Faculty Bibliography

A choroid plexus papilloma is a rare CNS neoplasm arising from the neuroepithelial lining of the choroid plexus. A third ventricular location of a choroid plexus papilloma is rare compared with the more common sites in the lateral and fourth ventricles. Cystic choroid plexus papilloma represents an infrequent subtype that may present diagnostic ambiguity. The authors present a case of cystic choroid plexus papilloma within a cavum septum pellucidum that radiographically mimicked neurocysticercosis

OBJECT: The choice of surgical approach during resection of a thalamic juvenile pilocytic astrocytoma (JPA) is dictated by the location of the displaced normal thalamus and posterior limb of the internal capsule (PLIC). Diffusion tensor (DT) imaging and white matter tractography can identify the location of the PLIC in relation to the tumor and may be useful in planning the operative trajectory. METHODS: Diffusion tensor imaging was used to localize the PLIC on preoperative MR imaging in 6 children undergoing resection of thalamic JPAs. After review of the standard T2-weighted MR imaging sequences, the anticipated position of the PLIC was determined. This result was compared with the location of the PLIC determined by a blinded radiologist with the use of DT imaging. The utility of DT imaging in determining the surgical approach to a thalamic JPA, degree of resection, and neurological outcomes were all evaluated. RESULTS: Diffusion tensor imaging confirmed the expected location of the PLIC as approximated on conventional T2-weighted images in all 6 cases. In 1 patient in particular, unexpected medial deviation of the PLIC was identified, and this proved useful in tailoring the approach to a more lateral trajectory. Gross-total resection of all cystic and solid tumor components was confirmed on postoperative imaging in all cases. All patients experienced mild to moderate worsening of neurological status immediately following resection, but 4 of 6 patients were back to their preoperative baseline at 6-month follow-up. CONCLUSIONS: Diffusion tensor imaging and white matter tractography successfully identified the white matter fibers emanating from the precentral gyrus within the PLIC in children with thalamic JPAs prior to surgery. Diffusion tensor imaging served as a valuable tool for stereotactic planning of operative approaches to thalamic JPAs. Localizing the position of the PLIC helped minimize potential neurological morbidity and facilitated gross-total resection

Patients with symptomatic Chiari malformation Type I (CM-I) typically exhibit a chronic, slowly progressive disease course with evolution of symptoms. However, some authors have reported acute neurological deterioration in the setting of CM-I and acquired Chiari malformations. Although brainstem dysfunction has been documented in patients with CM-II and hydrocephalus or shunt malfunction, to the authors' knowledge only 1 report describing ventriculoperitoneal (VP) shunt malfunction causing neurological deterioration in a patient with CM-I exists. The authors report on their experience with the treatment of previously asymptomatic CM-I in 2 children who experienced quite different manifestations of acute neurological deterioration secondary to VP shunt malfunction. Presumably, VP shunt malfunction created a positive rostral pressure gradient across a stenotic foramen magnum, resulting in tetraparesis from foramen magnum syndrome in 1 patient and acute ataxia and cranial nerve deficits from syringobulbia in the other. Although urgent shunt revisions yielded partial recovery of neurological function in both patients, marked improvement occurred only after posterior fossa decompression

Local recurrence following radical resection is one of the most common complications of pediatric craniopharyngioma. Only 28 cases of ectopic recurrence of craniopharyngioma have been reported in the literature, and only 13 cases occurred in patients originally treated as children. In this consecutive series of 86 children who underwent radical resection of primary and recurrent craniopharyngiomas, 4 patients (4.7%) experienced ectopic tumor recurrence, accounting for 27% of all recurrences after gross-total resection. The authors report on the successful surgical treatment of these 4 patients and the impact of ectopic craniopharyngioma recurrence on survival

We present a case of synchronous involvement of the pineal and suprasellar regions by a mixed germ cell tumor comprising germinoma and yolk sac tumor components, with a predominant angiomatous component. To our knowledge, it is the first case of this nature to be reported in the literature. Usually, synchronous lesions of this kind are pure germinomas, and some clinicians will forgo a biopsy and assume a germinoma histology if the serum beta-human chorionic gonadotrophin (HCG) is <50 IU/l and the alpha-fetoprotein (AFP) is within normal limits. Secondly, if a biopsy is performed on a lesion that has a prominent angiomatous component, the diagnostic germ cell tumor may be missed at the time of the biopsy. In order to alert clinicians and pathologists to this rare entity, the case is discussed with particular reference to difficulties that were encountered in rendering an accurate diagnosis, and the associated management implications