1/63. Neurotologic follow-up after radiation of posterior fossa tumors. OBJECTIVE: Stereotactic radiation treatment, also known as gamma knife surgery or radiosurgery, has come into acceptance as a treatment alternative to surgical removal for posterior fossa tumors. The purpose of this article is to describe the role of the neurotologist in the optimal management of neurotologic complications after stereotactic radiation, as illustrated by five patients. STUDY DESIGN: Retrospective chart review. patients: Five patients who underwent stereotactic radiation of posterior fossa tumors. MAIN OUTCOME MEASURES: Presence or absence of neurotologic complications (tumor growth, hearing loss, imbalance/ataxia, vertigo, and facial paralysis) or neurosurgical complaints (facial numbness, motor weakness, headache, hydrocephalus, and subarachnoid cysts). RESULTS: Postradiation neurotologic complaints included vertigo, imbalance/ataxia, and progressive hearing loss in four of the five patients. Continued tumor growth occurred in two patients; two patients had no growth; in one patient the tumor became smaller. The complications of facial nerve paralysis, facial numbness, motor weakness, headache, hydrocephalus, cerebellar edema, and posterior fossa arachnoid cyst formation occurred less frequently. CONCLUSIONS: Stereotactic radiation of posterior fossa tumors can produce significant neurotologic problems. It is imperative that neurotologists remain involved in the follow-up care of patients with posterior fossa tumors to offer optimal treatment alternatives for the neurotologic disorders. ( info) |
2/63. Exophytic juvenile pilocytic astrocytomas of the posterior fossa. In children, posterior fossa juvenile pilocytic astrocytomas are common tumors. Radiologically, primarily extra-axial brainstem pilocytic astrocytomas are uncommon and extra-axial cerebellar pilocytic tumors are exceptional. We report two cases of such exophytic tumors, contrasting their presentation, imaging appearance, and prognosis. We also report the radiographic features of posterior fossa juvenile pilocytic astrocytomas from a 5-year review of our institutional experience. ( info) |
3/63. ependymoma with extensive lipidization mimicking adipose tissue: a report of five cases. Lipomatous ependymoma is a recently described entity and only 3 cases of this variant have been reported in the literature. We report 5 cases of this rare variant of ependymoma. patients age ranged from 4 years to 45 years and, interestingly, all of them were males. Two tumors were supratentorial in location, 2 in the fourth ventricle and 1 was intramedullary. Microscopically all of them showed the classical histology of ependymoma along with lipomatous differentiation. The lipomatous component was composed of cells with a large clear vacuole pushing the nucleus to the periphery and giving a signet ring cell appearance. This component demonstrated positivity for GFAP and S-100 protein thereby confirming its glial lineage. Three of the 5 tumors were high grade (WHO-grade III), had a high MIB-1 labelling index (MIB-1 LI) and showed recurrence on follow-up. However, 2 were low grade (WHO grade II) and patients are free of disease till the last follow up. ( info) |
4/63. Anaesthetic management of a child with a positive family history of malignant hyperthermia for posterior fossa surgery in the sitting position. A 6-year-old boy with a positive family history of malignant hyperthermia presented for posterior fossa craniectomy and excision of medulloblastoma. A nontriggering anaesthetic was therefore planned using infusions of propofol and remifentanil and a vapour free anaesthetic system delivering an oxygen/air mixture. The surgery was carried out with the child in the sitting position. ( info) |
5/63. Relative pupil-sparing oculomotor nerve palsy as the presenting sign of posterior fossa meningioma. We report a case of relative pupil-sparing oculomotor paresis initially attributed to ischemia because weakness of other cranial nerves was minimal and dismissed as insignificant. neuroimaging eventually revealed a posterior fossa meningioma. The neurologic symptoms and signs disappeared immediately after resection of the tumor. The third nerve palsy was attributed to deformation of the brainstem. This case reinforces the importance of neuroimaging even in patients who have apparently isolated oculomotor palsy with features not classic for an ischemic etiology. ( info) |
6/63. Unusual imaging appearance of an intracranial dermoid cyst. Intracranial dermoid cysts have characteristic CT and MR imaging findings that generally make preoperative diagnosis straightforward. Enhancement of uncomplicated intradural dermoid cysts on CT or MR studies has been reported but is rare. We present a case of a posterior fossa dermoid cyst that was not only hyperattenuating on CT scans but also contained a mural nodule with clear evidence of enhancement on MR images. ( info) |
