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.

meningioma:plain ct features

Meningiomas are dural based, benign, slow growing tumors.  They are usually solitary lesions and are 8 times more likely to occur in the brain than the spinal cord.  When in the spinal cord, the thoracic spine is affected 80% of the time. On pathology, meningiomas are usually firm, round and well demarcated.  Meningiomas have a peak incidence in the 5th and 6th decades of life. Presenting symptoms are usually due to mass effect the tumor has on adjacent neural tissue and can include pain, motor or sensory deficits. 
Meningiomas are usually WHO grade I tumors (95%) and treated with surgical excision.   In this case, the patient presented with back pain. She subsequently underwent resection of her tumor without recurrence.
Radiologic overview:
Meningiomas are well circumscribed, strongly enhancing Meningiomas are dural based, benign, slow growing tumors.  They are usually solitary lesions and are 8 times more likely to occur in the brain than the spinal cord.  When in the spinal cord, the thoracic spine is affected 80% of the time. On pathology, meningiomas are usually firm, round and well demarcated.  Meningiomas have a peak incidence in the 5th and 6th decades of life. Presenting symptoms are usually due to mass effect the tumor has on adjacent neural tissue and can include pain, motor or sensory deficits. 

Meningiomas are usually WHO grade I tumors (95%) and treated with surgical excision.   In this case, the patient presented with back pain. She subsequently underwent resection of her tumor without recurrence. 

Radiologic overview:
Meningiomas are well circumscribed, strongly enhancing lesions.  On non-enhanced CT, meningiomas are difficult to recognize and usually isodense to mildly hyper dense when compared to surrounding brain parenchyma.  With contrast, meningiomas enhance homogeneously.  On T1 and T2 weighted images, meningiomas are Iso intense in relation to the spinal cord.  Some meningiomas are well vascularized and may demonstrate flow voids on T2 images.  Meningiomas have well defined borders and do not invade adjacent neural tissue. 

In this case, there is a solitary, intradural, extramedullary, homogeneously enhancing lesion in the mid-thoracic spinal cord.  In an older female patient, meningioma is the likely diagnosis.  Other intradural, extramedullary lesions include schwannoma, drop metastases, epidermoid, arachnoid cyst, and paraganglioma. 
Schwannomas are nerve sheath tumors and have imaging characteristics similar to meningiomas.  They usually occur in younger patients and can have a dumbbell shape as the tumor encases the nerve root across the neural foramen. In drop metastases, multiple contrast enhancing lesions are seen in the cord. Arachnoid cysts can cause mass effect similar to meningiomas, but are fluid filled structures that demonstrate no contrast enhancement. Epidermoid cysts are lobulated structures that minimally enhance and rarely occur in the spine. Paragangliomas rarely occur in the spine and occur in the cauda equina when they do.
Key points:

• Meningiomas are intradural, extramedullary, well circumscribed, homogeneously enhancing lesions.
• Meningiomas are slow growing tumors that compress but do not invade the adjacent neural tissue.
• Presenting symptoms are nonspecific and related to the mass effect caused by the meningioma.
• Other intradural, extramedullary lesions include schwannomas, arachnoid cysts, epidermoid cysts, and drop metastases.