Anatomical localization of the transverse-sigmoid sinus junction: Comparison of existing techniques.

BACKGROUND: Anatomical localization remains integral to neurosurgery, particularly in the posterior fossa where neuronavigation is less reliable. There have been many attempts to define the location of the transverse- sigmoid sinus junction (TSSJ) using anatomical landmarks, to aid in the placement of the "strategic burr hole" during a retrosigmoid approach. There is a paucity of research allowing direct comparison of such techniques. METHODS: Using high-resolution contrast-enhanced cranial computed tomography images, we constructed three-dimensional virtual cranial models. Fifty models (100 sides) were created from a retrospective sample of images performed in a New Zealand population. Ten methods of anatomical localization were applied to each model allowing qualitative and quantitative comparisons. The "key point" was defined as the point on the outer surface of the skull that directly overlaid the junction of the posterior fossa dura, transverse sinus (TS), and sigmoid sinus (SS). The proximity of each method to this "key point" was compared quantitatively, in addition to other descriptive observations. TSSJ localization methods analyzed included: (1) asterion; (2) emissary foramen; (3) Lang and Samii; (4) Day; (5) Rhoton; (6) Avci; (7) Ribas; (8) Tubbs; (9) Li; and (10) Teranishi. RESULTS: Mean distance to the "key point" showed two tiers of accuracy, those <10 mm, and those >10 mm: Li (6.3 mm), Ribas (6.6 mm), Tubbs (6.8 mm), Teranishi (7.8 mm), Day (8.4 mm), emissary foramen (12.0 mm), Avci (13.0 mm), asterion (13.9 mm), Lang and Samii (15.6 mm), and Rhoton (17.4 mm). The asterion would most frequently overlie the TS (63%) and was often supratentorial (14%). CONCLUSION: Each method has a unique profile of dura or sinus exposure. There are significant differences in the accuracy of localization of the TSSJ among anatomical localization methods.

'Goose bumps' as presenting feature of intraventricular glioblastoma multiforme.

'Goose-bumps' seizures are rare manifestations of epilepsy. They are rarely reported by patients and can be easily dismissed by clinicians. Clinically, it carries some diagnostic localising value especially with unilateral onset. In this report, we present a case of intraventricular glioblastoma multiforme with ipsilateral goose bumps and review the literature.

Occurrence of basal ganglia germ cell tumors without a mass.

OBJECTIVE: To report a case series in which basal ganglia calcifications without mass effect proved to be germ cell tumors. DESIGN: Case series. SETTING: Tertiary care hospital. PATIENTS: Four patients. INTERVENTIONS: Computed tomography, magnetic resonance imaging, positron emission tomography, biopsy, chemotherapy, and radiation therapy. MAIN OUTCOME MEASURES: Recognition of clinical syndrome and radiological features. RESULTS: All patients had progressive hemiparesis, and 1 patient also had frontal lobe dementia. Imaging demonstrated progressive asymmetric signal abnormality with basal ganglia calcification and associated brainstem atrophy. Fludeoxyglucose F 18-positron emission tomography showed hypometabolism in contrast to malignant glioma. CONCLUSION: Germ cell tumor should be considered in patients with an indolently progressive neurological course, particularly if basal ganglia calcification is present with or without enhancement, asymmetric brain atrophy, or a mass.

Epilepsy associated with a cerebellar arachnoid cyst: seizure control following fenestration of the cyst.

OBJECTIVE: The role of the cerebellum in the pathogenesis of seizures remains controversial. Cerebellar origin of seizures, albeit rare, has been described in the literature in association with intrinsic lesions of the cerebellum. We present a unique case of a patient with medically intractable, secondary generalized epilepsy, associated with a superior cerebellar quadrigeminal arachnoid cyst. CLINICAL PRESENTATION: A 9-year-old child presented with medically refractory secondary generalized epilepsy associated with recurrent headaches since 6 months of age. The child also had moderate intellectual impairment and autism. On the magnetic resonance imaging (MRI) of the head, he was noticed to have a small superior cerebellar arachnoid cyst in the quadrigeminal area that had increased in size slightly. Interictal electroencephalograph (EEG) was unable to localize the site of the epilepsy. Neurological examination was unremarkable. INTERVENTION: A suboccipital craniotomy and supracerebellar infratentorial approach to the cyst was performed at 9 years of age. Intraoperative electrocorticography (ECOG) demonstrated epileptic activity from the cerebellar tissue adjacent to the cyst. The cyst was fenestrated, and the cyst wall was sent for histology. Seizure control improved dramatically after fenestration of the cyst. CONCLUSION: This case provides strong evidence that, albeit rare, the cerebellum may be a source of epileptic activity due to compression by a lesion in the posterior fossa. Hence, in cases with intractable epilepsy of unknown supratentorial source, the differential diagnosis should include a posterior fossa lesion. The finding of a posterior fossa lesion in such cases, even if it is small and appears benign, should precipitate a discussion about the possible relationship between the posterior fossa lesion and the epilepsy.

Aneurysmal bone cysts of the cranium in children. Report of three cases and brief review of the literature.

Aneurysmal bone cysts (ABCs) of the cranium in children are rare, with only 3 to 6% of cases occurring in this anatomical location. Consequently, not much is known about ABCs and the most effective modality of treatment. The authors present the cases of three patients with ABCs and discuss the origin, pathogenesis, clinical presentation, pathological features, and imaging characteristics of these lesions. Furthermore the authors review the literature to find out the current treatment options for these lesions.