Obstet Gynecol Sci.  2014 May;57(3):223-227. 10.5468/ogs.2014.57.3.223.

A meningomyelocele with normal intracranial signs on ultrasound and false-negative amniotic fluid alpha-fetoprotein and acetylcholinesterase

• Yoon CH
• Kang SK
• Jin CH
• Park MS
• Rho JH

• KMID: 1704429
• DOI: http://doi.org/10.5468/ogs.2014.57.3.223

Abstract

Neural tube defects are the major targets of prenatal diagnoses, along with Down syndrome. Prenatal diagnosis of spina bifida is possible at second trimester of gestation through alpha-fetoprotein and acetylcholinesterase biochemistry assays and ultrasound. In particular, the discovery of characteristic intracranial signs on ultrasound leads to a very high diagnosis rate. However, it is rare for spina bifida to present without intracranial signs while also showing normal values of maternal serum alpha-fetoprotein, amniotic fluid alpha-fetoprotein, and acetylcholinesterase. In our hospital, a fetus with spina bifida was delivered at 37+5 weeks' gestation by cesarean section, and was continually followed up over 2 years to date.

Keyword

Intracranial sign; Meningocele; Meningocele repair; Maternal serum alpha-fetoproteins; Spinal dysraphism

MeSH Terms

Acetylcholinesterase*
alpha-Fetoproteins*
Amniotic Fluid*
Biochemistry
Cesarean Section
Diagnosis
Down Syndrome
Female
Fetus
Humans
Meningocele
Meningomyelocele*
Neural Tube Defects
Pregnancy
Pregnancy Trimester, Second
Prenatal Diagnosis
Reference Values
Spinal Dysraphism
Ultrasonography*
Acetylcholinesterase
alpha-Fetoproteins

Figure

• 

  Fig. 1 (A,B) At 22+6 weeks' gestation, sonography shows normal range of cistern magna, no intracranial signs at axial view. Cystic mass is present in the lumbosacral area. (C) Native-polyacrylamide gel eletrophoresis analysis of amniotic fluid acetylcholinesterase was performed at 22+6 weeks' gestation. 1→ slow migrating thin band with specific acetylcholinesterase inhibitor; a negative control (lane NC). 2→ additional fast moving thick band of specific acetylcholinesterase; a positive control (lane PC). Lane Pt, patient shows a thin negative pattern.

• 

  Fig. 2 (A) Immediate postnatal brain magnetic resonance imaging (MRI) shows normal findings. There is no lemon sign and no ventriculomegaly. (B) Spinal MRI. Sagittal T2-weighted MRI image of the lumbar meningocele. The level of defect was between L3 and L4. (C) The histopathologic examination revealed a meningocele (H&E, ×100). (D) Strong reactivity to epithelial membrane antigen (EMA) was seen in the epithelial lining and granules on the surface of the arachnoid and pia mater (EMA, ×100).

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