ED-06 * BRAINSTEM GLIOMAS IN ADULTS: DO ADULT DIFFUSE INTRINSIC PONTINE GLIOMAS EXIST?

Abstract

BACKGROUND: The majority of brainstem tumors in children are diffuse intrinsic pontine gliomas (DIPG), and are diagnosed in middle childhood. Recent data suggests DIPG is a disease of development. Relatively little information is available for adult brainstem gliomas (BSG). We reviewed clinical and radiographic information from adults with BSG referred to our institution. METHODS: Patients were enrolled on IRB-approved protocols. Clinical data was obtained from patient charts and electronic records. Radiographic data was reviewed on a Picture Archiving and Communications System (PACS) and assessed for primary tumor location, enhancement, intensity on T1, invasion of surrounding anatomical structures, and presence of CNS disease outside of the brainstem. RESULTS: 18 patients diagnosed with BSG were identified; diagnostic MRI was available for review on 15. M:F was 16:2; median age 29.5 (range 16-71) years at diagnosis. Presenting symptoms included long tract signs (61%), diplopia (50%), other visual changes (22%), imbalance (44%), headache (33%) and nausea/vomiting (33%). Primary tumor location varied: 27% were located in the pons only, 33% in pons with extension to medulla, 13% in pons with extension to midbrain, and 20% in pons with extension to midbrain and medulla. 80% showed contrast enhancement, with the majority (58%) of these enhanced diffusely. Other radiographic findings included encasement of the basilar artery (20%) and evidence of CNS disease outside of the brainstem (20%) at diagnosis (cerebellum and parietal lobe). The majority (88%) received radiation treatment; 56% received concurrent chemotherapy and 44% received adjuvant chemotherapy. Median time to first progression (defined radiographically and clinically) was 22 months (range 3-192 months). CONCLUSIONS: Although adults with brainstem tumors involving the pons have similar presentation as children with DIPG, imaging findings and clinical outcome differ significantly. Investigation into the biology of the adult lesions, including H3.3 mutations, may help define these as more distinct entities.