Interhemispheric multiloculated ependymal cyst with dysgenesis of the corpus callosum: a case in a preterm fetus.

INTRODUCTION: The authors report a case of interhemispheric ependymal cyst accompanied with agenesis of the corpus callosum in a fetus. DISCUSSION: Routine ultrasound and subsequent magnetic resonance imaging of a 20-year-old woman at 33 weeks and 1 day of gestation detected a large interhemispheric cystic lesion in the fetal cranial cavity. Caesarian section was carried out at 36 weeks because of the progressive enlargement of the fetal head. The cyst was multiloculated and a cyst peritoneal shunt placement resulted in collapse of the drained cyst components followed by enlargement of others. After wrack-a-mole-like shunt revisions, open surgery was performed at the age of 2 years. Cyst walls were fenestrated and the cavities were communicated with each other and eventually with the lateral ventricle. Pathological diagnosis of the cyst wall was ependymal cyst. The boy is now 3 years old, and growing without apparent developmental delay or recurrence. Current concept and management policy of the interhemispheric cyst accompanied with agenesis of the corpus callosum is reviewed.