Neuroendoscopic biopsy of tectal glioma: a case report.

OBJECTIVE AND IMPORTANCE: A type of intrinsic dorsal midbrain glioma known as benign tectal glioma can cause obstructive hydrocephalus. Because of its slow progress and relatively good prognosis, initial treatment should be cerebrospinal fluid diversion and biopsy.

CLINICAL PRESENTATION: We report a 24-year-old man with obstructive hydrocephalus from a tectal glioma, who was admitted to the hospital for malfunction of a shunt placed 16 years previously.

INTERVENTION: Magnetic resonance imaging demonstrated enlargement of the dorsal midbrain associated with increased signal intensity on T2-weighted images and fluid attenuation inversion recovery (FLAIR) images. No enhancement occurred with contrast administration. We performed a neuroendoscopic third ventriculostomy and biopsy of the tumor. Histologic examination of the specimen obtained disclosed a low-grade astrocytoma. No postoperative neurologic complications occurred.

CONCLUSION: FLAIR images were superior to T2-weighted images in demonstrating abnormal intensity in the dorsal midbrain. Neuroendoscopy confirmed a yellowish tumor inferior to the posterior commissure occluding the entrance of the aqueduct, an observation useful in planning biopsy of the lesion. As the tumor apparently had existed for a number of years, the case supports the notion that the prognosis associated with these tumors is good.