Histology · Year 1 · from Histology
Case 2: Glioblastoma
Clinical Image
Source: Wikipedia - Glioblastoma - CC BY-SA 3.0
Case Presentation
A 62-year-old man presents with a 6-week history of progressive headache, confusion, and left-sided weakness. His wife reports personality changes with apathy and poor judgment. Neurological examination reveals left hemiparesis, left homonymous hemianopia, and expressive aphasia. MRI brain reveals a large, heterogeneous, ring-enhancing mass in the right frontotemporal region with central necrosis, surrounding vasogenic edema, and mass effect with midline shift. The enhancement pattern reflects breakdown of the blood-brain barrier due to abnormal tumor vasculature. Stereotactic biopsy is performed. Histopathology shows markedly pleomorphic cells with nuclear atypia, high mitotic activity, microvascular proliferation, and areas of pseudopalisading necrosis (tumor cells arranged around necrotic foci) - all hallmarks of glioblastoma. GFAP immunostaining is positive, confirming astrocytic origin. Molecular testing shows IDH-wildtype status. The diagnosis is glioblastoma (WHO grade 4). Despite aggressive treatment with surgery, radiation, and temozolomide chemotherapy, the prognosis is poor with median survival of approximately 15 months.
Key Learning Points
- Glioblastoma arises from astrocytes, identified by GFAP (glial fibrillary acidic protein) expression
- The tumor's aggressive behavior reflects rapid proliferation and neovascularization with abnormal blood-brain barrier
- Pseudopalisading necrosis (viable tumor cells surrounding necrotic areas) is a histological hallmark
- The blood-brain barrier, normally maintained by astrocyte end-feet and specialized endothelium, breaks down in tumors
- Understanding astrocyte markers (GFAP) and function (blood-brain barrier maintenance) is essential for tumor classification