this slideshare gives an overview of pathology.

1. Introduction to pathology
Dr. Biniam Tsegaye (MD)
Pathologist
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2. Introducing the department
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3. • Office No.13, ground
• 4 pathologist (1 Abroad for
study)
• Biniam Tsegaye
• Hadas W/zgina
• Sara Kiros
• Melisachew Mulatu
• 3 residents
• 2 GP’s
• 8 histotechnologist
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4. PATHOLOGY
• Pathos (suffering)
• Logos (study)
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5. • Scientific study of diseases
• Scientific study of structural and functional changes of cells, tissues and
organs that underlie diseases
• A bridging discipline that connects basic sciences with clinical medicine
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6. Tree of medicine
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7. General
• Cell injury, adaptation & cell death
• Inflammation
• Tissue repair
• Hemodynamic disorders
• Immunopathology neoplasia
• Genetic & pediatric disease
• Environmental & nutritional disease
• Infectious disease
Systemic
• Ds of blood vessels
• Ds of Heart
• Ds Hematopoietic & lymphoid
• Ds of Respiratory
• Ds of Kidney & its collecting system
• The Oral cavity & GI tract
• The Liver, GB & biliary tract
• The Pancreas
• The Male genital system
• The Female genital system & Breast
• The Endocrine system
• The Musculoskeletal system
• The Skin
• The Nervous system
•Traditionally classified in two
1. General pathology
2. Systemic pathology
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8. History
Hippocrates(460–370? BC)
Cornelius Celsus (about 30BC–38 AD).
- He wrote De Re Medicina in eight
volumes.
- Book III contains the classic definition of
inflammation:
“Notae vero inflammationis sunt
quatuor, rubor et tumor, cum calore et
dolore”
Galen (129– 201 AD) - he is by many considered as the greatest medical
figure of that time.
- „Crab-like‟ growth of cancer John Hunter (1728–1793) was not just one of
them; he was an extraordinary one.
- He also was author of “Venereal Disease”
(1786) and of “Treatise on the Blood,
Inflammation and Gunshot Wounds”
Batista Morgagni (1682–1771) modern
medicine and pathology.
- It became generally accepted that
diseases were organ based
Thomas Hodgkin (1798–1866)
Rudolph L.K. Virchow (1821–1902)-
father of pathology
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9. What is a Disease?
• A disease is a physical or functional disorder of normal body systems that places an
individual at increased risk of adverse consequences
• Diseases are diagnosed by physicians or other health care providers through a
combination of tools
• When a disease is diagnosed, treatment is given to prevent or ameliorate
complications and to improve prognosis
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10. The core aspects of diseases in pathology
• Pathology gives explanations of a disease by studying the following four aspects of
the disease
1. Etiology
2. Pathogenesis
3. Morphologic changes
4. Functional derangements and clinical significance
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11. Etiology
• Cause of disease
• Primary Vs. Secondary (idiopathic)
• Understanding of the etiology is important for
– Disease diagnosis
– Disease treatment
– Prediction of prognosis
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12. • There are two major classes of etiologic factors:
1. Genetic /intrinsic
2. Acquired
– Infectious, nutritional, chemical, physical, hypersensitivity reactions
Genetic + Acquired
(multifactorial)
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13. Pathogenesis
• Mechanism of disease development
• Sequence of events starting from initial stimulus(etiology) to final disease expression
• Pathogenesis leads to morphologic changes
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14. Morphologic changes
• The morphologic changes refer to the structural alterations in cells or tissues that occur
following the pathogenetic mechanisms
• The structural changes in the organ can be seen with the naked eye or they may only be seen under
the microscope. 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 changes
• Both the gross & the microscopic morphologic changes may only be seen in that disease, i.e. they
may be specific to that disease…
• Therefore, such morphologic changes can be used by the pathologist to identify (i.e. to diagnose)
the disease.
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19. Clinical significance
• Functional consequences and functional derangements as a result of
morphologic changes
• The morphologic changes in the organ influence the normal function of
the organ
• By doing so, they determine the clinical features (symptoms and signs),
course, and prognosis of the disease
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Lung,
pneumonia
Liver,
metastasis
What could be
the
manifestations?

21. Try this
TUBERCULOSIS HIV/AIDS
- Etiology
- Pathogenesis
- Morphologic changes
- Clinical significance
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22. Diagnostic techniques used in pathology
• The pathologist uses the following techniques to diagnose diseases:
1. Cytopathology
2. Histopathology
3. Hematopathology
4. Immunohistochemistry
5. Microbiological examination
6. Biochemical examination
7. Cytogenetics
8. Molecular techniques
9. Autopsy
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23. Cytopathological techniques
• Cytopathology is the study of cells from various body sites to determine the cause or nature of
disease
• Advantages of cytologic examination
Compared to histopathological technique is
1. Cheap
2. Takes less time
3. Needs no anesthesia to take specimens
4. It is complementary to histopathological examination.
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24. Applications of Cytopathology:
• The main applications of cytology include the following:
1. Screening for the early detection of asymptomatic cancer
• The examination of scrapings from cervix for early detection and prevention of cervical cancer.
