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

Affiliations
  • 1Department of Obstetrics and Gynecology, Eulji University Medical Center, Eulji University College of Medicine, Daejeon, Korea. rho27kim@eulji.ac.kr
  • 2Department of Neurosurgery, Eulji University Medical Center, Eulji University College of Medicine, Daejeon, Korea.

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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