Fetal Brain Anomalies Part III

1. Fetal Brain AnomaliesPart III Holoprosencephaly HPE 洪正修主任 楊明智主任 指導 陳志堯醫師

2. HOLO- Holo在希臘文中意為「完全」、「完整」

3. Severe brain malformation due to early arrest in brain cleavage and rotation.

4. Five Cephalons 9+ wks Rhombencephalon Prosencephalon

5. Cerebral hemisphere • Choroid plexus • Internal capsule • Olfactory bulbs and tracts 5th wk Telencephalon Prosencephalon (forebrain) • Thalamus • Optic nerve • Geniculate & mamillary body • Pineal and pituitary glands Diencephalon Neural tube & folds 3~4th wk Mesencephalon (midbrain) Metencephalon Pons, cerebellum Rhombencephalon (hindbrain) Myelencephalon Medulla

7. Three Types of HPE • Alobar • Semi-lobar • Lobar

8. Classification & Features of Holoprosencephaly

9. Alobar Holoprosencephaly

10. Nomenclature for associated facial malformations. • Cyclopia (獨眼畸形併眼畸形) • Ethmocephaly (篩形頭畸胎形) • Cebocephaly (猴頭畸胎形) • Face with median cleft lip

15. 獨角獸 • 神話生物，常見的造型是頭上長角的像白馬的生物。 • 在歐洲大陸的傳說中，獨角獸是純潔的化身，它有時被描繪成雌性，而其角具有解毒的作用。 • 中世紀的神話傳說中，獨角獸自由地徜徉在山間野外，它們對人類十分友好。故事中，單純善良的獨角獸往往被少女的迷人的體香所誘惑，陷入可怕的圈套，「純潔」的少女野蠻地斬下它那神奇的角，失卻魔力的獨角獸只能聽由獵人無情的宰殺。中世紀歐陸不肖商人往往以其他獸角冒充獨角獸角出售。

16. 獨角獸 • 公元前398年，古希臘的歷史學家Ctesias在他的書中寫道：「獨角獸生活在印度、南亞次大陸，是一種野驢，身材與馬差不多大小，甚至更大。他們的身體雪白，頭部呈深紅色，有一雙深藍的眼睛，前額正中長出一隻角，約有半米長。」這隻神秘的角從此流傳了幾個世紀。底部雪白，中間烏黑，頂端鮮紅，獨角獸銳利的角有著奇異的魔力。從角上挫下來的粉末可以解百毒，服下粉末即可抵禦疾病、百毒不侵，更能夠起死回生。魔力令人們對這隻離奇的角發狂，每個貴族都想擁有獨角獸角做的酒杯，每個獵人都妄想有朝一日獨角獸落入他的陷阱。

20. Best Diagnostic Clues • 1st trimester • Absent of butterfly sign: Abnormal appearance of choroid plexus. • 2nd~3rd trimester • Fused thalami with mono-ventricle

21. Ultrasound Findings • Absence of butterfly sign • Single ventricle • Absent midline structures • Fused thalami • Dorsal sac • Remaining brain has 3 appearance • Pancake, Cup, Ball

22. Ultrasound Obstet Gynecol 2000; 15: 62–65

23. Ultrasound Obstet Gynecol 2000; 15: 62–65

24. Ultrasound Obstet Gynecol 2000; 15: 62–65

25. Prenat. Diagn. 19: 859–862 (1999)

26. CY Chen 2007

27. Ultrasound Findings • Absence of butterfly sign • Single ventricle • Absent midline structures • Fused thalami • Dorsal sac • Remaining brain has 3 appearance • Pancake, Cup, Ball

30. Ultrasound Findings • Absence of butterfly sign • Single ventricle • Absent midline structures • Fused thalami • Large dorsal sac • Remaining brain has 3 appearance • Pancake, Cup, Ball

31. Large dorsal sac

32. Ultrasound Findings • Absence of butterfly sign • Single ventricle • Absent midline structures • Fused thalami • Large dorsal sac • Remaining brain has 3 appearance • Pancake, Cup, Ball

34. Pathology • Most sporadic • Trisomy 13, 18, triploid, monosomy 21 • At least 12 different genes involved in HPE • 1:16000 births，1:250 in terminated preg. • Facial malformations of any kind should trigger a very careful of the brain

35. Semi-lobar • Incomplete interhemispheric fissure • Rudimentary cerebral lobes • Olfactory tracts and bulbs absent or hypoplastic • Abnormal corpus callosum • Thalami completely/partly fused

41. Lobar HPE • Interhemispheric fissure present • Well formed cerebral lobes • Abnormal corpus callosum • Thalami normal/partly fused • Fornices fused • Abnormal ACA

45. The most important D/D • Hydrocephalus • Arachnoid/glioependymal cyst

46. Hydrocephalus

47. Hydrocephalus

48. Arachnoid cyst

49. Cystic Neoplasm

50. MRI is VERY HELPFUL!!!