Flashcards in Modern Neuropathology Deck (22)
Definition of tumor:
swelling formed by an abnormal growth of cells
Benign vs malignant tumors
- may be live threatening
- almost never grown back
- have an obvious edge or border
- may become malignant
- always live threatening
- likely to grow back
- may spread to other parts of the body
Brain-related tissues which may grow tumors:
- blood vessels
Most pervasive tumors:
- breast for females
- prostate for males
How prevalent are tumors of the brain and nervous system?
Invasive tumors of the brain and central
nervous system (CNS) rank 13th"highest
in males and 17th highest in females;
however, when the non-invasive brain
and CNS tumors are also included in the
total, the ranks are 11th and 8th highest,
respectively (data not shown)
Mechanisms by which intracranial tumors produce symptoms:
- compression of axons
- destruction of axons
- increasing intracranial pressure (Monro-Kellie doctrine)
General symptoms of intracranial tumors
- headaches (worse in the morning)
- nausea & vomiting
- problems balancing & walking
- changes in mood, personality, concentration
- problems with memory
Focal symptoms of intracranial tumors
- changes in speech, vision, hearing (depending on location)
- muscle jerking, twitching,
- numbness or tingling in arms or legs
- muscle weakness/paralysis
Approaches to diagnosing intracranial tumors
- neurological examination
- imaging (CT/MRI)
- spinal tap
Types of radiation therapy and its side effects:
❖ Classical radiation: Photon
❖ Stereotactic radiation: Gamma-knife
❖ Particle therapy: Proton/Carbon-ion
❖ Radiation-induced meningioma or schwannoma
Most common brain tumors:
3. Vestibular schwannoma
4. Pituitary adenoma
❖ Account for 14-20% of all intracranial neoplasms!
❖ Arise from the arachnoid mater (not dura)!
❖ Women to men ratio of 2:1!
❖ More common in patients > 40 years!
❖ Grade I in 88-95% of cases, rarely grade II or III!
❖ Grows slowly!
❖ Surgery when documented growth on serial imaging and/or symptoms
referable to the lesion
❖ 50% of all intracranial tumors!
❖ Derived from astrocytes: Supporting glial cells!
❖ Grade I to IV
❖ 10 - 15% of astrocytoma!
❖ Epidemiology: Biphasic distribution!
❖ Childhood (6-12y)!
❖ Early adulthood (26-46y)!
❖ Histology benign, but may become malignant!
❖ Rarely cured because they cannot be completely excised
❖ Grade IV: Glioblastoma multiforme (GBM)!
❖ 15-25% of all intracranial tumors!
❖ Rapid growth!
❖ Worst prognosis of all CNS tumors!
❖ Median survival:!
❖ Without treatment: 3 months!
❖ With treatment: 1-2 years!
❖ Therapy: Surgery, Radiotherapy and chemotherapy
Vestibular Schwannoma details
❖ = Acousticus neurinoma!
❖ 5-10% of all intracranial tumors!
❖ Histological benign!
❖ Common early symptom triad:!
❖ Hearing loss!
❖ Follow symptoms, hearing and tumor growth on serial MRI!
❖ Radiation therapy!
Pituitary adenoma details
❖ 15-20% of all intracranial tumors!
❖ Symptoms: !
❖ Hormone oversecretion/underproduction!
❖ Mass effect: !
❖ Compression optic chiasm!
❖ Obstructive hydrocephalus!
❖ Hormone substitution
Types of cancer treatments currently being researched:
❖ Cell lines!
❖ Xenograft model!
❖ GEM model
Gene expression analysis methods used in cancer research:
❖ Quantitative reverse transcriptase PCR!
❖ Next generation sequencing!
❖ Genechip microarray!
❖ Mass spectrometer
Viruses in cancer:
❖ Viruses cause cancer by interfering with cell-cycle controls
❖ Papillomavirus binds to the protein products of two key tumor suppressor genes, Rb and p53, putting them out of action
❖ Elimination of these proteins allows the abnormal cell to survive, divide and accumulate more abnormalities
There are many oncoviruses known:
❖ Human papillomavirus
❖ Epstein-Bar virus
❖ Merkel cell polyomavirus
Three common models for pre-clinical testing of cancer therapeutic agents
❖ Cell lines!
❖ Xenograft model!
❖ GEM model
Using cell lines - pros & cons
❖ Tumor cells can be brought into culture!
❖ Represents the original tumor!
❖ Can be used to test therapeutic agents!
❖ Relatively cheap !
❖ Many different conditions can be tested in small well plates!
❖ Cells can be frozen en thawed for later use!
❖ Genotypic and phenotypic drift!
❖ No histology
❖ Tumor cells injected subcutaneously in athymic, nude mice!
❖ Testing of therapeutic agents!
❖ Testing of drug response does often not correlate with clinical activity in patients