TY  - CHAP
M1  - Book, Section
TI  - Exencephaly/Acrania
A1  - Bianchi, Diana W.
A1  - Crombleholme, Timothy M.
A1  - D'Alton, Mary E.
A1  - Malone, Fergal D.
PY  - 2015
T2  - Fetology: Diagnosis and Management of the Fetal Patient, 2e
AB  - Key  PointsRare  fetal  anomaly  that  is  incompatible  with  survival.Bones  of  the  cranial  vault  are  absent  but  facial  structures  and  skull  base  are  preserved.  Residual  brain  tissue  is  present  and  floats  free  in  amniotic  fluid.Likely  to  be  the  first  trimester  precursor  to  anencephaly.  Now  called  fetal  acrania–anencephaly  sequence.Incidence  is  3  per  10,000  second  trimester  pregnancies.Sonographic  findings  in  the  first  trimester  include:  absent  calcification  of  the  cranial  bones,  lateral  widening  of  the  cerebral  hemispheres  (the  “Mickey  Mouse”  sign),  and  echogenic  amniotic  fluid.  Second  trimester  findings  include  free-floating  disorganized  brain  tissue  with  preservation  of  the  face.Often  associated  with  omphalocele,  amniotic  band  syndrome,  limb–body  wall  complex,  and  pentalogy  of  Cantrell.Differential  diagnosis  includes  acalvaria,  massive  meningoencephalocele,  amniotic  bands,  limb–body  wall  complex,  hypophosphatasia,  and  osteogenesis  imperfecta  type  II.Condition  is  uniformly  fatal  postnatally.Recurrence  risk  depends  on  underlying  etiology.  If  syndromic  may  have  25%  to  50%  recurrence  risk.  Otherwise,  recurrence  risk  is  2%  to  5%.Preconceptual  folic  acid  (4  mg/day)  is  recommended  for  subsequent  pregnancies.  
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/20
UR  - obgyn.mhmedical.com/content.aspx?aid=1106396403
ER  -