Congenital Posterior Fossa Malformations

Annika Barnett, MSIII Gillian Lieberman, MD Jan 30-Feb 24, 2012 Congenital Posterior Fossa Malformations Annika Barnett, Harvard Medical School Year...
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Annika Barnett, MSIII Gillian Lieberman, MD

Jan 30-Feb 24, 2012

Congenital Posterior Fossa Malformations Annika Barnett, Harvard Medical School Year III Gillian Lieberman, MD

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 2

Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Clinical History •

Female G4P1 presenting for full fetal survey at 21 wks • •

h/o gestational diabetes no family h/o genetic disorders

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Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Full Fetal Survey at 21 Wks Axial U/S

•Dilated 4th ventricle •Posterior fossa cyst communicating with 4th ventricle

4 BIDMC, PACS

Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Summary of Findings • • • •

Dilated Fourth Ventricle Absence of cerebellar vermis Enlargement of posterior fossa Findings consistent with a posterior fossa malformation

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Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Differential Diagnosis • Congenital CNS Anomalies – Chiari Malformation – Encephalocele – Holoprosencephaly – Septo-optic dysplasia – Dandy-Walker Malformation

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Annika Barnett, MSIII Gillian Lieberman, MD

Menu of Tests • Fetal Ultrasound • Fetal MRI • Which is better?

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Annika Barnett, MSIII Gillian Lieberman, MD

MRI vs. U/S • Study at Brigham and Women’s Hospital compared diagnosis of fetal anomalies with MRI vs. U/S • Compared diagnosis of 27 fetuses with anomalies • 57% of the cases involved CNS anomalies • In 62% of those cases, both modalities correctly diagnosed the anomaly • MRI provided additional information (such as agenesis of corpus callosum) in half of those cases • Concluded that MRI may be value as an adjunct to U/S in evaluating CNS anomalies Frates M C et al. Radiology 2004;232:398-404 8

Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Diagnosis Findings on ultrasound were consistent with Dandy-Walker Malformation

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Annika Barnett, MSIII Gillian Lieberman, MD

Now that we have a diagnosis, lets find out more about Dandy-Walker Complex

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Annika Barnett, MSIII Gillian Lieberman, MD

Dandy-Walker Complex • Malformation of posterior fossa – Pathogenesis unknown but thought to be due to arrest of development of hindbrain around 7-10 week gestation

• Spectrum of disease that includes: – – – –

Dandy-Walker malformation Dandy-Walker variant Mega Cistern Magna Posterior Fossa Arachnoid Cyst

• Occurs in 1:30,000 births • Seen in 4-12% of all babies with hydrocephalus 11

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 12

Annika Barnett, MSIII Gillian Lieberman, MD

Dandy-Walker Malformation –

Triad of Malformations • • •



Cystic dilation of fourth ventricle Complete or partial agenesis of the cerebellar vermis Enlarged posterior fossa with displacement of the tentorium and torcular and lateral sinus

Diagnosed after 18 weeks – closure of cerebellar vermis should happen by that time 13

Annika Barnett, MSIII Gillian Lieberman, MD

We now know how to recognize Dandy-Walker Malformations. Let’s look at some classic examples on Ultrasound and MRI

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 2: Dandy-Walker Malformation on Ultrasound Axial

Sagittal

Posterior fossa cyst communicating with dilated 4th ventricle

Courtesy of Dr. Debenedectis

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 3: Dandy Walker Malformation on Ultrasound Axial

Sagittal

Posterior fossa cyst communicating with dilated 4th ventricle 16 Courtesy of Dr. Debenedectis

Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 4: Dandy Walker Malformation On U/S and MRI Axial

T2/C-/Axial

Posterior fossa cyst communicating with dilated 4th ventricle Kolble N et al. Prenatal Diagnosis 2000; 20:318-327 17

Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 5: Dandy-Walker Malformation on MRI T1/C-/Sagittal

T1/C-/Axial

•Dilated 3rd ventricle •Posterior fossa cyst communicating with dilated 4th ventricle •Agenesis of corpus callosum Poe L B et al. Radiographics 1989; 9:801-826

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 6: Dandy-Walker malformation on MRI T2/C-/Sagittal

•Normal corpus callosum •Posterior fossa cyst displacing cerebellum and tentorium Levine D et al. Radiology 1999;211:609-617

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 7: Dandy-Walker on MRI T2/C-/Coronal

T2/C-/Axial

•Posterior fossa cyst communicating with dilated 4th ventricle •Ventriculomegaly Courtesy of Dr. Debenedectis

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Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 21

Annika Barnett, MSIII Gillian Lieberman, MD

Dandy-Walker Variant – Cerebellar dysgenesis without enlargement of the posterior fossa – Variable hypoplasia of the cerebellar vermis – Better prognosis

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 8: Dandy-Walker Variant on U/S Axial

Cleft of cerebellar vermis

Ecker J L et al. Prenatal Diagnosis 2000;20:328-332

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 9: Dandy-Walker variant on Ultrasound Axial Cleft of cerebellar vermis

24 Frates M C et al. Radiology 2004;232:398-404

Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 10: Dandy-Walker variant on MRI T2/C-/Axial Cleft of cerebellar vermis

25 Frates M C et al. Radiology 2004;232:398-404

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 26

Annika Barnett, MSIII Gillian Lieberman, MD

Mega Cisterna Magna • Enlarged posterior fossa caused by enlarged cisterna magna • Cisterna magna drains fourth ventricle • Cerebellum and fourth ventricle are normal • Treated with cisternotomy

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Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 11: Mega Cisterna Magna on MRI T1/C-/Sagittal

Mega Cisterna Magna visualized as a retrocerebellar fluid collection 28 Hamid HA. Egypt Journal of Human Genetics 2007;8:115-120.

