There is a large extra-axial heterogeneous mass that grossly indents the left frontal lobe. The lesion demonstrates heterogeneous T1 and T2 signal with a thin rim of contrast enhancement along its anterior and medial margins, and calcification within its anterior and posterior rim. The bulk of the central lesion suppresses on FLAIR, but demonstrates intermediate diffusion restriction (~900 x 10-6 cm2/s). The peripheral component of the mass demonstrates intermediate T1/T2 signal.
Anterior to the mass are fat signal lobules that may represent ruptured elements. Spectroscopy (not shown) demonstrates elevated lactate peak within parts of the lesion. No elevated CBV/CBF within the lesion. Mass compresses the left lateral ventricle, causing 15 mm of midline shift to the right and uncal herniation with effacement of the third ventricle and obstructive hydrocephalus. Remainder of the brain is unremarkable.
The majority of the mass has imaging appearances of an epidermoid cyst with dystrophic calcification, however the presence of fatty components suggests that this actually represents a dermoid cyst (with sebum) or (less likely) a mature cystic teratoma.