WEEK 15-17

Histopathologic and Cytologic Techniques

  • Presented by: Clare Bautista

Outline

  • General Pathology

  • Histopathologic Techniques

  • Exfoliative Cytology

  • Principles of Autopsy and Biopsy

Histology vs Histopathology

  • Histology: Microscopic study of normal tissues.

  • Histopathology: Study of tissues affected by disease.

  • Techniques for preparation include histologic or histopathologic methods.

General Pathology

  • Pathology: Study of structural, biochemical, and functional changes in cells and tissues that underlie disease.

  • Origin: Pathos (suffering) + Logos (study).

Four Aspects of Pathology

  1. Etiology: Origin of the disease.

  2. Pathogenesis: Sequence of events following exposure to the injurious agent.

  3. Morphologic Changes: Structural alterations in tissues.

  4. Functional Derangements/Clinical Manifestations: Changes resulting in clinical signs and symptoms, including disease progress.

Inflammation

  • Total of changes in response to an injurious agent, focusing on protection of the body.

5 Cardinal Signs of Inflammation

  • Rubor: Redness due to increased blood flow.

  • Tumor: Swelling from increased permeability and edema.

  • Calor: Heat from increased blood content.

  • Dolor: Pain from pressure or nerve damage.

  • Functio Laesa: Loss of function.

Classification of Inflammation

  • By Duration: Acute (<2 weeks), Chronic (>2 weeks), Subchronic.

Acute Inflammation

  • Sudden onset, characterized by cardinal signs and predominance of PMNs (polymorphonuclear leukocytes).

Chronic Inflammation

  • Proliferative, longer duration, characterized by mononuclear cells (macrophages, lymphocytes).

Types of Exudate in Inflammation

  • Serous, Fibrinous, Catarrhal, Hemorrhagic, Suppurative/Purulent inflammation.

Abnormalities in Cell Growth

  • Retrogressive Changes: Tissues smaller than normal.

    • Examples include Aplasia, Agenesia, Hypoplasia, Atresia.

  • Progressive Changes: Tissues larger than normal. Includes Hyperplasia and Hypertrophy.

  • Degenerative Changes: Metaplasia, Dysplasia, Anaplasia, Neoplasia.

Microscopy and Tumor Differentiation

  • Tumors are divided into:

    • Parenchyma: Active cells.

    • Stroma: Connective tissue framework.

  • Cancer staging: TNM system (Tumor size, Node involvement, Metastasis).

Fixation Process in Histopathology

  • Fixation: First step to preserve cell/tissue integrity.

  • Types include Additive (e.g. Formalin) and Non-additive (e.g. Alcohol).

  • Factors affecting fixation: pH, temperature, thickness, osmolality.

Tissue Processing Steps

  1. Fixation

  2. Dehydration

  3. Clearing

  4. Infiltration

  5. Embedding

  6. Sectioning

  7. Staining

  8. Mounting

  9. Labeling

Exfoliative Cytology

  • Microscopic study of desquamated cells (e.g., Pap smear).

  • Specimens require immediate fixative application for optimal results.

Autopsy Evaluation

  • Process to investigate cause of death through tissue examination.

  • Various techniques: R. Virchow, C. Rokitansky, A. Ghon, M. Letulle.

Legislation in Medical Technology

  • Laws and their effectiveness dates include:

    • RA 1517: Blood Banking Law of 1956

    • RA 5527: Philippine Medical Technology Act of 1969

    • RA 9165: Comprehensive Dangerous Drugs Act of 2002

    • RA 11166: Philippine HIV and AIDS Policy Act of 2018

Conclusion

  • Understanding the essential techniques and processes in histopathology is vital for accurate diagnosis and treatment planning.