A Study on the Occurrence and Subtyping of Acute Leukemias Based on Morphology and Cytochemistry.

Sintha, M (2008) A Study on the Occurrence and Subtyping of Acute Leukemias Based on Morphology and Cytochemistry. Masters thesis, Madurai Medical College.

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Abstract

Leukemia Is The Term Used For Haematopoietic Neoplasm, Presenting With Wide Spread Involvement Of Bone Marrow And Peripheral Blood By Blasts And Is The Most Common Cancerous Disorder In Children1. Virchow Recognized Leukemia As A Distinct Disease In 1845 When He Used The Term Weisses Blut To Describe The Findings In An Autopsy In Which The Ratio Of Red Corpuscles To “Colorless (In Mass White)” Was Reversed2. He Used The Term Leukemia For The First Time In 1847 And Subsequently, Described Lymphatic And Splenic Forms3. Friedreich Recognized Acute And Chronic Types In 1857. Neumann, In 1868, Identified The Bone Marrow As The Origin Of Leukemia And Used Myelogenous As A Provisional Term That Has Been Validated Over Time. The First Case Of Acute Myeloid Leukemia (AML) Was Originally Termed Acute Non Lymphocytic Leukemia In 1900. During The First Half Of The Century Most Of The Subcategories Of Myeloid Leukemia Were Identified By Light Microscopy With The Aid Of Cytohistochemical Stains And Were Described Based On The Resemblance To Normal Hematopoietic Precursors. The Recognition Of The Philadelphia Chromosome In Chronic Myeloid Leukemia (CML) By Norwell And Hungerford In 1960 Was The First Demonstration Of Recurring Chromosomal Abnormality In Leukemia. In 1976 FAB Classification Was Proposed, With Several Subsequent Modifications. The FAB Group Defines Seven Subsets Of AML. Four Based On The Percentage Of Maturing Cells And Three Based On Lineage.FAB Classifies Acute Lymphoblastic Leukemia (ALL) Into Three Types Based On Morphology As L1, L2, And L3. In The Latter Half Of The Last Century, Numerous Cytogenetic Abnormalities, Including Specific Translocations, Were Identified In Subtypes Of AML And Led To Changes In Classifications, As Proposed In 1997 By The WHO4. Cytogenetics Has Profound Effect On Prognosis And Treatment. The WHO Subdivides AML Into True Denovo AML Occurring Predominantly In Young To Middle-Aged Adults, With Recurring Cytogenetic Translocations Or Inversions And MDS Related AML Occurring In Elderly Adults Often With Complex Chromosomal Abnormalities The WHO Recognizes Therapy Related AML And Retains The Morphologic Subcategories Of The FAB In Cases Not Otherwise Classified. The Category Of Acute Leukemia Of Ambiguous Lineage Is Also Added. As Per WHO Classification (2001) The Alls Are Separated Under Three Broader Categories, Precursor T-Cell, Precursor B-Cell, And Mature B-Cell Neoplasm Based On Their Immunophenotype5. The High Cost Of Cytogenetics And Immunophenotypic Studies Stands In Way Of Routine Application In All Patients. Inspite Of Advances Made In Classification And Prognostic Factor Delineation, It Is Essential To Classify Leukemias Basically Into AML And ALL As They Differ Significantly In Management And Prognosis. This Can Very Well Be Done By Combination Of Morphology And Cytochemistry Which Has A Sensitivity Of More Than 92%6. In A Developing Country Like India All The Patients Do Not Have Accessibility To Cytogenetics And Immunophenotypic Studies. Hence Classification Was Hitherto Done By Morphology Alone In The Past Decades. This Situation Necessitated The Introduction Of Cytochemistry, Which Is An Improvement Over The Previous Method, Though Not Up To The Level Of Precision Obtained In Cytogenetic Studies. Hence The Present Study Has Been Taken Up To Subtype Leukemias Using Morphology And Cytochemistry.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Occurrence and Subtyping ; Acute Leukemias; Morphology; Cytochemistry.
Subjects: MEDICAL > Pathology
Depositing User: Subramani R
Date Deposited: 27 Jun 2017 11:19
Last Modified: 27 Jun 2017 11:19
URI: http://repository-tnmgrmu.ac.in/id/eprint/457

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