2. Diagnosis of symptomatic cancer
• Cytopathology may be used alone or in conjunction with other modalities to diagnose tumors
revealed by physical or radiological examinations.
3. Surveillance of patients treated for cancer
• For some types of cancers, cytology is the most feasible method of surveillance to detect recurrence.
The best example is periodic urine cytology to monitor the recurrence of cancer of the urinary tract.
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26. Cytopathology methods
• There are different cytopathologic methods including:
1. Fine-needle aspiration cytology (FNAC)
2. Exfoliative cytology
3. Abrasive cytology
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27. 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.
• The aspirated cells are then stained & are studied under the microscope.
• Superficial organs (e.g. thyroid, breast, lymph nodes, skin and soft tissues) can be easily
aspirated.
• Deep organs, such as the lung, mediastinum, liver, pancreas, kidney, adrenal gland, and
retroperitoneum are aspirated with guidance by fluoroscopy, ultrasound or CT scan.
• FNAC is cheap, fast, & accurate in diagnosing many diseases.
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28. Diffuse goiter
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29. Procedure
• Informed consent
• Take important history
• Proper positioning of patient
• Exact location of lesion
• Select FNAC technique
• Take sample
• Smear preparation
• Assess sample adequacy….. on site evaluation
• Fixation
– Air drying
– Alcohol fixation
• Staining
– Romanowsky staining
– Pap staining
• Microscopy
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30. FNAC
• Informed consent
• Nature of procedure
• Purpose
• Risk and complication
• Benefits
• Alternatives
• Tell patient about
– Pain during and after procedure w/c usually does not need analgesic
– Bleeding…rarely
– Injury to nearest organs
– Possibility of repeat FNA
– Possibility of Biopsy
– FNA is not therapeutic
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32. Patient sent with the diagnosis of lymphoma,
but FNAC reveals inflamed salivary gland
Exact location
Size, consistency, single/multiple,
relation to nearby structures
Insert needle, Create negative
pressure, Number of passes, and Cut
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33. Palpate….location
size, consistency, relation to other structures
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34. Patient positioning….thyroid
Supine position with extended neck
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38. FNAC clinic
• Examination coach
• Good air conditioning
• Good light
• Microscope
• Sink…with appropriate water supply and drainage system
• Instrument trolley
• Examination tray for instruments
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40. FNAC clinic materials
• Syringe
• Syringe holder???
• Needles of various caliber
• Gloves….disposable and surgical
• Alcohol, iodine—antiseptics
• Cotton, gauze……swab
• Slides…frosted and non frosted
• Pencil…..labeling
• Protective mask and Apron
• Anesthetic drugs…2% lidocaine w/out adrenaline
• Safety box
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41. Image guided….
• CT guided FNA…high diagnostic accuracy and less complication
• U/S guided FNA….Non palpable, multiple, small lesions of thyroid,
breast and also intraabdominal masses
• Endoscopy guided ultrasound FNAC (EUS-FNAC)…mediastinum, bile
duct, hypopharynx, rectum, duodenum, pancreas…..
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43. Air drying fixation
• Immediate fixation is mandatory
• Put the smear in open air for about 5min
• Followed by Romanowsky stain
• If not well fixed (not dry well)….thick smear, less time
– Air drying artifact….microscope (enlarged nuclei with fuzzy cell boundaries)
– False positive or false negative results
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44. Air dried smear with MGG stain, Small cell carcinoma of lung
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45. Alcohol fixation
• Wet fixation
• Spray fixative or dipping the slide in 95% ethyl alcohol
• Then followed by Pap staining
• Immediate fixation is crucial
• Delayed fixation….cellular distortion and poor preservation of nuclear detail
• Choice of fixative depends upon the local policy of the laboratory.
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46. Alcohol fixation…..Pap staining, Small cell carcinoma of lung
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47. Stains
• Papanicolaou stain
–Dr. George papanicolaou----father of cytopathology
–Pap stain in alcohol fixed slides
–Shows nuclear details very well
–Uses standard nuclear staining (Hematoxylin)
–Two counterstains of cytoplasm…OG-6, EA
–Outcome of this stain…crisp nuclear detail and transparency
of the cytoplasm
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48. Pap staining of cervical epithelium
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49. Romanowsky stains
• Important in air dried slides
• Are mixtures of eosin and methylene blue
• Show cytoplasmic details and cell outline better than Pap
• Show extracellular materials better
• Are metachromatic, unlike Pap
1. Wright’s stain
2. Giemsa stain
3. Wright’s Giemsa stain
4. May Grunwald Giemsa stain /MGG stain
5. Diff Quick stain…..for rapid staining and assessing adequacy of material
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50. Diff Quick stain
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51. NHL Pap stain
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52. MGG stain of the above NHL case
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53. Metastatic clear cell carcinoma of kidney
a. Pap stain
b. MGG stain
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54. Stromal component is best identified using Romanowsky stain
Epimyoepithelial carcinoma of the parotid
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55. Special stains
• Periodic acid Schiff…PAS….Glycogen
• PAS distase (PAS-d) and Alcian blue…..mucins
• Methenamine silver (Grocott)……detection of fungi
• Ziehl Nielsen stain….AFB
• Perls stain….detection of hemosiderin
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57. Ascitic fluid…malignant
positive for PAS-d stain… adenocarcinoma
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59. 2. Exfoliative cytology
• Refers to the examination of cells that are shed spontaneously into body
fluids or secretions.
