Abnormal Schwannoma-like Growth of multiple, multifocal BRAF V600E-positive Glioblastoma in the Interior Acoustic Canal with Leptomeningeal Infiltration: a case report.

BACKGROUND: Glioblastoma belongs to the most common and most aggressive tumor entity of the central nervous system with a poor prognosis of only few months. Once manifested, it grows fast and diffusely by infiltrating the surrounding brain parenchyma. Despite its aggressive behavior, glioblastoma rarely presents with multiple lesions and metastasis to intra- and extracranial tissues. Therefore, metastasized, multiple glioblastoma is limited to case reports. Our case describes an atypical primary bilateral manifestation of BRAF V600E-positive epithelioid glioblastoma with rapid metastasis and meningeosis glioblastoma while under adjuvant chemoradiotherapy. CASE PRESENTATION: A 60-year-old Caucasian male patient presented with a seizure and numbness in his left arm. He was diagnosed with an abnormal primary bilateral manifestation of multiple, multifocal BRAF V600E-positive and isocitrate dehydrogenase (IDH) wild-type intracranial epithelioid glioblastoma with O6-methylguanine-DNA methyltransferase methylation (MGMT) at 12%. While being under the adjuvant chemoradiotherapy with temozolomide, the patient developed left-sided facial nerve weakness and hearing loss, dysarthria, and severe gait instability. Cranial magnetic resonance imaging showed that glioblastoma lesions advanced rapidly with a schwannoma-like growth pattern by invading the left internal acoustic meatus, adjacent cranial nerves, and leptomeninges. A lumbar puncture confirmed meningeosis glioblastoma. Four months after the initial diagnosis of glioblastoma, the patient died from the complications of the fast and diffuse metastasis. CONCLUSIONS: Glioblastoma rarely presents with metastases despite its aggressive and rapidly growing nature. Our case should increase awareness of symptom tracking in patients with glioblastoma to intervene early and efficiently. Moreover, refractory therapies for glioblastoma should underline the importance of personalized medicine.