How is glioblastoma diagnosed?

Glioblastoma (GBM) is the most common malignant brain tumor, and diagnostic accuracy is crucial to the development of treatment plans. DiagnosisGBMusually includes multiple steps such as medical history collection, physical examination, imaging examination and pathological testing. The following is a detailed introduction to the specific process:

1. Medical history collection

The doctor will ask the patient in detail about the onset, duration and development of symptoms. Common symptoms include headache, seizures, nausea, vomiting, memory loss, limb weakness and visual impairment. The patient's age, past medical history, family history, and occupational exposure may also provide clues to the diagnosis.

2. Nervous system physical examination

Assess the patient’s brain function impairment through neurological examination, including the following aspects:

Conscious status: Assess for the presence of confusion or drowsiness.

Motor and sensory function: Check for weakness or abnormal sensation in the limbs.

Language ability: Tests the patient's ability to express and understand.

Cranial nerve function: Assess vision, hearing, swallowing, and facial sensation.

Reflex examination: observe changes in deep tendon reflexes, pathological reflexes and other changes.

3. Imaging examination

Imaging is a key step in the diagnosisGBM. The following are commonly used imaging methods:

Magnetic resonance imaging (MRI): MRI is the imaging tool of choice for diagnosing GBM. Enhanced scans can show the size, location and boundaries of the tumor, which typically appear as ring-shaped enhanced lesions with central necrosis and surrounding edema. MRDiffusion-weighted imaging (DWI) and perfusion imaging (PWI) can help assess tumor aggressiveness.

Computed tomography (CT): CT is often used for the initial evaluation of emergency patients, especially when increased intracranial pressure or cerebral hemorrhage is suspected. However, CTCT has low resolution and cannot fully display the details of the tumor.

Positron emission tomography (PET): PET scans can help distinguish malignant tumors from benign lesions and monitor treatment effects and tumor recurrence by detecting tumor metabolic activity.

4. Pathological testing

Pathological examination is the gold standard for confirming the diagnosis of GBM, and samples are usually obtained through surgical biopsy or tumor resection. Here are the key steps:

Histological examination: Observe the morphology of tumor cells through a microscope. GBM often shows high cell density, irregular nuclei, microvascular proliferation and necrotic areas.

Molecular marker detection: Detection of MGMTpromoter methylation status, IDHmutation, TERTmutation, and 1p/19q co-deletion and other molecular features are helpful for further classification and assessment of prognosis.

5. Auxiliary inspection

Cerebrospinal fluid examination: When a tumor combined with meningeal metastasis is suspected, cerebrospinal fluid can be tested through lumbar puncture to look for cancer cells or specific biomarkers.

Genetic testing: Apply next-generation sequencing (NGS) technology to detect tumor-related gene mutations and guide targeted treatment selection.

6. Differential diagnosis

SinceGBM’s symptoms and imaging findings may be similar to other encephalopathies, it needs to be differentiated from the following diseases:

Brain metastases: The presence of multiple lesions and primary tumor lesions suggests the possibility of brain metastases.

Brain abscess: Ring-enhancing lesions, surrounding edema, and fever symptoms are common in abscesses.

Lymphoma: Single lesion accompanied by systemic symptoms (such as fever, night sweats, weight loss) should be considered lymphoma.

The diagnosis of glioblastoma is a systematic process that requires comprehensive evaluation based on the patient's medical history, physical examination, imaging and pathology results. Early and accurate diagnosis buys time for treatment and improves patient survival prognosis.

(Click to view an introduction to drugs for the treatment of glioblastoma.)

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Reference materials

1.National Cancer Institute. Glioblastoma Diagnosis and Imaging. https://www.cancer.gov

2.American Brain Tumor Association. Diagnostic Methods for Brain Tumors.

https://www.abta.org

3.UpToDate. Diagnosis and Differential Diagnosis of Glioblastoma.

https://www.uptodate.com