introduction to general pathology II 2013.pptx

7/28/2019 introduction to general pathology II 2013.pptx

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It is the Scientific study of disease" ."scientific study of the molecular, cellular, tissue, or

organ system response to injurious agents."

Definition of pathology

Pathology serves as a "bridge" or "link" between the

preclinical sciences (anatomy, physiology, etc.)

and the courses in clinical medicine.


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General Pathology

Common changes in all tissues. e.g.. Inflammation,

cancer, ageing, edema, hemorrhage .etc.

Systemic Pathology

Discussing the pathologic mechanisms in relation to

various organ systems e.g. CVS, CNS, GIT..etc.

Learning Pathology:


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Pathology focuses on 4 aspects of disease:

ETIOLOGY: Cause of disease.

PATHOGENESIS:

Mechanisms of development of disease.

MORPHOLOGY:

The structural alterations induced in cell and tissues.

FUNCTIONAL CONSEQUENCES:

Functional results of the morphologic changes, as

observed clinically.


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Biopsy: Removal andexamination of tissue obtainedfrom the living body


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pathogenesis

The sequence events in the response of the cells or

tissues to the etiologic agent, from the time it is initiated

to its final conclusion in recovery or death


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Clinical Symptoms & Signs

Clinical signs are seen only in the living individual.

Functional evidence of disease which can be

determined objectively or by the observer" (fever,

tenderness, increased respiratory rate, etc. )

Clinical symptoms are the patients complain

usually by its own words.


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Tumors based on

* cell of origin * biologic behavior

Benign

Epithelial Mesenchymal

Malignant

Epithelial Mesenchymal


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Differences between benign and malignant tumors

Feature Benign Malignant

Capsulat ion Usually present Usually absent

Mode of g rowth By expansion By infiltration

Differentiation Well differentiated Variable

Anaplasia Absent Present

Rate of gro wth Slow Rapid

Metastases Does not happen May occur

Recurrence Usually do not recur Common

Fate Cured by excision Usually fatal


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Differentiation and Anaplasia

Benign tumorsWell differentiated

Malignant tumorsRange from well to poorly differentiated

Hallmarks of anaplasia :Cells and nuclei show pleomorphismCells contain abundant DNA, coarse, clumped chromatinLarge NC ratio (1:1) rather than (1:4)Large nucleoliLarge of mitosis

DysplasiaPrecancerous condition in epithelial tissue

Anaplastic cells in epithelium

Dysplasia does not always progress to cancer


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Rate of Growth

Benign tumors

Generally grow slowly over a period of yearsMalignant tumors

Grow rapidly at an erratic pace


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Local Invasion

Benign tumorsgrow as cohesive, expanding masses that remain

localized to site of originDo not have capacity to metastasize to distant sitesFrequently are surrounded by a fibrous cap

Malignant tumors

Grow with progressive infiltration, invasion anddestruction of host tissuePoorly demarcated from surrounding normal tissue


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Benign

Malignant

Metastasi s


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Metastasis

Tumor implants that are discontinuous from theprimary tumors

30% of newly diagnosed patients with solidtumors present with metastasesHow do cancers spread?

Direct seeding of body cavities or surfacesLymphatic spread (carcinomas)Hematogenous spread (sarcomas)


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Benign tumors

In general, benign tumors are designated byattaching the suffix -oma to the cell of origin.Tumors of mesenchymal cells generally follow thisrule.

fibroblastic cells fibroma, cartilaginous tumor chondroma, tumor of osteoblasts osteoma

Nomenclature of benign epithelial tumors is more

complex. They are variously classified, based on:their cells of originmicroscopic architecturemacroscopic patterns.


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Thank you

introduction to general pathology II 2013.pptx

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