Aneurysm of the Posterior Inferior Cerebellar Artery Filling the Fourth Ventricle

Gliomas in the Region of the Brain Stem

“…Otherwise a benign lesion may be overlooked that could readily have been removed and the patient cured. 1,2,4,9,18,''~ Differential diagnosis includes, of course, consideration of the more common posterior fossa tumors 1~ such as medulloblastomas and ependymomas of the fourth ventricle, and astrocytomas and hemangioblastomas ~ of the cerebellum that have encroached upon the fourth ventricle or brain stem. Metastatic malignant tumors, chordomas, 23 luetic pachymeningitis, abscess, aneurysm, -~ demyelinating diseases, and infarctions TM must also be differentiated, as well as histologically benign extra-axial tumors such as cerebellopontine neurinomas or meningiomas.…”

21 Endovascular Treatment of Posterior Circulation Aneurysms

“…In patients presenting with a ruptured aneurysm the concomitant presence of acute subarachnoidal hemorrhage with the associated cerebral edema and adhesion of aneurysm to the surrounding thrombus may increase the difficulty of safely accessing PICA aneurysms with open microsurgical technique, especially if located near deep brain stem structures with interposed cranial nerves and perforator arteries. Aneurysm of the distal PICA may also present with fourth-ventricular hemorrhage (Urbach et al 1995), mass (Alexander et al 1966;Yamaura et al 1980), or intraparenchymal hematoma that may be mistaken for spontaneous cerebellar hemorrhage.…”