clinmed2test3: CNS Neoplasms ppt

Primary CNS Tumors

• Primary CNS tumors originate in the brain or spinal cord, whereas secondary CNS tumors metastasize from cancers in other organs.
• Most common primary brain tumor is meningioma, while most common malignant primary brain tumor is glioblastoma.
• Most common brain tumor overall is metastatic cancer from another source.

Risk Factors

• Occupation: white collar professionals, healthcare, and lab research.
• Exposure to ionizing radiation, therapeutic radiation therapy, and history of head trauma.
• Environmental exposure to N-nitroso compounds, genetic predisposition (neurofibromatosis types 1 & 2), and radiofrequency radiation and electromagnetic radiation exposure.

Metastatic Intracranial Tumors

• Cancer originates elsewhere in the body and metastasizes to the brain via blood.
• Most common brain tumors in adults, with 4-10 times more frequent occurrence than primary brain tumors.
• Usually multiple lesions, with cancers most likely to spread to the brain being lung, breast, melanoma, renal cell, and colon.

Classification of Primary Brain Tumors

Meningioma

• Attached to the dura mater, slow-growing tumors with a strong female predominance.
• Consider neurofibromatosis, often asymptomatic, with surgery as the main treatment.
• Problems arise from pressure, with visual complications if affecting optic nerve tract, and seizures in 25-40% of patients.

Acoustic Neuroma

• Also known as vestibular schwannoma, arising from the vestibular portion of CN VIII.
• Median age at diagnosis is 50, with unilateral cases in more than 90% of cases.
• Bilateral vestibular schwannomas suggest neurofibromatosis type 2 until proven otherwise.
• Risk factors include familial or genetic risk, noise exposure, and leisure settings (OR=1.9) and work (OR=1.5).
• Clinical presentation includes asymmetric sensorineural hearing loss with or without other focal cranial nerve deficits, confirmed with audiometry and imaged with MRI or CT.

Glioblastoma

• Most common primary malignant brain tumor, with usual age-of-onset above 60.
• Usually located in cerebral white matter, with heterogeneous cellular origins.
• Characterized by necrosis with vascular proliferation, forming a "ring of tissue around necrotic core".

Glioma

• Catch-all term for tumors originating from glial cells (neural structural/support cells).
• Includes astrocytoma, glioblastoma, and oligodendroglioma.
• Graded by the presence or absence of standard pathologic features (WHO Grades I-IV).

Clinical Presentation of Brain Tumors

• Headaches in 20% of cases, typically worst on rising in the morning.
• Seizures in 35% of cases, with presentation depending on location.
• Can mimic stroke, with clinical features evaluated through CT and/or MRI, EEG, surgery, and radiation therapy.

Sequelae of Brain Tumors

• Cognitive dysfunction, frontal personality, and loss of social inhibition.
• Left hemispheric tumors: language dysfunction.
• Right hemispheric tumors: problems with visual perception and scanning.