Differential diagnosis of brain lesions: Posterior Fossa and Cerebellopontine angle cistern. The three most common lesions are: Vestibular Schwannoma; Meningioma; and, Epidermoid Inclusion Cyst. This short tutorial demonstrates the distinguishing features of these three lesions. MedPix® Teaching Files - http://rad.usuhs.edu/medpix/parent.ph... MedPix® is a Registered Trademark of USUHS.