Optic pathway glioma: correlation of imaging findings with the presence of neurofibromatosis.

BACKGROUND AND PURPOSE: Despite the benign histology of optic pathway glioma (OPG) (low-grade astrocytoma), its biological behavior is unpredictable, and it is unclear whether specific morphologic or anatomic patterns may be predictive of prognosis. It is also unclear whether OPG associated with neurofibromatosis (NF) is a distinct entity from non-NF-OPG. Our purpose was to describe the MR imaging features of OPG, compare the findings between patients with and those without NF, and identify prognostic imaging signs. METHODS: MR examinations of 91 patients with OPG (47 with NF and 44 without) were reviewed at presentation and during follow-up. The images were evaluated for size and extension of tumor, and imaging parameters. Statistical bivariate analysis was used to compare the patients with and those without NF, and Pearson correlation was used to evaluate the correlation between the different imaging parameters and prognosis. Kappa values were calculated to determine intraobserver and interobserver variability. RESULTS: The most common site of involvement in the NF group was the orbital nerve (66%), followed by the chiasm (62%). In the non-NF group, the chiasm was the most common site of involvement (91%); the orbital nerves were involved in only 32%. Extension beyond the optic pathway at diagnosis was uncommon in the NF group (2%) but frequent in the non-NF group (68%). In the NF group, the tumor was smaller and the original shape of the optic pathways was preserved (91% vs. 27% in the non-NF group). The presence of cystic components was significantly more common in the non-NF patients (66% vs. 9% in the NF group). During follow-up, half the NF patients remained stable, in contrast to 5% of the non-NF group. No statistical correlation was found between imaging features and biological behavior of the tumor. CONCLUSION: NF-OPG is a separate entity from non-NF-OPG, with different imaging features and prognosis, thereby warranting a specific diagnostic, clinical, and therapeutic approach.

Intracranial cavernous hemangioma in a neonate.

Cogenital intracranial hemangioma is rare, and the imaging findings have been described in very few cases. We describe a case of a huge congenital left parietal hemangioma that was diagnosed postnatally by head duplex ultrasonography. Complete surgical resection yielded an excellent outcome.

Optic chiasm glioma, electrolyte abnormalities, nonobstructive hydrocephalus and ascites.

A 4-year-old girl with optic chiasm glioma (OCG), nonobstructive hydrocephalus and ventriculoperitoneal shunt is described, in whom marked ascites developed. The ascitic fluid was protein-rich and its amount correlated with cerebrospinal fluid (CSF) protein. The CSF protein level and the amount of ascitic fluid were influenced by chemotherapy. Very unusual hypernatremia, up to 190 mEq/l with no associated alteration in mental status, was also found. It is suggested that altered absorption ability owing to the high protein content was the cause of both the nonobstructive hydrocephalus and the ascites. The unusual well being with very high sodium concentrations may have resulted from osmoreceptor dysfunction, presumably caused by hypothalamic involvement as well as by the high CSF protein. This combination of findings may point toward specific characteristics of OCG. In an effort to reduce the amount of the ascitic fluid, a further chemotherapeutic trial may be done, before converting the shunt to the vetriculoatrial system.