Management strategy for adult patients with dorsal midbrain gliomas

Dorsal midbrain gliomas (DMGs) involving the tectum occur more commonly in children than in adults. These lesions are often indolent in nature, and patients require treatment only for obstructive hydrocephalus. Because limited information is available concerning adults with this type of lesion, we describe our experience and management strategy in adults with DMGs.

We retrospectively reviewed the charts and magnetic resonance imaging scans of five adult patients (four men, one woman; mean age, 51.6 yr; range, 23-69 yr) who were treated from March 1992 to August 2001 for DMGs involving the tectum. The mean follow-up time for these patients was 71.4 months (range, 25-113 mo). We analyzed the data to determine the optimal treatment strategy and outcomes of patients with DMGs. Tumor volume was analyzed objectively with Scion Image software (Scion Corp., Frederick, MD) to document changes in volume and determine whether treatment strategy differed significantly with tumor size.

Tumors in two of these patients were found incidentally, and three others presented with obstructive hydrocephalus. Magnetic resonance imaging scans demonstrated an isolated tectal glioma in one patient, tectal and tegmental (periaqueductal) gliomas in three patients, and a tectal glioma with right thalamic extension in one patient. Treatment consisted of routine follow-up for the two asymptomatic patients and cerebrospinal fluid diversion surgery for the three patients with hydrocephalus. Volumetric analysis demonstrated that all asymptomatic patients had tumors smaller than 9.3 cm(3), and symptomatic patients had tumors larger than 28.5 cm(3). All follow-up magnetic resonance imaging scans revealed stable dorsal midbrain lesions, and no patient required tumor-specific therapy.

Although tumors of the dorsal midbrain occur primarily in the pediatric population, similar tumors may occur in adults. As has been learned from experience with children, these lesions are often clinically and radiographically stable and require only appropriate therapy for obstructive hydrocephalus. We advocate a similar conservative strategy of routine imaging follow-up and treatment for hydrocephalus in adult patients. Surgery and other therapy should be reserved for patients with progressive lesions.