NI-80 CASE REPORT: TREATMENT RESPONSE IN LEPTOMENINGEAL CARCINOMATOSIS FROM GLIOMATOSIS CEREBRI TREATED WITH BEVACIZUMAB (AVASTIN)

Gliomatosis cerebri (GC) is a diffuse glioma, usually astrocytic with remarkable infiltration in at least 3 cerebral lobes considered a Grade III tumor according to WHO classification. Leptomeningeal gliomatosis(LG) occurs in 17% of patients with GC, although reported as microscopic dissemination in up to 70% of post-mortem studies amongst all gliomas. GC is a very rare and aggressive glioma, while, leptomeningeal metastasis is a severe complication of malignancy, both presenting with very poor prognosis. There is limited data on standard of care for these patients. Bevacizumab is an anti-angiogenic drug approved for treatment of malignant gliomas. Studies have shown prolongation of progression-free survival and improvement of quality of life. There are a few reports of Avastin being used for GC or LG. We report a case of a 52 year-old male presenting with 3 weeks of nausea and vomiting, preceded by 12 months of mild cognitive decline. MRI studies revealed extensive areas abnormal Flair signal and diffuse leptomeningeal enhancement seen throughout the brain and spinal cord. Diagnosis of GC with leptomeningeal dissemination was confirmed with brain biopsy. The patient completed radiotherapy and received Temozolomide, in addition to 6 intrathecal cytarabine injections. A repeat MRI showed progression of disease and therapy was switched to Avastin. We monitored his progress with serial MRI's, which revealed marked decrease in size and enhancement of previous lesions, consistent with a response to Avastin. The patient remained clinically stable during this interval. A literature review of patients already on Avastin for systemic malignancies revealed some case reports of patients progressing to LG. A decrease in enhancement of lesions was also observed in these patients. However, there are few reported cases of leptomeningeal carcinomatosis secondary to GC. These MRI changes may be clinically relevant and additional studies are required to further investigate a correlation.