Presentation
Incidental finding discovered on CT exam done for head trauma.
Patient Data
Age: 4 years
Gender: Male
From the case:
Compressive arachnoid cyst - middle cranial fossa
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Large extra-axial cystic lesion of left middle cerebral fossa, extending to the insular region measuring 76 x 66 x 50 mm. It elicits an isosignal to the CSF signal on all sequences with no restricted diffusion. It compresses the temporal and frontal lobes as well as the midbrain with a mass effect on the midline structures and thinning of the inner table of the skull.
Case Discussion
MRI features of a large arachnoid cyst of the middle cranial fossa extending to the insular region, type III according to Galassi classification.