A 25-year-old woman (G1P0) with non contributive medical history was referred to our antenatal unit at 24 weeks of pregnancy. Her previous first trimester scan was reported to be normal. Our examination revealed an interhemispheric arachnoid cyst in combination with unilateral cleft lip. Corpus callosum appeared normal and so did the rest of fetal anatomy. Amniocentesis was also done with normal result (46,XY) and amniotic fluid was negative for toxoplasmosis, rubella, cytomegalovirus, and herpes virus infections). Following MRI confirmed the finding of interhemispheric arachnoid cyst.

During the third trimester the arachnoid cyst had disappeared. The baby was born in term (XY, 3000 g) and his postnatal ultrasound did not found the arachnoid cyst any more. The cleft lip was corrected surgically. 

By our opinion the combination of fetal cleft lip with arachnoid cyst represents just a random association and does not constitute a syndromic relation.

Images 1, 2, 3: 24 weeks; images show transverse (Images 1, 2) and sagittal (Image 3) scans of the fetal head with interhemispheric arachnoid cyst.

 



Images 4, 5, 6: 24 weeks; images show normal cavum septum pellucidum and corpus callosum.

  



Images 7, 8, 9, 10: 24 weeks; images show 2D (Images 7, 8, 9) and 3D (Image 10) scans of the fetal cleft lip.

 

 

Images 11, 12, 13, 14: MRI images showing fetal interhemispheric arachnoid cyst.