Congenital Posterior Fossa...
Transcript of Congenital Posterior Fossa...
Congenital Posterior Fossa
Malformations
Annika Barnett, Harvard Medical
School Year III
Gillian Lieberman, MD
Jan 30-Feb 24, 2012 Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Our Patient: Clinical History
• Female G4P1 presenting for full fetal
survey at 21 wks
• h/o gestational diabetes
• no family h/o genetic disorders
Annika Barnett, MSIII
Gillian Lieberman, MD
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Our Patient: Full Fetal Survey at 21 Wks
•Dilated 4th
ventricle
•Posterior fossa
cyst
communicating
with 4th
ventricle
Annika Barnett, MSIII
Gillian Lieberman, MD
BIDMC, PACS
Axial U/S
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Our Patient: Summary of Findings
• Dilated Fourth Ventricle
• Absence of cerebellar vermis
• Enlargement of posterior fossa
• Findings consistent with a posterior fossa
malformation
Annika Barnett, MSIII
Gillian Lieberman, MD
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Our Patient: Differential Diagnosis
• Congenital CNS Anomalies
– Chiari Malformation
– Encephalocele
– Holoprosencephaly
– Septo-optic dysplasia
– Dandy-Walker Malformation
Annika Barnett, MSIII
Gillian Lieberman, MD
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Menu of Tests
• Fetal Ultrasound
• Fetal MRI
• Which is better?
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Our Patient: Diagnosis
Findings on ultrasound were consistent with
Dandy-Walker Malformation
Annika Barnett, MSIII
Gillian Lieberman, MD
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Now that we have a diagnosis, lets
find out more about Dandy-Walker
Complex
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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We now know how to recognize
Dandy-Walker Malformations.
Let’s look at some classic
examples on Ultrasound and MRI
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 2: Dandy-Walker Malformation
on Ultrasound
Courtesy of Dr. Debenedectis
Posterior fossa cyst
communicating with
dilated 4th ventricle
Axial Sagittal
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 3:
Dandy Walker Malformation on Ultrasound
Courtesy of Dr. Debenedectis
Posterior fossa cyst
communicating with
dilated 4th ventricle
Axial Sagittal
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 4: Dandy Walker
Malformation On U/S and MRI
Kolble N et al. Prenatal Diagnosis 2000; 20:318-327
Posterior fossa cyst
communicating with
dilated 4th ventricle
T2/C-/Axial Axial
Annika Barnett, MSIII
Gillian Lieberman, MD
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Poe L B et al. Radiographics 1989; 9:801-826
Companion Patient 5: Dandy-Walker
Malformation on MRI
•Dilated 3rd ventricle
•Posterior fossa cyst communicating with dilated 4th ventricle
•Agenesis of corpus callosum
T1/C-/Sagittal T1/C-/Axial
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 6: Dandy-Walker malformation on MRI
Levine D et al. Radiology 1999;211:609-617
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•Normal corpus callosum
•Posterior fossa cyst displacing cerebellum and tentorium
T2/C-/Sagittal
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 7: Dandy-Walker on MRI
Courtesy of Dr. Debenedectis
T2/C-/Coronal T2/C-/Axial
•Posterior fossa cyst
communicating with dilated 4th
ventricle
•Ventriculomegaly
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Dandy-Walker Variant
– Cerebellar dysgenesis without enlargement
of the posterior fossa
– Variable hypoplasia of the cerebellar vermis
– Better prognosis
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 8: Dandy-Walker
Variant on U/S
Ecker J L et al. Prenatal Diagnosis 2000;20:328-332
Cleft of cerebellar vermis
Axial
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 9: Dandy-Walker variant on Ultrasound
Frates M C et al. Radiology 2004;232:398-404
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Cleft of cerebellar vermis
Axial
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 10: Dandy-Walker variant on MRI
Frates M C et al. Radiology 2004;232:398-404
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Cleft of cerebellar vermis
T2/C-/Axial
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 11: Mega Cisterna
Magna on MRI
Hamid HA. Egypt Journal of Human Genetics 2007;8:115-120.
T1/C-/Sagittal
Mega Cisterna Magna
visualized as a
retrocerebellar fluid
collection
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 9: Posterior Fossa
Arachnoid Cyst on MRI
Hamid HA. Egypt Journal of Human Genetics 2007;8:115-120.
Posterior fossa
cyst causing
compression of
cerebellum and
fourth ventricle
Annika Barnett, MSIII
Gillian Lieberman, MD
T1/C-/Sagittal
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Potential Causes
– Chromosomal Aneuploidy
– Sporadic Mutation
– Environment Exposure – Alcohol, Rubella
– Multifactorial etiology
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Our Patient: Hydronephrosis on Ultrasound
Right and Left kidney
with dilated calyces
Coronal
BIDMC, PACS
Annika Barnett, MSIII
Gillian Lieberman, MD
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Companion Patient 10: Micrognathia associated with a Dandy-Walker variant on
Ultrasound
Mernagh J R et al. Radiographics 1999;19:S229-S241 37
Sagittal
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
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Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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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
Annika Barnett, MSIII
Gillian Lieberman, MD
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Acknowledgments
• Dr. Monica Agarwal
• Dr. Carolynn Debenedectis
• Dr. Gillian Lieberman
Annika Barnett, MSIII
Gillian Lieberman, MD