TMOD-20. CASE REPORT: THE ODYSSEY TO THE RIGHT DIAGNOSIS. SURPRISING GLIOBLASTOMA MIMICS

Abstract

Abstract A 57-year-old female presented at the emergency room with acute onset aphasia but unremarkable cCT (incl. angiography and perfusion). Suspecting an ischemic stroke, she received thrombolysis with quick recovery of aphasia. Afterwards, myoclonic jerks of the face and right arm occurred leading to anticonvulsant therapy. Follow-up cMRI surprisingly demonstrated swollen T2w-hyperintense and Gd-enhancing left limbic, temporal and frontal lobes. Suspected herpes-simplex-encephalitis was treated with aciclovir despite unremarkable CSF results (no pleocytosis, no BBB disruption, negative HSV-PCR) on day 2 and follow-up (day 5). Due to persisting cognitive deficits, autoimmune limbic encephalitis was suspected, and intravenous immunoglobulin therapy was added. Three weeks later, she experienced new neurological symptoms (weakness, blurred vision, vomiting, headache). Follow-up brain MRI demonstrated a massive increase of multifocal Gd-enhancing lesions. Partial resection revealed the diagnosis of an IDH-wildtype glioblastoma (GB). Next generation oncogene panel testing demonstrated a GOPC-ROS1 fusion which is rarely found in GB. Due to the gliomatosis-like infiltration of both hemispheres, radiotherapy was deemed to be too toxic. Instead, she received two cycles of lomustine in absence of a MGMT-promotor methylation. Two months later cMRI showed a symptomatic second multilocular progression. 2nd-line therapy with a ROS-inhibitor was rejected, whereupon she died five weeks later. Our case is in several aspects peculiar: It demonstrates that rare GB-mimics (i.e. HSV- and autoimmune limbic encephalitis) can only be ruled out in a fast manner by brain biopsy. Watchful waiting may neglect fast progression of GB leading to the inability to provide optimal treatment (i.e. radiotherapy). Thrombolysis is strictly contraindicated in primary brain tumors, but was unharmful in our case most probably to the early tumor stage without relevant neoangiogenesis. Rare genetic abnormalities like ROS1-fusions which are reported mostly in childhood glioblastoma may be present and serve as a therapeutic target also in adult GB.