Histopathological Analysis and Ki-67 Expression in Various Central Nervous System Tumors.

Martina, V (2013) Histopathological Analysis and Ki-67 Expression in Various Central Nervous System Tumors. Masters thesis, Thanjavur Medical College, Thanjavur.


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The Central Nervous System Is Made Up Of The Brain And The Spinal Cord And Their Coverings . They Are Unique In Their Ability To Receive, Store And Transmit Information. Brain Tumors Though Not Frequent Contribute Significantly To Morbidity Because Of The Mental Alterations, Neurological Deficits And Their Relatively Poor Survival Rate. Hence The Social Burden Of The Central Nervous System Tumors Is Just As Large As That Of Other Tumors. The Central Nervous System Tumors Are Unique In A Way That It Has Some Special Features. In Contrast To Other Sites Benign Tumors May Have The Potential To Become Life Threatening. So The Malignant Potential Of CNS Tumors Is Of Two Patterns, Anatomic And Biologic. The Former Includes Deeply Seated Lesions That Could Not Be Reached By The Surgeon, And So May Progress Until Become Fatal, While The Latter Includes Aggressive Tumors That Grow Rapidly With The Resulting Neuropil Invasion And Destruction. Nevertheless CNS Cancers Do Not Fit Exactly The General Definition Of Malignancy As They Rarely Spread Outside Their Primary Location, Despite The Fact That Some Tumors Tend To Seed The Neuraxis Via CSF44. Space Occupying Primary Neoplasms Of The CNS And Its Covering Account For About 9% Of All Primary Neoplasms Of The Human Body And Metastatic Tumors Constitute About 5% 75. Among The Intracranial Space Occupying Tumors Those Of The Central Neurogenic Origin Claim Priority In Number And Complexity. These Are The Tumors Derived From Parenchymatous Neuroepithelial Elements Of The CNS Excluding Microglia; And They Are Widely Credited To Account For 40-50% Of All Intracranial Space Occupying Tumors62 Systematic Study Of Tumors Of The CNS Began When Bailey And Cushing Started Their Studies In The Early 1920’s. Over The Past Three Decades, Many Reports Suggested That Both Incidence And Pattern Of Intracranial Neoplasia Are Subject To Considerable Geographic And Racial Variations. Population Based Cancer Registries Are Established For A Better Understanding Of The Epidemiology . Knowledge Of The Regional Peculiarities Of These Lesions May Therefore Help In Identification Of Possible Risk Factors. Delay In Reporting Are A Reality And A Known Issue Influencing Registry Completeness For Achieving Data Quality Goals. Ultimately It Will Affect The Magnitude Of Rate Calculation Leading On To Cancer Rate Underestimation, That Will Hinder The Planning Measures For Updated Facility Treatment Centers. Hence It Is Essential That Quality Control Editing Of The Data With Incorporation Of Updates To The Cancer Registration Has To Be Refined Every Year. Primary Brain Tumors Continue To Be Among The Top Ten Causes Of Cancer Related Deaths In The World. As Per The CBTRUS( Central Brain Tumor Registry Of The United States), The Annual Incidence Of The Tumors Of The CNS Is 3.9 Per 100,000 Persons For Intracranial Tumors. Global Differences In Rates Tend To Correspond To The Level Of Economic Development, With The Highest Rates In North America, Australia, And Western Europe And The Lowest Rates In Asia, South And Central America. Regional Differences In Incidence Rates Of CNS Tumors Were Also Noted In India. According To The Data Obtained From Various Cancer Registries In India The Age Specific ,World Adjusted Incidence Rate Accounts To Be 5.1 Per 100,000 Persons. The Highest Incidence Of Brain Tumors Was Reported From Sikkim And Lowest In Mizoram State.75 Risk Factors Causing Brain Tumors Remain Uncertain. Racial Differences, Exposure To Radiation, Chemical Exposure In Working In The Rubber, Petrochemical Or Metal Industries And Family History Of