7/63. Segmental myoclonus as the sole manifestation of a choroid plexus papilloma in the posterior fossa. Case report. The authors describe the case of a 22-year-old woman with involuntary contractions of the sternocleidomastoid and trapezius muscles that resulted in turning movements of the head. The jerks displayed the clinical and neurophysiological characteristics of segmental myoclonus (SM) restricted to muscles supplied bilaterally by the first four cervical segments. magnetic resonance imaging disclosed a tumor in the midline above the cisterna magna that was later histologically proven to be a choroid plexus papilloma. The patient's involuntary movements did not extend to other muscle groups or, in particular, to the palate, as one might have expected in the case of brainstem lesions. myoclonus was the sole clinical manifestation of the tumor in this patient; other signs and symptoms invariably reported in other cases of posterior fossa papilloma, such as increased intracranial pressure or cranial nerve palsies, were absent. Release from suprasegmental control is suggested as a possible pathophysiological mechanism in this case of SM. ( info) |
8/63. Peduncular hallucinations associated with large posterior fossa meningiomas. Peduncular hallucinosis may be observed in patients with thalamic or brain stem ischemia or hemorrhage, while it has been less often described in association with brain stem or cerebellar tumors. We report in this paper two cases associated with large posterior fossa meningiomas. In the first patient hallucinosis appeared preoperatively as a result of brain stem compression and ceased after the tumor removal. In the second patient hallucinosis occurred after the surgery, as a result of surgical trauma with local brain stem edema, and ceased 4 days after treatment with desamethasone and carbamazepine. ( info) |
9/63. Long-term treatment with ketamine in a 12-year-old girl with severe neuropathic pain caused by a cervical spinal tumor. A 12-year-old girl presented with head and neck pain, myoclonic movements, and decreased strength in all extremities caused by a cervical spinal tumor (glioblastoma multiforme). A partial resection of the tumor was performed. Three weeks later, she had superficial pain distributed in all dermatomes below her cervical medullary lesion. touch (e.g., gentle hugs from relatives) and movements elicited paroxysm of intense pain. The pain was not relieved by increased doses of morphine. A test dose of ketamine (7.5 mg intravenous) provided an abrupt decrease in pain intensity, and continuous infusions of subcutaneous morphine and intravenous ketamine were started. benzodiazepines were administered to avoid psychotomimetic effects from ketamine and to diminish myoclonic movements. The doses of analgesics and benzodiazepines were increasingly titrated (subcutaneous morphine 163-750 mg/24 hr, intravenous ketamine 36-410 mg/24 hr, subcutaneous midazolam 5-20 mg/24 hr, and intravenous diazepam 11.5-122.5 mg/24 hr) until her death 67 days after start of ketamine. She remained awake until the last day before her death. For the last 29 days of life, the pain treatment regimen was successfully continued in her home (400-km distance from the hospital). In conclusion, this case demonstrates that ketamine treatment may be effective in children with severe neuropathic pain not responsive to other analgesics. This patient also demonstrates the feasibility of long-term ketamine treatment in pediatric oncology and that such treatment can be administered in a home care setting. ( info) |
10/63. A rare symptomatic presentation of ecchordosis physaliphora and unique endoscope-assisted surgical management. We report on the presentation, diagnosis, and surgical management of a rare symptomatic case of ecchordosis physaliphora, including the use of endoscopy as a valuable imaging device in its operative management. A 49-year-old male presented with a intradural extra-axial mass located to the left of the basilar artery in the prepontine space. The tumor was exposed via a transmaxillary transclival approach and resected under binocular microscopic visualization. Prior to and following resection, endoscopes were introduced into the surgical field to conduct anatomic surveys of the region and to assess the completeness of tumor removal. Ecchordosis physaliphora is an uncommon benign lesion originating from embryonic notochordal remnants. It rarely causes clinical symptoms due to its slow growth patterns. Although similarities between EP of the spheno-occiput and chordomas of the clivus make distinction obscure, differentiation is important. Differences in these lesions impact upon patient prognosis as well as therapeutic strategies. The use of endoscopy in the resection of this mass marks an innovative approach to intraoperative imaging of the clival region; improved visualization of the prepontine area allows for more accurate defintion of the surgical anatomy of the tumor and for thorough assessment of the completeness of tumor removal. ( info) |