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GENERAL PATHOLOGY

John White M.D. Pathologist/Department Chairman

What is pathology? …Why should you study pathology?

Pathology is the study of diseases. The word pathology came from the Latin words “patho” & “logy”. ‘Patho’ means disease and ‘logy’ means study, therefore pathology is a scientific study of disease.

Core Aspects of Diseases in Pathology

1. Etiology

2. Pathogenesis

3. Morphologic changes

4. Functional derangements and clinical

significance

Pathogenesis

Pathogenesis means the mechanism through which

the cause operates to produce the pathological and

clinical manifestations.

Morphologic changes

The morphologic changes refer to the structural

alterations in cells or tissues that occur following

the pathogenetic mechanisms. Those changes that can be seen with the naked eye are called gross morphologic changes & those that are seen under the microscope are called microscopic features.

Diagnostic Techniques in Pathology Histopathology Cytopathology Hematopathology Immunohistochemistry Microbiological examination Biochemical examination Cytogenetics Molecular techniques Autopsy

Histopathological Techniques

• Histopathological examination studies tissues under the microscope.
• Tissues for histopathological examination are obtained by biopsy.
• Biopsy is a tissue sample from a living person to identify the disease. Biopsy can be either incisional or excisional.
• Once the tissue is removed from the patient, it has to be immediately fixed by putting it into adequate amount of 10% Formaldehyde before sending it to the pathologist.

Cytopathologic techniques Cytopathology is the study of cells from various body sites to determine the cause or nature of disease. Applications of cytopathology:

1. Screening for the early detection of asymptomatic cancer
2. Diagnosis of symptomatic cancer
3. Surveillance of patients treated for cancer

Advantages of Cytologic Examination Compared to histopathologic technique it is cheap, takes less time and needs no anesthesia to take specimens.

Cytopathology methods

1. Fine-needle aspiration cytology (FNAC) In FNAC, cells are obtained by aspirating the diseased organ using a very thin needle under negative pressure. Virtually any organ or tissue can be sampled by fine-needle aspiration e.g. thyroid, breast, lymph nodes, skin and soft tissues. Deep organs, such as the lung, mediastinum, liver, pancreas, kidney, adrenal gland, and retroperitoneum are aspirated with guidance by fluoroscopy, ultrasound or CT scan.

Hematological examination This is a method by which abnormalities of the cells of the blood and their precursors in the bone marrow are investigated to diagnose the different kinds of anemia & leukemia.

Immunohistochemistry This is a method is used to detect a specific antigen in the tissue in order to identify the type of disease.