Case Of the Week (COW) 23 Mar 2014
Answer:
ALOBAR PROSENCEPHALY.
Findings:
Single monoventricular cavity found occupying the frontal portion of the cerebrum and fused thalami . Single ventricular cavity displaces the rim of cortical mantle which is shaped like a horseshoe or boomerang. Fused thalamus appearing as a bump. Cyclopia with single eye with Supraorbital Probosis.
Discussion:
1.Alobar No cleavage of the forebrain into right and left hemispheres, into diencephalon and telencephalon and into the olfactory and optic bulbs. Single, amorphous ventricle, fused thalami and absence of the corpus callosum, falx cerebri, optic tracts and olfactory bulbs.
2. Semilobar Brain's hemispheres have a slight tendency to separate & demonstrates partial segmentation of the ventricles and incomplete fusion of the thalami .
3.Lobar - evidence of separate brain hemispheres. Severe cases often have a dorsal cyst, thought to result from obstruction to CSF flow by fused thalami.
ALOBAR PROSENCEPHALY: Pancake” or “horseshoe” brain Monoventricle Large dorsal cyst Fused diencephalon Basal ganglia & thalami may form gray matter fusion mass No interhemispheric fissure No olfactory nerves Alobar holoprosencephaly has three variants: pancake,cup, and ball. The pancake type has a small, flattened plate of cerebrum anteriorly, with a large dorsal cyst posteriorly. The cup type has more anterior cerebrum, forming an anterior cuplike mantle and a dorsal cyst. The ball type has a single, featureless, monoventricle surrounded by a mantle of ventricle of varying thickness Semilobar Holoprosencephaly: Partial occipital/temporal horns Moderate sized dorsal cyst Fused diencephalon Partial fusion of basal ganglia > thalami Interhemipheric fissure present posteriorly Absent of hypoplastic olfactory tracts and bulbs Corpus callosum is rudimentary Lobar Holoprosencephaly: Formed lateral ventricles Small or no dorsal cyst Fused diencephalon and/or fornices +/- partial fusion of basal ganglia > thalami Interhemispheric fissure nearly normal Small or normal olfactory nerves.
FACIAL CHANGES ASSOCIATED WITH HOLOPROSENCEPHALY: 1. Cyclopia with single eye, with or without proboscis 2. Ethmocephaly (hypotelorism and proboscis between the eyes) 3. Cebocephaly (hypotelorism, nose with single nostril) 4. Median cleft lip/palate and hypotelorism Alobar holoprosencephaly has been diagnosed as early as 9 weeks through demonstration of a single ventricle, single orbit, and proboscis.
Contributed By:
Prof. N. Kailasanathan Natarajan
Barnard Institute of Radiology
Answer:
ALOBAR PROSENCEPHALY.
Findings:
Single monoventricular cavity found occupying the frontal portion of the cerebrum and fused thalami . Single ventricular cavity displaces the rim of cortical mantle which is shaped like a horseshoe or boomerang. Fused thalamus appearing as a bump. Cyclopia with single eye with Supraorbital Probosis.
Discussion:
1.Alobar No cleavage of the forebrain into right and left hemispheres, into diencephalon and telencephalon and into the olfactory and optic bulbs. Single, amorphous ventricle, fused thalami and absence of the corpus callosum, falx cerebri, optic tracts and olfactory bulbs.
2. Semilobar Brain's hemispheres have a slight tendency to separate & demonstrates partial segmentation of the ventricles and incomplete fusion of the thalami .
3.Lobar - evidence of separate brain hemispheres. Severe cases often have a dorsal cyst, thought to result from obstruction to CSF flow by fused thalami.
ALOBAR PROSENCEPHALY: Pancake” or “horseshoe” brain Monoventricle Large dorsal cyst Fused diencephalon Basal ganglia & thalami may form gray matter fusion mass No interhemispheric fissure No olfactory nerves Alobar holoprosencephaly has three variants: pancake,cup, and ball. The pancake type has a small, flattened plate of cerebrum anteriorly, with a large dorsal cyst posteriorly. The cup type has more anterior cerebrum, forming an anterior cuplike mantle and a dorsal cyst. The ball type has a single, featureless, monoventricle surrounded by a mantle of ventricle of varying thickness Semilobar Holoprosencephaly: Partial occipital/temporal horns Moderate sized dorsal cyst Fused diencephalon Partial fusion of basal ganglia > thalami Interhemipheric fissure present posteriorly Absent of hypoplastic olfactory tracts and bulbs Corpus callosum is rudimentary Lobar Holoprosencephaly: Formed lateral ventricles Small or no dorsal cyst Fused diencephalon and/or fornices +/- partial fusion of basal ganglia > thalami Interhemispheric fissure nearly normal Small or normal olfactory nerves.
FACIAL CHANGES ASSOCIATED WITH HOLOPROSENCEPHALY: 1. Cyclopia with single eye, with or without proboscis 2. Ethmocephaly (hypotelorism and proboscis between the eyes) 3. Cebocephaly (hypotelorism, nose with single nostril) 4. Median cleft lip/palate and hypotelorism Alobar holoprosencephaly has been diagnosed as early as 9 weeks through demonstration of a single ventricle, single orbit, and proboscis.
Contributed By:
Prof. N. Kailasanathan Natarajan
Barnard Institute of Radiology