Fat in Sulci/Cisterns/Ventricles
Yoshimi Anzai, MD, MPH
Judy Tan, MD
DIFFERENTIAL DIAGNOSIS
Common
Lipoma
Subacute Hemorrhage (Mimic)
Less Common
Dermoid Cyst (Ruptured)
Teratoma
Rare but Important
Lipoidal Contrast (Mimic)
Metaplastic Meningioma (Lipomatous)
Choroid Plexus Xanthogranuloma (Mimic)
Encephalocraniocutaneous Lipomatosis
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Review brain CT; fat may have confusing MR signal intensity
MR fat suppression technique helps differentiate lesions
Helpful Clues for Common Diagnoses
Lipoma
Well-defined nonenhancing fatty mass
Locations: Interhemispheric/pericallosal, suprasellar, quadrigeminal, & cerebellopontine angle (CPA)
Bulky interhemispheric/pericallosal lipomas often associated with agenesis/dysgenesis of corpus callosum
Subacute Hemorrhage (Mimic)
T1 shortening in subacute blood may mimic fat
Blood products show “blooming” artifact on GRE sequence
Does not suppress with fat suppression
Helpful Clues for Less Common Diagnoses
Dermoid Cyst (Ruptured)
Fat droplets in sulci
Signal nulled with fat suppression
Teratoma
Midline mass containing Ca++, soft tissue, cysts, & fat
Soft tissue component enhances
Pineal region common; suprasellar less common
Helpful Clues for Rare Diagnoses
Lipoidal Contrast (Mimic)
Oil-based contrast agent
High T1 signal intensity
Metaplastic Meningioma (Lipomatous)
Dural-based enhancing mass with fat density/signal intensity
Look for adjacent hyperostosis
Choroid Plexus Xanthogranuloma (Mimic)
Nonneoplastic, noninflammatory cysts of choroid plexus
Low density on CT may mimic fat
Encephalocraniocutaneous Lipomatosis
Scalp lipomas ipsilateral to brain anomalies
CPA, Meckel cave, & foramen magnum lipomas
Image Gallery
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