Endodermal Cyst of the Posterior Fossa

We report a case of endodermal cyst of the posterior fossa. A 44-year-old man presented with headache for three months. Computed tomography and magnetic resonance imaging revealed a 6x2.5x2cm sized extra-axial non-enhancing cystic lesion on the ventral aspect to brain stem. To avoid retraction injury to brain stem, far lateral transcondylar approach was selected. Right suboccipital craniotomy and partial removal of occipital condyle with resection of C-1 and C-2 hemilaminae exposed the extra-axial cyst well. The cyst has a whitish thick membrane. It was not adherent to brain stem and lower cranial nerves. Total removal of the cyst was done without difficulty. Histological analysis disclosed a layer of pseudostratified columnar epithelium with basement membrane. The result of immunohistochemical study was consistent with endodermal cyst.

A Case of Large Foramen Magnum Schwannoma

Most intracranial schwannomas originate from the cranial nerve especially CN V, VIII. However, schwannomas from low-cranial nerve are rarely reported. We report a case of large foramen magnum schwannoma in a 26 year-old-man presenting swallowing difficulty, nausea and vomiting. Magnetic resonance image revealed a cystic multilobulated huge mass from midclivus to atlas which compressed brain stem. The mass was removed by far-lateral transcondylar approach and confirmed with schwannoma which originated from hypoglossal nerve.

Far Lateral Approaches for Intracranial Aneurysms / 대한뇌혈관학회지

Surgical approaches to the posterior circulation aneurysms are difficult and still remained as a matter of debate. Many skull base approaches has been developed to overcome the inadequate exposure of these aneurysm by conventional surgical approaches. Far lateral approaches are an extension of suboccipital approach to expose neurovascular structures around the lower clivus. Aneurysms locating at the vertebral arteries, vertebrobasilar junction and lower basilar artery could be exposed by these approach. However, it is not still evident which kind of far lateral approach is most appropriate for the aneurysms of various locations at these vascular territory. Among the 3 kinds of far lateral approaches, such as far lateral, far lateral transcondylar and extreme lateral transcondylar approach, far lateral approach is not recently used frequently. Far lateral transcondylar approach is good far the aneurysm at the origin of posterior inferior cerebellar artery and the extreme lateral transcondylar approach is useful to expose aneurysms around vertebrobasilar junction. For an appropriate selection of surgical approaches, useful surgical guidelines are mandatory. The recent use of "intermeatal line" and "K lines" and others are of many help for the lower basilar and vertebral artery aneurysms. Surgical approach itself needs knowledge and experience for an adequate performance. Once exposed appropriately manipulation of aneurysms at these locations are not very complicated. Microsurgical anatomy of each surgical step is essential for the sucessful management of aneurysms locating at the lower clivus.

Intracranial Hypoglossal Neurinoma: A Case Report

Hypoglossal neurinoma is vary rare cranial base neoplasm. With the recent advances in the neuroimaging and surgical technique, radical surgical resection is amenable. A case of hypoglossal neurinoma which is located ventral to the medulla is reported. The patient was presented with right hypoglossal nerve palsy, glossal hemiatrophy, and decreased gag reflex on the right side. Magnetic resonance imaging(MRI) revealed an ovoid mass ventral to the medulla with enlarged hypoglossal canal. Because of the ventral location of the mass, far lateral transcondylar approach was selected to minimize the postoperative morbidity. Radical total resection was achieved. This report describes that far lateral transcondylar approach is better than conventional suboccipital approach in regards to satisfactory exposure of the hypoglossal canal and prevention of excessive retraction of the neuraxis.