Endoscopic endonasal versus transcranial approach to resection of olfactory groove meningiomas: a systematic review.

Despite the increasing utility of the endoscopic endonasal approach (EEA) for management of anterior skull base (ASB) pathologies, the optimal treatment strategy for olfactory groove meningiomas (OGM) remains unclear. This project sought to systematically compare outcomes of EEA management with conventional transcranial approach (TCA) for the treatment of OGMs. A systematic review was performed to identify studies that compared outcomes following EEA and TCA for OGMs. Data extracted from each study included gross total resection (GTR), incidence of cerebrospinal fluid (CSF) leaks, and post-operative complications including anosmia. The results of the search yielded 5 studies which met the criteria for inclusion and analysis. All studies compared TCA (n = 922) with EEA (n = 141) outcomes for OGMs. Overall, the rate of gross total resection (GTR) was lower among the endoscopic group (70.9%) relative to the transcranial group (91.5%). The rate of post-operative CSF leak was 6.3% vs. 25.5% for the transcranial and endoscopic groups, respectively. Post-operative anosmia was higher for patients undergoing EEA (95.9%) compared with patients in the transcranial group (37.4%). In this analysis, EEA was associated with a lower rate of GTR and higher incidences of CSF leaks and post-operative anosmia. However, with increasing surgeon familiarity of the endoscopic anatomy and technique for managing ASB pathologies, a nuanced approach may be used to minimize patient morbidity and widen the spectrum of skull base surgery.

An enigmatic clinical entity: A new case of olfactory schwannoma.

Olfactory schwannomas, also described as subfrontal or olfactory groove schwannomas, are very rare tumors, whose pathogenesis is still largely debated. We report a case of olfactory schwannoma in a 39-year-old woman who presented with anosmia and headache. The clinical examination did not show lesions in the nose-frontal region and there was no history of neurofibromatosis. Head MRI and CT scan revealed a lobulated extra-axial mass localized in the right anterior cranial fossa that elevated the ipsilateral frontal pole. Bilateral frontal craniotomy demonstrated a tumor strictly attached to the right portion of the cribriform plate that surrounded the right olfactory tract, not clearly identifiable. The immunohistochemical analysis suggested the diagnosis of typical schwannoma. The patient was discharged without any neurological deficit and a four-month postoperative MRI scan of the brain showed no residual or recurrent tumor.

Olfactory schwannoma: a report of two cases and literature review.

Intracranial schwannoma is a kind of benign intracranial tumors, derived from neuron myelin sheath, growing slowly and curable. Olfactory schwannoma is an exceedingly rare kind of schwannoma, whose origin is still uncovered. Although several theories have been put up for pathogenesis of olfactory schwannoma, till now, none of these hypotheses has been widely accepted and acknowledged officially. Up to date, only 46 cases of olfactory schwannoma were reported across numerous institutes worldwide. Here we gathered two cases from Department of Neurosurgery in Beijing Tiantan Hospital across two years collection.

Olfactory colloid cyst: case report and review of extraventricular colloid cyst literature.

OBJECTIVE: A rare case of an extraventricular colloid cyst located in the olfactory groove extending downward into the ethmoid sinus is presented. This is the second reported case in the world literature. METHODS: A 56-year-old-woman presented with a lesion that was causing hyposmia and cerebrospinal fluid rhinorrhea. The lesion was an extraventricular colloid cyst displacing the left olfactory nerve downward and eroding into the left ethmoid sinus. RESULTS: The lesion was excised, and the anterior skull base was reconstructed successfully via a unilateral subfrontal approach. CONCLUSIONS: There were no complications, and the patient made a full recovery, with resolution of the cerebrospinal fluid rhinorrhea.

[Olfactory ensheathing cell tumour: case report and literature review]. / Tumor de las células envolventes del olfatorio: caso clínico y revisión de la literatura.

Olfactory ensheathing cells are glial cells located in the olfactory bulb and nerve. Microscopically, both olfactory ensheathing cells and Schwann cells have similar morphological and immunohistochemical features. However, olfactory ensheathing cells are negative for Leu-7(CD-57), whereas Schwann cells are positive. We present the case of a 49 year-old male with a history of visual impairment and hyposmia. Radiological CT and MRI studies showed a subfrontal cystic extra-axial mass, which eroded the right cribriform plate, with heterogeneous contrast enhancement. Total excision of the tumour was performed by bifrontal craniotomy. Histological examination initially suggested a schwannoma, with immunohistochemical staining being positive for S-100 protein and negative for epithelial membrane antigen (EMA). However, the tumour was negative for Leu-7. Accordingly, the final diagnosis was olfactory ensheathing cell tumour. Herein, we describe the sixth case of intracranial olfactory ensheathing cell tumour and stress the important role of immunohistochemical techniques in obtaining a definitive diagnosis.

Solitary olfactory groove schwannoma.

