congenital malformations of brain 2

6
Intracranial lipoma Intracranial lipomas are not tumours as such, but rather a result of abnormal differentiation of embryologic meninx primitiva . They are frequently associated with abnormal development of adjacent structures.

Upload: battulga-munkhtsetseg

Post on 13-Apr-2017

80 views

Category:

Health & Medicine


0 download

TRANSCRIPT

Page 1: Congenital malformations of brain 2

Intracranial lipoma

Intracranial lipomas are not tumours as such, but rather a result of abnormal differentiation of embryologic meninx primitiva. They are frequently associated with abnormal development of adjacent structures.

Page 2: Congenital malformations of brain 2

LocationIntracranial lipomas are widely distributed in the intracranial compartment and although they can be found essentially anywhere, certain regions are characteristic and are discussed separately.• pericallosal lipoma (45%)

– associated with agenesis of the corpus callosum is ~50% of cases– divided morphologically into tubonodular and curvilinear types

• quadrigeminal cistern lipoma (25%)– associated with underdevelopment of the inferior colliculus

• suprasellar cistern lipoma (15%)• cerebellopontine angle lipoma (10%)

– the facial nerve and vestibulocochlear nerve often courses through the lipoma

• sylvian fissure (5%)

Page 3: Congenital malformations of brain 2

MRI

MRI with and without fat saturation are able to make the diagnosis easily. In the absence of fat saturated images, then chemical shift artefact may be useful. Signal characteristics are not surprisingly that of fat: • T1: high signal intensity• T2: high signal intensity • T1 C+ (Gd): no enhancement• fat saturated sequences: low signal • Often the lipomas are traversed by cranial nerves and

adjacent vessels, best seen on high resolution sequences.

Page 4: Congenital malformations of brain 2

MRI demonstrates a mass in the quadrigeminal plate cistern with very high T1 and T2 signal which demonstrates fat saturation and chemical shift artefact, confirming that the mass is composed of fat, and as such represents a quadrigeminal cistern lipoma.

Page 5: Congenital malformations of brain 2

Well defined fat lesion is again demonstrated on the tentorium cerebelli expressing high T1 and FLAIR signal.

Page 6: Congenital malformations of brain 2

Interhemispheric hyperintense structure on T1-weighted image consistent with a lipoma associated with hypoplasia of the splenium of the corpus callosum (bright fat tissue on T1 sequence). (A) Sagittal plane. (B) Transverse/axial plane.