Learning objectives
To show the pathognomonic imaging findings for intracranial lipomas,
using both computed tomography (CT) and magnetic resonance imaging (MRI).
To differentiate lipomas from other intracranial pathologies.
To show the importance of preoperative imaging in cases,
where surgery treatment is indicated.
Background
Intracranial lipomas are rare lesions (0.06-0.46% of all intracranial tumors) and can be located anywhere in the intracranial compartment,
although they have a predilection to develop near the midline of falx cerebri over the corpus callosum.
Other reported cases with different locations include cerebellopontine angle (CPA),
the quadrigeminal cerebellar cistern,
the choroid plexus of the ventricles,
cerebellum,
insula,
chiasmatic cistern,
etc.
In some cases there might be intra and extracranial components,
connected to each other by fibrous-lipomatous stalk.
There are many theories of the pathogenesis...
Findings and procedure details
Often intracranial lipoma is an incidental finding on a head CT performed for another indication.
In some cases,
additional MRI is performed to verify the detected mass.
In both modalities most commonly they are reported as well-delineated,
oval or lobulated extra-axial fatty mass.
On CT,
lipomas appear as hypodense lesions (-50UH and -100UH) with no surrounding edema and no enhancement in the postcontrast series.
If there are any calcifications,
they are located peripherally within the surrounding fibrous capsule.
The MRI findings include lesions with fat-intensity...
Conclusion
Although lipomas are rare,
usually benign lesions,
they have a very pathognomonic appearance on CT and especially MR imaging and should be not mistaken with other tumor formations.
References
Truwit CL,
Barkovich AJ (1990) Pathogenesis of intracranial lipoma: an MR study in 42 patients.
AJR Am J Roentgenol 155:855–864
Yildiz H,
Hakyemez B,
Koroglu M,
Yesildag A,
Baykal B.
Intracranial lipomas: importance of localization.
Neuroradiology.
2006;48(1):1-7.
Ahmetoglu A,
Kul S,
Kuzeyli K,
Ozturk MH,
Sari A.
Intracranial and subcutaneous lipoma associated with sagittal sinus fenestration and falcine sinus.
AJNR American journal of neuroradiology.
2007;28(6):1034-5.
Jabot G,
Stoquart-Elsankari S,
Saliou G,
Toussaint P,
Deramond H,
Lehmann P.
Intracranial lipomas: clinical appearances on neuroimaging and clinical...