INTRODUCTION TO PATHOLOGYDr Mustafa Salah Fadhil MSc, FIBMS path
PATHOLOGYWhat is pathology?
Branches & divisions of pathology?
What is pathology dealing with?
What is bx?
Types of bx?
Indications of bx?
PATHOLOGYPathology: is the study of disease.
It is central to the whole practice of evidence-based medicine.Anyone who studies the mechanisms of a disease can be described as a pathologist
BUT; traditionally the term is restricted to those who have a involvement in providing a diagnostic service to a hospital or undertake research in a pathology department.
Subdivisions of pathology• Histopathology: the investigation and diagnosis of disease from the examination of tissues
• Cytopathology: the investigation and diagnosis of disease from the examination of isolated cells
• Morbid anatomy and forensic pathology: is concerned with medico-legal postmortem examinations.
• Microbiology: is the study of infectious diseases and their causes. This can be subdivided into bacteriology, virology, mycology (the study of fungi), and protozoology (the study of infections by protozoa).
• Haematology: is study of diseases of the blood.
Subdivisions of pathology• Chemical pathology or clinical biochemistry: is the study of body chemistry, usually by assaying the levels of substances – electrolytes, enzymes, lipids, trace elements – in the blood or urine or body fluids.
• Immunology: is the study of host defences against external threats and autoimmunity, when the body’s defence systems are turned on themselves
• Genetics: is the study of inheritance of characteristics and diseases, or a predisposition to diseases.
- Clinical geneticists, are directly involved with patients
- Laboratory-based geneticists apply the traditional techniques of karyotyping, polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH), gene- expression profiling, and DNA sequencing
LEARNING PATHOLOGYPathology is best learnt in two stages:
General pathology: the mechanisms and characteristics of the principal types of disease process (e.g. inflammation, tumors, degenerations)
Systematic pathology: the descriptions of specific diseases as they affect individual organs or organ systems (e.g. appendicitis, lung cancer, atheroma).
Techniques in pathology• Light microscopy
• Immunohistochemistry and immunofluorescence
• Electron microscopy
• Biochemical techniques
• Haematological techniques
• Cell cultures
• Medical microbiology
• Molecular pathology in situ hybridisation/ polymerase chain reaction/ DNA microarrays
PATHOLOGYBiopsy: Tissue taken from a living organism for the purpose of microscopic examination & laboratory analysis
The word biopsy is derived from Greek word
‘bios’ = life
‘opsis’ = vision
Indications of biopsyi. Cystic lesion: Biopsy is strongly recommended in case of cystic lesions no matter how confident the clinician is about the clinical diagnosis, the reason behind this is that various cysts have different prognosis and aggressive nature is also exhibited by some cysts which will change the treatment plan.
ii. Hard tissue lesions: Most of the bony lesions cannot be diagnosed exclusively based on their radiographic appearance. Biopsy is required for shortlisting final diagnosis out of provisional diagnosis.
iii. Oral mucosal lesions: Any lesion which show change in color, or show any kind of proliferative, ulcerative or abnormal growth.
iv. Persistent lesions: Lesions that persist for a longer time ( > 2weeks) even after the removal of irritating factor.
Indications of biopsyv. Premalignant state: Those lesions, in which malignant transformation is suspected, are strongly indicated for biopsy.
vi. Level of malignancy: Biopsy is used for defining the extent of a disease process is a neglected aspect of clinical pathology.
vii. Systemic illness: it is also indicated in those few systemic diseases like lupus, amyloidosis, scleroderma, or sjogren's syndrome that need a histological confirmative diagnosis.
viii. Infectious origin; Biopsy confirmation is required in few infectious diseases like syphilis, mucormycosis, TB…
Contraindications of biopsyTYPES OF BIOPSY
• Core needle biopsy
• Excisional biopsy
• Incisional biopsy
• Frozen section
Types of biopsy by endoscopy– Gastroscopy (esophagus-duodenum)
– Colonoscopy (terminal ileum-anus)
– Laryngoscopy (pharynx-larynx)
– Bronchoscopy (trachea-large bronchi)
– Superficial localization & body cavities
– Deep localization
– US guided bx or FNAC
– CT scan guided bx or
Brush biopsy - Lung -Cervix