides on intervention.


12

Our Patient: Echogenic

Mass on US


Shown on sagittal

ultrasound of the right kidney is a cortical- based, echogenic

mass measuring 3.9 x 3.5 cm. There is

moderate hydronephrosis

with no evidence of stones.Image: BIDMC PACS

13

Our Patient: Right Kidney Doppler


Shown is a sagittal

ultrasound of the right kidney. Note the poor Doppler flow evident within the renal mass.

Image: BIDMC PACS14

Companion Patient:

AML on CT• Presence of fat in

kidney highly suggestive of AML.

• Fat is -20 to -80 Hounsfield Units (prior to contrast)

• Contrast may be given to reveal aneurysms


Image above: Small AML shown in upper pole of right kidney (arrow), measuring -46

HU on axial CT scan.

Image: Meilstrup

et al. (1995)15

Our Patient: AML on Axial Vibe MRI


On axial MRI: Large 8.9 x 5.7 cm mass centered in lower pole of the R kidney, extending into the R hilum

inferiorly. Diffuse low- grade enhancement seen, consistent with AML. There is also a 4-

mm lesion in the lower pole of the R kidney, also an AML.Image: BIDMC PACS

16

Our Patient: T1 Axial In-Phase MRI


Shown on the left is our patient’s T1 axial, in phase MRI. Note the effect of fat suppression compared with the axial

vibe image shown on the right.

Image: BIDMC PACS 17

Our Patient: T1 Out-of-Phase MRI


On axial out-of-phase MRI, the India Ink Artifact is shown, which represents signal drop-out in voxels

that contain both fat and non-fat components. It is seen surrounding interfaces, as if someone had

outlined the interfaces with ink. A renal AML is also shown.Image: BIDMC PACS

18



2.



4.

Epidemiology 5.


6.



8.



10.




19

AML: Role of Renal Angiography• Not often used to diagnosis

AML• Often used for management

of bleeding• AMLs

have circumferential

peripheral vessels with whorled appearance during nephrographic

phase

• Multiple aneurysms are also characteristic.

• In study by Becker, et al: aneurysms found on 16 of 34 AML cases


Image above: Angiography of R kidney revealing AML of the upper pole with

aneurysms. Image: Meilstrup

et al. (1995) 20

AML: Treatment RecommendationsSteiner Study: 35 patients with AML evaluated.

Recommendations:• Lesions <4cm should be followed with yearly CT/US.• Asymptomatic patient with lesion >4cm should have

semi-annual US.• Symptomatic patient with lesion >4cm should

undergo renal-sparing surgery or arterial embolization.

• Prophylactic intervention for patient with Tuberous Sclerosis and lesion >4cm, irrespective of symptoms.

• Two established treatment options include renal- sparing surgery or embolization.

From: Steiner MS, et al. (1993).


21

Our Patient: AML EmbolizationEmir Sandhu, HMS IIIGillian Lieberman, MD

Based on these treatment recommendations, our patient underwent embolization

of her AML.

-

Particle embolization

was performed to reduce flow rate through AML, closely monitored under fluoroscopic visualization. -Post-emblotherapy

R renal arteriogram demonstrated an avascular

tumor with no detectable venous or arterial flow from an inferior polar branch of the R renal artery.

Images: BIDMC PACS 22

Companion Patient #2: Tuberous Sclerosis

Image: T1-weighted coronal MRI.

Shown to the left in our companion patient are two lesions with increasing signal intensity (arrows) similar to subcutaneous fat (asterisk).

These are compatible with large angiomyolipoma.


Image: Bissler

and Kingswood, (2004).23



2.



4.

Epidemiology 5.


6.



8.



10.Companion Patient: Tuberous Sclerosis

11.



24

Tuberous Sclerosis: Facts• Bilateral renal involvement typical. • 1/3 of cases are familial, remaining sporadic.• Transmitted in an autosomal

dominant trait.

• Characteristic formation of tubers in the skin, brain, kidneys, and other organs.

• Incidence is estimated to be approximately 1 in 6,000 live births.

• Two genes identified, TSC1 and TSC2, located on chromosomes 9 and 16 respectively.


25From: Kumar V, et al. Robbins & Cotran

Pathologic Basis of Disease.(2009).

Tuberous Sclerosis: Diagnostic Criteria

Major Features Minor featuresFacial anglofibromas/forehead plaque Multiple pits in dental enamelNon-traumatic ungual

fibroma Hamartomatous

rectal polypsHypomelanotic

macules Bone cystsShagreen

patch (connective tissue nevus) Cerebral white matter radial migration lines

Multiple retinal nodular hamartomas Gingival fibromasCortical tuber Nonrenal

hamartomasSubependymal

nodule Retinal achromic

patchSubependymal

giant cell astrocytoma “Confetti”

skin lesionsCardiac rhabdomyoma Multiple renal cystsLymphangiomyomatosisRenal angiomyolipoma

Definitive diagnosis: 2 major features OR 1 major + 2 minor features required.