Brain Cancer Are Postulated To Increase The Risk Of Brain Tumors. Excessive Use Of Mobile Phones Resulting In Exposure To Electromagnetic Waves Has Triggered A Great Inquisition Among Researchers To Label It As A Cause For Brain Tumors, But Its Etiopathogenesis Is Still Not Proven. So Epidemiological Studies Of Brain Tumors In Depth Is Necessary To Understand The Etiology Of Risk Factors. An Estimated 2400 Children Between The Ages Of 0-19 Years Are Diagnosed With Invasive Primary CNS Tumors In The United States Each Year109. The Incidence Of CNS Tumors In Children < 20 Years Is 4.58 Per 100,000 Person Years. (CBTRUS Report 2009). Brain Tumors Are Second Only In Frequency To Acute Lymphoblastic Leukemia In Children. Pilocytic Astrocytomas, Malignant Glioma And Medulloblastoma Are The Commonest Tumors. The Incidence Of CNS Tumors In Children Was Found To Have Increased In The Recent Years. This Incidence Has Been Mainly Attributed To The Introduction Of Magnetic Resonance Imaging (MRI) In The 1980s That Improved The Detection Of Low Grade Tumors Previously Unidentifiable By Other Less Optimal Imaging Modalities. A Comparison Using International Studies Of Primary Intracranial Tumors Results In An Average Male To Female Ratio Of 1.4:1 Across Geographical Areas. However Sex Ratios Varies Considerably By Histological Types. Gliomas Are Higher In Males And Females Show A Predominance With Meningiomas.1 The CNS Tumors Have Always Been A Cause Of Concern To The Pathologist Due To The Wide Variety In Their Appearances. Diagnosing A CNS Tumor Posses A Significant Challenge But The Gold Standard Used For The Definitive Diagnosis Of CNS Tumors Is The Microscopic Examination Of The Tumor The WHO 2007 Classification Is The Latest Updated System That Has Been Edited By Two Neuropathologists ( Dr. Louis And Dr. Weistler) And Two Molecular Pathologists ( Dr.Ohgaki And Dr.Cavenee), Reflecting The Gradual Shift In Modern Pathology. About 86 Major Types Of CNS Tumors And Their Variants Have Been Listed.52 Grading Is Fundamental For Optimal Prognostication And Deciding On The Choice Of Therapy. Histological Grading Of CNS Tumors Can Be Challenging Despite Criteria Given By WHO More Often Due To Limited Tumor Material Provided. The Number Of Mitosis Is Of Paramount Importance But Can Be Hard To Identify In The Haematoxylin And Eosin Stained Sections. Since Proliferative Activity Is A Reliable Method To Assess Tumor Biology Estimation Of Proliferative Activity Has Gained Much Enthusiasm And There Has Been Continuous Research To Employ Biological Markers Such As Ki -67 As An Adjunct To Conventional Morphological Variables. The Diagnostic Tools In The Investigation Of Brain Tumors Are Expanding Greatly With Advances In Imaging Studies. These Modalities Are Complementary To The Diagnosis And Are Not Confirmatory. Immunohistochemistry Is An Essential Clinical Research Tool In Medical Science In This Era. It Helps In Making Specific Confirmatory Diagnosis By Detecting Lesion Specific Markers. It Also Helps In Predicting The Final Outcome Of Neoplastic Lesion By Detecting Various Prognostic Markers Ki -67 Is A Novel Non Histone Nuclear Protein That Is Expressed In The Active Phases Of The Cell Cycle And Thus Labelling With The Monoclonal Antibody Against This Antigen Readily Identifies Cells That Are Actively Proliferating. Ki-67 Labelling Correlated Well And Yielded Credible Results In Our Study. However This Marker Should Not Be Used Alone But In Combination With Established Histopathological Criteria Of Malignancy.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Histopathological Analysis ; Ki 67 Expression in Various Central ; Nervous System Tumors.
Subjects: MEDICAL > Pathology
Depositing User: Subramani R
Date Deposited: 29 Jun 2017 01:50
Last Modified: 29 Jun 2017 01:50
URI: http://repository-tnmgrmu.ac.in/id/eprint/547

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