corpus callosal lipoma- case report

a 39 yr old male presenting with vague headache for a month was advised MRI brain
findings: lipoma involving splenium with partial agenesis.

Corpus callosal lipoma

Lipomas of corpus callosum

Lipomas of corpus callosum are morphologically 

classified into two groups: anterior lipomas are 

indicated as tubulonodular, usually bigger than 2 cm 

and frequently associated with hypogenesis/agenesis 

of corpus callosum, frontal lobes anomalies, frontal 

encephalocele, calcifications, and/or ocular anomalies. 

Posterior lipomas are indicated as curvilinear, they are 

thin and usually lay on splenium; they are less frequently 

associated with corpus callosum anomalies and/ or other 

encephalic anomalies.

Association with hypogenesis/agenesis of corpus callosum 

is frequent, being present in 90% of anterior lipomas and 

in 30% of posterior lipomas.

A pure (isolated) lesion of corpus callosum probably 

does not cause symptoms. 

Clinical manifestations like seizures and mental disorders must be attributed 

to concomiting nervous tissue anomalies. Epilepsy 

is one of the most frequent symptom: when present it 

appears before the age of 15, is often partial and severe.

Lipomas of corpus callosum can also cause 

obstructive hydrocephalus.

In hypogenesis/agenesis of corpus callosum, nervous 

fibers that do not cross the interemispheric fissure, run 

parallel to it, along the medial walls of both lateral 

ventricles (Probst’s bundles), deforming the III ventricle 

and the lateral ventricles.

It is not yet clearly explained the eventual mechanism 

that could deform the posterior segments of ventricular 

cavities. It was hypothesized that posterior fibers that don’t 

cross midline, could interfere with correct development 

of parietal and occipital white matter, being associated 

with hypogenesis of hippocampus.

Diagnosis accidentally occurs during diagnostic 

procedures in case of an encephalic disorder.Sonographic 

prenatal diagnosis is possibile at 26 weeks of gestation.

On CT scans, lipomas appear as areas of hypodensity, 

that can contain calcific hyperdensities, so, these 

aspecific aspects, prospect differential diagnosis with 

dermoid cysts and teratomas. MRI scans 

do not leave doubts, infact fat signal is characteristically 

hyper in T1w and T2w sequences, and in FATSAT 

sequences it is suppressed. Angiography shows 

displastic cerebral arteries involved in the lesion, but not 

compressed or displaced.

There’s no indication to surgical treatment in isolated 

(pure) corpus callosum lesions; on the other hand, 

surgical outcomes are controversial because is difficult 

a complete debulking that spare the nervovascular 

structures involved.

Prognosis and symptoms depends on associated 

malformations. Risks to be considered, above all in 

the evolutive age, are hydrocephalus and epilepsy.