26From: Roach ES, et al. (1999).

Tuberous Sclerosis: Renal Manifestation

• Most common TS manifestation is the formation of angiomyolipomas.

• Benign cysts and (less often) lymphangiomas

can also occur in patients with TS.

• Both cysts and angiomyolipomas

tend to present bilaterally.

• Many patients, however, have no symptoms referable to the kidney.


27From: Casper KA, et al. (2002).

Tuberous Sclerosis: Role of Imaging• Renal US should be performed at time of diagnosis to define

extent of angiomyolipomas

and/or presence of polycystic disease.

• US recommended every 1-3 years to monitor growth of lesions and possible signs of malignancy. – Ex: of concern would be a non-cystic mass lacking low

density (-10 to -100 HU) to suggest benign AML.

• If malignant transformation suspected or large angiomyolipoma(s) present: – CT or MR recommended to evaluate abnormality.– Avoid gadolinium based imaging in those with GFR < 30

mL/min given risk of nephrogenic

systemic fibrosis.


28From: Roach ES, et al. (1999).

Tuberous Sclerosis: Renal Complications• Angiomyolipomas

can become quite large, leading to

abdominal or flank pain, bleeding into lesion (typically when > 4 cm diameter)

• Renin-dependent hypertension, due to focal areas of ischemia around lesions. Chronic renal failure also can occur.

• RCC also is a known complication. Occurs in 1-2% of patients, substantially lower than VHL syndrome. – Histology is usually consistent with clear cell carcinoma.


29

From: Steiner MS, et al. (1993).Rakowski

SK, et al. (2006).

Summary of Learning ObjectivesIn this mini-seminar, we have covered the following

topics:– Renal Angiomyolipoma:

• Clinical presentation• Associated genetic syndromes• Diagnostic evaluation• Relevant imaging findings• Therapeutic management

– Tuberous Sclerosis: • Clinical presentation• Renal manifestations and complications• Role of imaging and diagnostic criteria


30

References1.

Bissler

JJ, Kingswood, JC. Renal angiomyolipomata. Kidney Int. 2004 Sep;66(3):924-

34.

2.

Becker JA, et al. Angiomyolipoma

(hamartoma) of the kidney: An angiographic review. Acta Radiol Diagn. 1973 Sep;14(5):561-568.

3.

Brown University. Brown L, et al. The Past, The Present and The Future of Dialysis: Renal Anatomy. Accessed December 11, 2011. http://biomed.brown.edu/Courses/BI108/BI108_2001_Groups/WAK/renalphys/renalana

tomy.html.

4.

Casper KA, et al. Tuberous sclerosis complex: renal imaging findings. Radiology. 2002 Nov;225(2):451-6.

5.

Kumar V, et al. Robbins & Cotran

Pathologic Basis of Disease. 8th ed. Philadelphia, PA: Saunders Elsevier; 2009.

6.

Lemaitre L, et al. Imaging of angiomyolipomas. Semin Ultrasound CT MR. 1997 Apr;18(2):100-14.

7.

Meilstrup

JW, et al. Other renal tumors. Semin Roentgenol. 1995 Apr;30(2):168-84.8.

O’Callaghan FJ, et al. An epidemiological study of renal pathology

in tuberous sclerosis complex. BJU Int. 2004;94(6):853.

9.

Rakowski

SK, et al. Renal manifestations of tuberous sclerosis complex: Incidence, prognosis and predictive factors. Kidney Int. 2006;70(10):1777.

10.

Roach ES, et al. Tuberous Sclerosis Consensus Conference: recommendations for diagnostic evaluation. National Tuberous Sclerosis Association. J Child Neurol. 1999 Jun;14(6):401-7.

11.

Steiner MS et al: The natural history of renal angiomyolipoma. J Urol. 1993;150:1782. 31

http://biomed.brown.edu/Courses/BI108/BI108_2001_Groups/WAK/renalphys/renalanatomy.html

AcknowledgementsI would like to extend a warm thank you to the

following people for their help with my presentation:

Dr. Gillian LiebermanDr. Samir

Shah

Claire OdomMy fellow medical students

32

Documents

Renal Angiomyolipoma - Lieberman's eRadiologyeradiology.bidmc.harvard.edu/LearningLab/genito/Sandhu.pdf · Mini-Seminar Outline. 1. Renal Angiomyolipoma (AML): Facts 2. Angiomyolipoma: