Chapther_5_Neoplasia[1]

Chapther_5_Neoplasia[1] - Chapther 5 Intro Neoplasia...

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Chapther 5 Neoplasia Intro - Neoplasm – neo (new) plasm (thing formed) o Autonomous growth of tissue o Abnormal cell proliferation o May be different from precursor - Solid Neoplasm (tumors) o Localized-benign o Spreading-malignant/cancer (metastisis – spreading) Cancer - ancient disease - incidence increases with age - longer life = increase population at risk - increase cancer rate is related to increase in population age Generalities - irreversible, autonomous growth - derived from cells that usually proliferate - degree of differentiation will vary - initiating stimulus often unknown - Arises from mutation in growth, apoptosis and repair genes. Benign vs. Malignant - Benign: o non invasive o Do not metastasize to distant sites o More differentiation o Usually spare host (except critical locations) Exceptions: Neuroendocrine/heart valve tumors and brain tumors - Malignant o Invasive o Able to metastasize to distant sites Blood and lymphatic system o Range of differentiation o Usually kill host Exception : surgical removal/cure Some connective and breast tumors - Some tumors are difficult to classify o Basal cell carcinoma Histologically malignant
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Rarely metastasizes o Pleomorphic ademona Benign! Classification - Benign and malignant are both described by tissue origin - “oma” implies benign, preceded by tissue of origin o Chondroma – cells resemble chondrocytes o Lipoma – fatty tumor o Fibroma – fibrous tissue o Chondroblastoma – tumor resembles precursor of chondrocytes (blast – immature cell type) Malignant Tumors - similar to benign but suffix is “carcinoma” o carcinoma – epithelial origin o sarcoma – mesenchymal origin Eg malignant tumor of the stomach – gastric adenocarcinoma Squamous cell carcinoma – invasive skin tumor Chondrosarcoma, fibrosarcoma Malignant Tumors - Name suggests tissue of origin Osteogenic sarcoma – bone Bronchogenic carcinoma – lungs o Exceptions in nomenclature (all malignant) Hepatoma Melanoma Seminoma Lymphoma o Blood Tumors Leukemia - malignant proliferation of leukocytes Secondary Descriptors - Papillary – frondlike (leaf-like) structure - Medullary – soft cellular tissue, little connective tissue - Scirrhous/desmoplastic – dense fibrous stroma - Colloid carcinomas – secrete abundant mucous - Comadecarcinoma – necrotic material that can be expressed (intraductal) - Tumors with poor histogenesis are given eponyms o Hodgkins disease, Ewing sarcoma Histologic Diagnosis of Malignancy - no reliable molecular indicators - based on microscopy
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- judgment call (in some cases) Benign Tumors - tend to be similar to parent tissue - not able to invade - may be encapsulated with connective tissue or non-encapsulated Malignant Tumors - Histologic features o Anaplasia or cellular atypia o Mitotic activity o Growth patterns o Invasion o Metastasis - Histologic features o Anaplasia or cellular atypia Lack of differentiation Correlates with tumar aggressiveness
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This note was uploaded on 04/07/2008 for the course PHS 3510 taught by Professor Hardej during the Spring '08 term at St. Johns Duplicate.

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Chapther_5_Neoplasia[1] - Chapther 5 Intro Neoplasia...

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