Clinical History
A 3 year-old baby girl was referred with motor mental retardation and seizures (infantile spasms) since the age of six month old. Ophthalmologic examination revealed no sense of light in the right eye, right sided retinal colobomatous cyst associated with bilateral microphthalmia, chorioretinal lacuna formations.
Imaging Findings
A 3 year-old baby girl was referred with motor mental retardation and
seizures (infantile spasms) since the age of six months. Ophthalmologic examination revealed no sense of light in the right eye, right sided retinal colobomatous cyst, bilateral microphthalmia, and chorioretinal lacuna formations. MRI study of the patient was performed on a 1.5 T MR scanner, with spin-echo T1, fast spin-echo T2,and FLAIR sequences on three planes. MRI pictures revealed the presence of genu with hypogenesis of the rest of corpus callosum, and partial presence of cingulate gyrus just next to the genu. There was a large bilobulated midline cystic mass with CSF intensity which lodged within the third ventricle, compressing superior vermis inferiorly, and a left sided colpocephaly. Diffuse dysplasia (representing unlayered polymicrogyria) overlying all over the hemispheric surfaces, bands of heterotopic gray matter, and bilateral microphthalmia associated with right sided posterior retinal colobomatous cyst were the additional findings on MRI.
Discussion
Aicardi syndrome is an X-linked dominant disorder, which is characterized by the diagnostic tetrad of infantile spasms, chorioretinal lacunae, mental retardation, and agenesis or hypogenesis of the corpus callosum. The syndrome is seen almost exclusively in females, since early embryonic lethality is observed in males. The mutation forms a balanced translocation of the X chromosome. The patients with Aicardi syndrome present with early-onset infantile spasms, severe mental retardation, severe limitation of motor development and language, and a prognosis of survival for only a few months or years. Aicardi syndrome should be considered as a syndrome in which the clinical findings and prognosis are heterogeneous. Intracranial anomalies include callosal agenesis or hypogenesis, which is typically associated with interhemispheric cysts, absence of the septum pellucidum, agenesis of the anterior commissure, abnormal orientation of the hippocampal formation, gray matter heterotopia, cortical dysplasia, pachygyria, colpocephaly, posterior fossa cysts, cerebellar hemispheric and vermian hypoplasia, choroid plexus papillomas and cysts, optic nerve and chiasmal hypoplasia, and microphthalmia. The type of cortical dysplasia in Aicardi syndrome differs from the classical four-layered microgyria. Neuropathological examination of the brain shows unlayered polymicrogyria that differs from the classical four-layered polymicrogyria, and is similar to cortical anomaly encountered in the so called "cobblestone" lissencephaly. The study of the polymicrogyric cortex with the Golgi method reveals an abnormal orientation of neuronal dendritic tree in the superficial area along the fused molecular layers. Myelination may be delayed in the patients. Ophthalmologic examination reveals characteristic chorioretinal lacunae, which result from retinal dysplasia, anomalous retinal vessels, posterior scleral ectasia, a peripheral fibrous ridge and retrobulbar ocular colobomata. Costovertebral malformations such as hemivertebrae, scoliosis, and absent or malformed ribs may also be associated with Aicardi syndrome.
Differential Diagnosis List
