Maria Peris-Celda

Glioneuronal Heterotopia Presenting as Cerebellopontine Angle Tumor of Cranial Nerve VIII

BACKGROUNDnVestibular schwannomas and meningiomas account for the great majority of lesions arising in the cerebellopontine angle. In this report, we present a case of glioneuronal heterotopia, also known as glioneuronal hamartoma, arising from cranial nerve VIII, which is an extremely uncommon lesion. Important radiologic and surgical aspects are reviewed, which may help in early recognition and intraoperative decision making when these lesions are encountered.nnnCASE DESCRIPTIONnA healthy 29-year-old female presented with intermittent right facial numbness. Magnetic resonance imaging showed an incidental, minimally enhancing cerebellopontine angle lesion on the right cranial nerve VII-VIII complex. The patient declined serial observation and opted for operative intervention for resection. Intraoperatively, the lesion resembled neural tissue and was continuous with the VIII cranial nerve. Pathologic analysis demonstrated mature glioneuronal tissue consistent with hamartomatous brain tissue. The patient maintained normal hearing and facial nerve function after surgery. Radiologic, surgical, and pathologic characteristics are described.nnnCONCLUSIONSnEctopic glioneuronal tissue of cranial nerve VIII is a rare non-neoplastic lesion and should be considered in the differential diagnosis of unusual-appearing intracanalicular and cerebellopontine angle lesions. The congenital and benign nature of this entity makes observation a valid option for these cases, although they are so infrequent that they are often presumptively managed as vestibular schwannomas. Attempts to radically resect these lesions may result in higher rates of hearing loss or facial palsy due to their continuity with cranial nerves.

Trigeminal Nerve Schwannoma of the Cerebellopontine Angle

Introduction u2003Large and even moderate sized, extra-axial cerebellopontine angle (CPA) tumors may fill this restricted space and distort the regional anatomy. It may be difficult to determine even with high resolution magnetic resonance imaging (MRI) if the tumor is dural-based, or what the nerve of origin is if a schwannoma. While clinical history and exam are helpful, they are not unequivocal, particularly since many patients present with a myriad of symptoms, or conversely an incidental finding. We present an atypical appearing, asymptomatic CPA tumor, ultimately identified at surgery to be a trigeminal schwannoma. Case History u2003A 40-year-old man presented with new-onset seizure. MRI identified an incidental heterogeneously contrast-enhancing CPA lesion ( Fig. 1A – D ). The tumor was centered on the internal auditory canal (IAC) with no tumor extension into Meckels cave, IAC or jugular foramen. Audiometry demonstrated 10db of relative left-sided hearing loss with 100% word recognition. Physical examination was negative for focal neurologic deficits. A retrosigmoid craniotomy was performed and an extra-axial, yellow-hued mass was encountered and resected, which was ultimately confirmed to originate from the trigeminal nerve ( Video 1 ). Gross total resection was achieved, and the patient recovered from surgery with partial ipsilateral trigeminal sensory loss and no other new neurologic deficits. Conclusion u2003Pure CPA trigeminal schwannomas are rare, but should be considered in the differential for enhancing CPA lesions. Although, Meckels cave involvement is frequently observed, it is not universal, and pure CPA schwannomas of all cranial nerves IV–XII have been reported in the literature. The link to the video can be found at: https://youtu.be/AlodYCu70F8 .

Extrapolating the Limits of the Nasoseptal Flap With Pedicle Dissection to the Internal Maxillary Artery

BACKGROUNDnThe nasoseptal flap is the main pedicled flap used for endoscopic cranial base reconstruction. For large anterior cranial base defects, the anterior edge is a concern for the nasoseptal flap reach.nnnOBJECTIVEnTo present a surgical technique that completely releases the vascular pedicle of the nasoseptal flap from the sphenopalatine artery (SPA) foramen improving considerably the reach of the flap.nnnMETHODSnA patient with left anterior cranial base fracture involving the posterior table of the frontal sinus, who presented with cerebrospinal fluid leak and contused brain herniation to the ethmoid and frontal sinuses. Unilateral endoscopic endonasal anterior cranial base reconstruction was performed with left sided nasoseptal flap. The nasoseptal flap pedicle was dissected and completely released from the SPA foramen. The flap was left attached only to the internal maxillary artery (IMAX) vascular bundle.nnnRESULTSnThe flap covered the entire left anterior cranial base, from the planum sphenoidale to the posterior table of the frontal sinus. There was complete obliteration of the cerebrospinal fluid fistula postoperatively with resolution of the radiographic pneumocephalus and the patients rhinorrhea.nnnCONCLUSIONnThe complete release of the nasoseptal flap pedicle from the SPA foramen is feasible and remarkably improves the reach of the flap. It also increases the reconstructive area of the flap since the entire septal mucosa can be used for reconstruction and the pedicle length is based exclusively upon the SPA/IMAX.

Endoscopic Endonasal Resection of Orbital Apex Cavernous Hemangioma: 2-Dimensional Operative Video

A 52-yr-old woman was referred to a tertiary medical center for evaluation of 2 yr of progressive visual symptoms and 1 yr of retro-orbital pressure. Her ophthalmologic exam was unrevealing except for mild asymmetrical impairment in color perception. A gadolinium contrast-enhanced magnetic resonance image of the head showed a left extraconal orbital apex lesion consistent with cavernous hemangioma. Computed tomography reveled bony remodeling of the medial-inferior orbital walls with superior orbital fissure expansion. The lesion was endoscopically resected and confirmed by pathological analysis. The endoscopic approach is demonstrated in detail, including correlation with cadaveric anatomic specimens‡. During the approach, a rescue nasoseptal flap was raised in case the orbit required further support after tumor resection, but was replaced as this was not needed. This patient had a brief period of postoperative diplopia, which resolved 1 wk after surgery. Her subjective visual deficits and pressure have also resolved. Advantages of the endoscopic approach include improved direct visualization of the lesion, lack of external skin incisions, avoidance of significant neurovascular retraction, and shorter hospital stays than alternative orbitotomy or craniotomy approaches. This 4-handed approach demands endoscopic expertise of 2 surgeons, and is often performed by rhinology-neurosurgery or rhinology-ophthalmology surgical teams. The risk of postoperative diplopia should be discussed with the patient during informed consent. ‡ Anatomic specimen photography courtesy Dr Peris-Celda.