Brain Tumor: An Overview of Introduction, Types, Pathogenesis

Introduction

Table of Contents

A brain tumor is an abnormal, uncontrolled growth of cells within the brain or its surrounding structures. Brain tumors may be primary (originating in the brain) or secondary (metastatic), spreading from other organs. They can affect individuals of any age and cause significant neurological morbidity.

Types of Brain Tumors

1. Primary Brain Tumors

Gliomas (astrocytoma, glioblastoma, oligodendroglioma)
Meningioma
Pituitary adenoma
Schwannoma
Medulloblastoma
Ependymoma

2. Secondary (Metastatic) Brain Tumors

Metastases from lung, breast, melanoma, kidney, and colon cancers

Pathogenesis

Brain tumor development involves genetic and molecular alterations leading to uncontrolled cell proliferation:

Activation of oncogenes (EGFR, BRAF)
Inactivation of tumor suppressor genes (TP53, RB)
IDH mutations in lower-grade gliomas
Abnormal signaling pathways (PI3K/AKT/mTOR)
Tumor-induced angiogenesis and blood–brain barrier disruption

Laboratory Diagnosis

Neuroimaging: MRI with contrast (gold standard), CT scan
Histopathology: Tumor grading and classification (WHO classification)
Immunohistochemistry: GFAP, Ki-67, IDH1, p53
Molecular testing: IDH mutation, 1p/19q co-deletion, MGMT methylation
CSF examination (selected tumors)

Treatment

Surgical resection (maximal safe removal)
Radiotherapy
Chemotherapy (temozolomide)
Targeted therapy and immunotherapy
Steroids for cerebral edema
Antiepileptics for seizure control

Prevention

Avoidance of ionizing radiation
Use of protective measures in occupational exposure
Early evaluation of persistent neurological symptoms
Genetic counseling in familial tumor syndromes

Keynotes

Brain tumors may be benign or malignant, but both can be life-threatening.
MRI is the imaging modality of choice.
Molecular profiling guides prognosis and therapy.
Multidisciplinary management improves outcomes.
Early diagnosis is critical for better survival and quality of life.

Brain Tumor: An Overview of Introduction, Types, Pathogenesis, Lab Diagnosis, Treatment, Prevention, and Keynotes