The Previous show CPA Cystic mass lesion that follow CSF signal intensity on T1WI and T2WI, and it show higher (dirty) signal than CSF on FLAIR.this is typical for epidermoid , the latter FLAIR dirt signal is what differentiate it from Arachnoid Cyst.
Ependymona doesn’t follow CSF signal on T1WI and T2WI.
GBM is a supratentorial tumor.
Differential Diagnosis:
Shwanoma (Vestibular): Solid Enhancing Tumor
Meningioma: has dural base and doesn’t follow CSF signal.
Arachnoid Cyst: similar to epidermoid but follow CSF signal on FLAIR.
Pearls:
Benign tumor with slow growth due to epithelial lining desquamation.
Path shows solid lesion with keratinaceous debris.
“Black” epidermoid: follows CSF.
Cholesterol in solid crystalline state, keratin within tumor, CSF within tumor interstices.