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 29

Annika Barnett, MSIII Gillian Lieberman, MD

Posterior Fossa Arachnoid Cyst • Retrocerebellar arachnoid cyst that displaces cerebellum anteriorly • Causes mass effect on cerebellum and fourth ventricle • Looks similar to Mega Cisterna Magna on MRI – Differentiate the two with ventriculogram (Mega Cisterna Magna communicates with subarachnoid space)

• Treated with marsupialization of cyst 30

Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 9: Posterior Fossa Arachnoid Cyst on MRI T1/C-/Sagittal

Posterior fossa cyst causing compression of cerebellum and fourth ventricle 31 Hamid HA. Egypt Journal of Human Genetics 2007;8:115-120.

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 32

Annika Barnett, MSIII Gillian Lieberman, MD

Potential Causes – – – –

Chromosomal Aneuploidy Sporadic Mutation Environment Exposure – Alcohol, Rubella Multifactorial etiology

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Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 34

Annika Barnett, MSIII Gillian Lieberman, MD

Associated Anomalies • Intracranial – Ventriculomegaly (Seen in companion pt. 7) – Agenesis of Corpus Callosum (Seen in companion pt. 5)

• Extracranial – Cardiac Defects (most common) – Renal Abnormalities – Facial Abnormalities – Extremity abnormalities 35

Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Hydronephrosis on Ultrasound Coronal

Right and Left kidney with dilated calyces

36 BIDMC, PACS

Annika Barnett, MSIII Gillian Lieberman, MD

Companion Patient 10: Micrognathia associated with a Dandy-Walker variant on Ultrasound Sagittal

37 Mernagh J R et al. Radiographics 1999;19:S229-S241

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 38

Annika Barnett, MSIII Gillian Lieberman, MD

Prognosis • Variable and hard to predict – Some have mental and physical handicaps while others develop normally – ~25% mortality rate – mostly due to associated anomalies – Prognosis worse in children with chromosomal aneuploidy and associated anomalies

• Treatment aimed at control of hydrocephaly 39

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 40

Annika Barnett, MSIII Gillian Lieberman, MD

Our Patient: Outcome • Amniocentesis was normal • Patient decided not to terminate pregnancy and delivered baby at 35 wks • Received further treatment at Children’s Hospital of Boston Neurology 41

Annika Barnett, MSIII Gillian Lieberman, MD

Agenda • • • • • • • • • • •

Our Patient: History, Findings, and Diagnosis Facts about Dandy-Walker Complex Dandy Walker Malformation Dandy Walker Variant Mega Cisterna Magna Posterior Fossa Cyst Potential Causes Associated Anomalies Prognosis Our Patient: Outcome Summary 42

Annika Barnett, MSIII Gillian Lieberman, MD

Summary • Posterior Fossa Malformations exist in a spectrum of diseases collectively known as the Dandy-Walker complex • Dandy-Walker Malformation is the most severe and involves a triad of malformations easily diagnosed with U/S and MRI • Dandy-Walker complex is associated with many other congenital abnormalities and chromosomal aneuploidy which can be predictive of a worse prognosis 43

Annika Barnett, MSIII Gillian Lieberman, MD

References • Ecker J L et al. The Sonographic Diagnosis of Dandy-Walker and Dandy-Walker Varient: Associated findings and outcomes. Prenatal Diagnosis 2000;20:328-332 • Frates M C et al. Fetal Anomalies: Comparison of MR Imaging and US for diagnosis. Radiology 2004;232:398-404 • Hamid HA. Dandy-Walker Malformation. Egypt Journal of Human Genetics 2007;8:115-120. • Kolble N et al. Dandy-Walker Malformation: Prenatal diagnosis and outcome. Prenatal Diagnosis 2000; 20:318-327 • Levine D et al. Obstetric MRI Imaging. Radiology 1999;211:609-617 • Mernagh J R et al. US Assessment of the Fetal Head and Neck: A State of the Art Pictorial Review. Radiographics 1999;19:S229-S241 • Poe L B et al. Congenital Central Nervous System Anomalies. Radiographics 1989; 9:801-826 44

Annika Barnett, MSIII Gillian Lieberman, MD

Acknowledgments • Dr. Monica Agarwal • Dr. Carolynn Debenedectis • Dr. Gillian Lieberman

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