Fetal lymphangiectasia--another cause for a positive amniotic fluid acetylcholinesterase test.

A case of a fetal lymphangiectasia on the ventral aspect of the neck was detected prenatally by ultrasound examination. Polyhydramnios was present. AFP values in amniotic fluid and maternal serum were in the upper normal range. An acetylcholinesterase band was found on gel electrophoresis. After delivery the prenatal diagnosis of congenital isolated lymphangiectasia was confirmed. The case illustrates a further example of a positive acetylcholinesterase test not associated with a neural tube defect.