Fabrice Cuillier, MD*; Alice Bertha, MD**; A. Gayon, MD***.

*	Department of Gynecology, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France. Tel: 0262 90 55 22. Fax: 0262 90 77 30;
** ***	Sonologist, Mouffia Street, 97400 Saint- Denis, Ile de la Reunion, France; Department of radiology, Félix Guyon"Hospital, 97400 Saint-Denis, Ile de la Réunion, France.

Case report

The following images show a case of a fetal interhemispheric arachnoid cyst observed at 28 weeks. It was a first pregnancy of a nonconsanguineous couple. The fetus was scanned at 13 weeks and the findings were normal. The triple test was also negative.

At 28 weeks the interhemispheric arachnoid cyst of the fetus was discovered. The lateral cerebral ventricles and corpus callosum were of normal size and morphology. Serological tests (Toxoplasmosis, Rubeola, Parvovirus B19, HIV, CMV, Herpes and Chikungunya) were negative, and so was the Kleihauer test. Amniocentesis was not performed.

MRI confirmed the sonographic findings. The neonate was delivered at term (3200g, boy). Postnatal ultrasonography confirmed the findings, but neurological examination of the neonate was normal. His laboratory tests showed a normal coagulation and no signs of an infection.