Syncope.

Our appreciation is extended to Dr. Jared Bailey, Indiana University Department of Radiology, for contributing this case.

Syncope.

Syncope.

• Lipoma
• Dermoid

Syncope.

Intracranial lipomas are rare representing less than 0.5% of intracranial masses. They originate from persistent maldevelopment of embryonic meninx primitive that would normally differentiate into leptomeninges and cisterns. The are identical to adipose tissue anywhere else in the body. Symptoms at the time of presentation are entirely dependent upon location and mass effect as the lesions themselves do not cause symptoms. 80% are supratentorial with majority originating in the interhemispheric fissure. Another 15-20% occur in the suprasellar region. The 20% that occur in the infratentorial areas can occur in the CPA and extend into the internal auditory canal. They are most commonly found at autopsy and are rarely removed unless symptomatic. They can expand with steroid treatment.

CT: The lesion should be hypo intense with Hounsfield units in the fat range (-50 to-100). There can be calcifications.

MR: T1 hyper intense that becomes hypo intense with fat suppression. T2 hypo intense with chemical shift artifact Hyper intense on FLAIR and does not enhance on post contrast imaging.

Key points:

• Intracranial lipomas are rare, but when they occur the majority are supratentorial.
• They show fat intensity on CT and are hyper intense on T1 that become hypo intense on fat saturation.
• They are often asymptomatic and are usually found on autopsy.

1. Statdx.com 2005-2011.
2. Yildiz H et al: Intracranial lipomas; importance of localization. Neuroradiology. 48(1):1-7. 2006.

Syncope.