title: Open neural tube defects: immunocytochemical demonstration of neuroepithelial cells in amniotic fluid.
abstract: Cytologic evaluation of second trimester amniotic fluid (AF) is a rapid, inexpensive adjunct to prenatal diagnosis of open neural tube defects (ONTDs). Our goal was to determine whether the neural-appearing cells and/or large foamy macrophages in the AF of anencephalics are indeed of neural and/or glial origin. In two second trimester patients with elevated serum alpha-fetoprotein (AFP) and polyhydramnios, fetal sonogram studies showed anencephaly; amniocentesis was performed for AF-AFP, cytogenetic, and cytologic studies. AF sediment smears were initially Papanicolaou-stained; next, the same smears were immunoperoxidase (IP)-stained for glial fibrillary acidic protein (GFAP). If GFAP negative, slides were restained for synaptophysin (SYN) and neuron-specific enolase (NSE). Both AFs contained small neural-appearing cells (5-10 microns) singly and in clusters, with dense, round, homogeneous nuclei, an occasional nucleolus, and scant cytoplasmic rim. These were GFAP negative and SYN and NSE positive; the large vacuolated, lipid-laden macrophages (20-40 microns) were negative for all three IP stains. In conclusion, positive IP staining for SYN and NSE supports the morphologic impression that small dark cells in AF are of neural origin, while negative IP staining of large foamy macrophages suggests nonneural, nonglial origin.
authors.affiliation: Department of Surgical Pathology, College of Physicians and Surgeons, New York, NY 10032, USA.
authors.forename: E
authors.initials: E
authors.lastname: Greenebaum
authors.forename: M M
authors.initials: MM
authors.lastname: Mansukhani
authors.forename: D S
authors.initials: DS
authors.lastname: Heller
authors.forename: I
authors.initials: I
authors.lastname: Timor-Tristsch
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry / Q000166:cytology*; D004848:Epithelium / Q000737:chemistry / Q000473:pathology; D005260:Female; D005315:Fetal Diseases / Q000473:pathology*; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D009420:Nervous System / Q000737:chemistry / Q000473:pathology*; D009436:Neural Tube Defects / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D016708:Synaptophysin / Q000032:analysis
chemical_list: D005904:Glial Fibrillary Acidic Protein; D016708:Synaptophysin; D010751:Phosphopyruvate Hydratase