Central Nervous System Lipomas

Intracranial lipomas are not true tumors, but rather congenital malformations. They are uncommon lesions that tend to involve midline structures, such as the case shown here, which is a lipoma of the tuber cinereum.

80% of central nervous system lipomas are supratentorial, with up to 50% of these occurring at the interhemispheric fissure, 20% suprasellar, and 15% in the pineal region. The 20% that are infratentorial involve the cerebellopontine angle, jugular foramen, and foramen magnum.

On CT, they demonstrate fat attenuation, may have calcifications, and do not enhance. They're hyperintense on T1-weighted (A) images and drop out on fat suppressed images (D). On standard spin echo T2 images, they're hypointense with chemical shift artifact. On fast spin echo T2 images, they are iso- to hyperintense (B) and intermediate signal on proton density images. These lesions do not enhance.

References

Saleem SN, Said AH, Lee DH. Lesions of the hypothalamus: MR imaging diagnostic features. Radiographics. 2007 Jul-Aug;27(4):1087-108.