Pathological Terminology

Introduction

The word ‘Pathology’ is derived from two Greek words—pathos meaning suffering, and logos meaning study. Pathology is, thus, scientific study of structure and function of body in disease or in other words, pathology consists of abnormalities that occur in normal anatomy (including histology) and physiology owing to disease.

Terminology

Pathophysiology

‘Pathophysiology’ comprised by two words : patho=suffering; physiology=study of normal function. It includes study of disordered function
or breakdown of homeostasis in diseases.

Health

Health may be defined as a condition when individual is in complete accord with the surroundings,

Disease

A disease is loss of ease (or comfort) to the body (i.e. dis-ease). However, it must be borne in mind that in
health there is wide range of ‘normality’ e.g. in height, weight, blood and tissue chemical composition etc.

Patient

Patient is the person affected by disease.

Lesions

Lesions are characteristic changes in tissues and cells produced by disease in an individual or experimental
animal.

Pathologic changes or morphology

Pathologic changes or morphology consist of examination of diseased tissues.

Pathologic changes

Pathologic changes can be recognised with naked eye (gross or macroscopic changes) or studied by microscopic examination of tissues.

Etiology

Causal factors responsible for the lesions are included
in etiology of disease (i.e. ‘why’ of disease).

Pathogenesis

Mechanism by which the lesions are produced is termed pathogenesis of disease (i.e. ‘how’ of disease).

Symptoms

Functional implications of the lesion felt by the patient are symptoms and those discovered by clinician are physical signs.

Diagnosis

what is wrong

Prognosis

what is going to happen

Treatment

what can be done about it

Prevention

what should be done to avoid complications

Techniques for the Study of Pathology

AUTOPSY PATHOLOGY

Professor William Boyd in his unlimitable style wrote ‘Pathology had its beginning on autopsy table’. r, G.B. Morgagni in Italy (1682- 1771) and T.H.A Laennec (1781-1826) in France started collecting case records of hospital cases and began correlation of clinical features with lesions observed at autopsy a thus marked beginning of clinicopathologic correlation (CPC). CPC continues to be most important form of clinical teaching activity in medical institutions worldwide.

Traditionally, there are two method for carrying out autopsy, either of which may be followed:

Block extraction of abdominal and thoracic organs.
In situ organ-by-organ dissection.

SURGICAL PATHOLOGY

The term surgical pathology is currently applied synonymously with the histopathology, anatomic pathology ,morbid anatomy, and cellular pathology. Surgical pathology is classic and time-tested method of tissue diagnosis made on gross and microscopic study of tissues.

SPECIAL STAINS (HISTOCHEMISTRY)

H & E staining is routinely used to diagnose microscopically. The staining depends upon either physical or chemical or differential solubility of the stain with the tissues.

ENZYME HISTOCHEMISTRY

Enzyme histochemical techniques require fresh tissues for cryostat section and cannot be applied to paraffin-embedded sections or formalin-fixed tissues since enzymes are damaged rapidly.

Currently, enzyme histochemistry has limited diagnostic applications and not so popular, partly due to requirement of fresh tissues and complex technique, and partly due to relative lack of specificity of reaction in many cases, and hence have been largely superseded by immunohistochemical procedures and molecular pathology techniques.

BASIC MICROSCOPY

Microscope is the basic tool of pathologist just as is stethoscope for the physician and speculum for gynecologists’. It’s an instrument which produces greatly enlarged images of minute objects.

TYPES OF EM

1. Transmission electron microscope (TEM).

2. Scanning electron microscope (SEM).

IMMUNOHISTOCHEMISTRY

Immunohistochemistry (IHC) is the application of immunologic techniques to the cellular pathology. The technique is used to detect status and localisation of particular antigen in cells (membrane, cytoplasm or nucleus) by use of specific antibodies which are then visualised by chromogen as brown colour.

FLOW CYTOMETRY

Flow cytometry is a modern tool used for the study of properties of cells suspended in a single moving stream. Flow cytometry, thus, overcomes the problem of subjectivity involved in microscopic examination of cells and tissues in histopathology and cytopathology.

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