Intracranial schwannomas that do not involve major cranial nerves in the posterior fossa are uncommon, especially if they are not associated with neurofibromatosis type II (NF-2). Subfrontal olfactory groove schwannomas are extremely rare. We report a cystic schwannoma arising from the olfactory groove in a 38-year-old Caucasian male who presented with headache, vomiting and visual impairment. We briefly review the pertinent literature, stress the distinctive clinical and neuroradiological findings and discuss the surgical planning and theories about the pathogenesis of schwannomas in this unusual location.

Olfactory schwannoma.

We report a case of olfactory schwannoma with calcification. Intraoperative findings indicated that the tumour originated from the olfactory groove. Intraoperative findings of previous studies have not indicated a clear relationship between subfrontal schwannoma and the olfactory nerve, which seems strange, given the association between tumours and cranial nerves at other sites. We suggest this observation has not been reported because the growing olfactory schwannoma changes the local morphology, affecting the appearance of the olfactory nerve.

[Olfactory groove schwannoma: case report]. / Schwannoma da goteira olfatória: relato de caso.

Intracranial schwannoma not related to cranial nerves are unusual and rarely found in the subfrontal region. We report a case of olfactory groove schwannoma in a 27-year-old male, who presented with anosmia and headache initiated one year ago. At admission, bilateral papilledema was noted with absense of motor deficits or cranial nerves abnormalities. Cranial computed tomography (CT) revealed a bifrontal multicystic isodense enhancing mass lesion causing a frontal ventricular horn compression. Radiological features resembled that of a cystic olfactory groove meningioma. Decompressive bifrontal craniotomy was done. One month later, CT demonstrated a homogeneously contrast-enhancing mass in the olfactory groove region who extended into the left nasal cavity. Magnetic resonance imaging did not add more informations. A second surgical procedure was done through a nasoethmoidal approach with incomplete resection of the lesion. The complete tumor resection was only possible in a third surgery through another bifrontal approach. The hystopathological diagnosis of schwannoma was performed by conventional methods and confirmed by immunohistoquemical staining for S-100 protein. The rarity of this tumor and his clinical, radiological and histological aspects justify this publication.

Olfactory neuroepithelioma arising from the olfactory placode.

The patient was a 54-year-old man, who had lost his sense of smell 6 years previously and had started to become forgetful about 6 months prior to presenting at hospital. MRI admission showed a large multicystic tumor with Gd-DTPA enhancement extending from the anterior cranial fossa through the sphenoid sinus and into the nasal cavity. Histopathological examination revealed extensive proliferation of small round cells that were divided by connective tissue septae. The tumor cells occasionally formed tubular structures, although no basement membranes were present. On immunostaining, round tumor cells were positive for neuron-specific enolase, synaptophysin, and chromogranin A, while cells forming tubules were positive for AE 1 and CAM 5.2. Almost all of the tumor cells were positive for Ber-EP4, and some of the epithelioid cells surrounding the tubular structures were also positive for luteinizing hormone-releasing hormone (LH-RH). Electron microscopy demonstrated sporadic intercellular junctions, many microtubules in the tumor cell processes, and clear- and dense-cored vesicles in the cytoplasm. Based on the results, this case appears to be the first documented neuroepithelioma with Ber-EP4- and LH-RH-positive cells arising from the olfactory placode.

A mobile high-field magnetic resonance system for neurosurgery.

OBJECT: The authors' goal was to place a mobile, 1.5-tesla magnetic resonance (MR) imaging system into a neurosurgical operating room without adversely affecting established neurosurgical management. The system would help to plan accurate surgical corridors, confirm the accomplishment of operative objectives, and detect acute complications such as hemorrhage or ischemia. METHODS: The authors used an actively shielded 1.5-tesla magnet, together with 15 mtesla/m gradients, MR console computers, gradient amplifiers, a titanium, hydraulic-controlled operating table, and a radiofrequency coil that can be disassembled. The magnet is moved to and from the surgical field by using overhead crane technology. To date, the system has provided unfettered access in 46 neurosurgical patients. In all patients, high-definition T1- and/or T2-weighted images were rapidly and reproducibly acquired at various stages of the surgical procedures. Eleven patients underwent craniotomy that was optimized after preincision imaging. In four patients who harbored subtotally resected tumor, intraoperative MR imaging aided the surgeon in removing the remaining tumor. Interestingly, the intraoperative administration of gadolinium demonstrated a dynamic expansion of enhancement beyond the preoperative contrast contour in patients with malignant glioma. These zones of new enhancement proved, on examination of biopsy samples, to be tumor. CONCLUSIONS: The authors have demonstrated that high-quality MR images can be obtained in the operating room within reasonable time constraints. Procedures can be conducted without compromising or altering traditional neurosurgical, nursing, or anesthetic techniques. It is feasible that within the next decade intraoperative MR imaging may become the standard of care in neurosurgery.