Sputum
Cerebrospinal fluid
Urine
Effusions in body cavities ( pleura, pericardium, peritoneum )
Nipple discharge
Vaginal discharge
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60. Ascitic fluid……40/M
sheets of lymphocytes
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61. Ascitic fluid…..50/F
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62. Pleural fluid…..45/M
sheets of neutrophils
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63. Pleural fluid…..50/M
Sheets of eosinophils
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64. 3. Abrasive cytology
• Cells are dislodged by various tools from body surfaces (skin, mucous membranes,
and serous membranes).
• Cells may be dislodged by
• Scraping
• Swabbing
• Endoscopic brushing of mucosal surfaces
• Washing (lavage of mucosal surfaces)
• E.g. preparation of cervical smears with small brush to detect cancer of the uterine
cervix at early stages.
• Such cervical smears, also called Pap smears
• Barr body test
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65. Pap staining of cervical epithelium
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66. Barr bodies represent the inactive X chromosome and
are normally found only in female somatic cells.
Barr Bodies
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67. A woman with the
chromosome
constitution 47, XXX
should have 2 Barr
bodies in each cell.
XXY individuals are
male, but have a
Barr body.
 XO individuals are
female but have no
Barr bodies.
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68. Dora Ratjen ,November 20, 1918 Bremen ,Germany - April 22,
2008) was a German athlete who competed for Germany in the
Women's High Jump at the 1936 Summer Olympics at Berlin ,
finishing fourth, but was later discovered to be male .
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69. Stella Walsh won a silver medal at the
1936 Olympics - but was later found to be a
man
Stella Walsh was killed in a random act
of violence in 1968. As part of a routine autopsy,
coroners discovered that Stella was a
masculine pseudohermaphrodite (mosaicism)
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70. 800m gold medal in Berli 2009
Semenya (south Africa) told to take
gender test
Reports in two newspapers in September said the results of the tests
showed Semenya has both male and female characteristics. The IAAF
has declined to confirm those reports.
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72. Histopathological techniques
• Studies tissues under the microscope
• The pathologist looks for abnormal structures in the tissue
• 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
fixedby putting it into adequate amount of 10% formaldehyde
(10% formalin) before sending it to the pathology laboratory.
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73. Steps in histopathological study
1. Excisional or incisional biopsy
2. Put specimen in 10% formalin
3. Macroscopic examination
 Specimen contains
 Measurement
 Cut surface
 Take tissue bits with size of 1*1.5cm and 2-3mm in thickness
 Tissue bits are put in plastic or steel cassettes
 Cassette labeling
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74. 5. Tissue processing
6. Embedding
7. Preparation of tissue block
8. Tissue is then sectioned- microtome machine
9. Tissue staining e.g. Hematoxylin/Eosin
10. Microscopic examination
11. Reporting
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83. Tissue processing
• Sequential step which involves
1. Fixation
2. Dehydration
3. Clearing
4. Infiltration
• Tissue processing enables tissues to be embedded in to
mediums such as wax and cut in to thin sections
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84. 84
Tissue
processor

85. After processing?
• Embedding- processed tissue will be embedded in paraffin/wax
• Cool the paraffin in the cooling plate
• Detach the embedding mold from the cassette
• Now the cassette contain tissue with paraffin- tissue block
• Sectioning using microtome machine
• Sectioned tissue is put in a water bath
• Sectioned tissue is transferred from water bath to slides
• Slides are put in the oven of embedding center
• Tissue staining
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86. Put the tissue in an embedding mold
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87. Apply melted wax over the mold
Put tissue over the wax
put a cassette over the tissue and wax
Apply melted wax over the cassette
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88. Put mold and cassette over a cooling plate
Detach the mold from the cassette
Cassette with tissue= tissue block
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89. Sectioning using microtome
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90. Transfer the section in to water bath
Then transfer the section in to a slide from the water bath
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91. Put the slide in the oven of the embedding center
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92. Slide staining
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Routine histology stain is
Hematoxyline and Eosin
abbreviated as H&E.

93. Histological stains
• Staining-identification of different tissue components by their
color reactions.
• Three types
1. Vital staining- staining of living tissue by injecting staining
solution in to the animal body i.e. research purpose
2. Routine staining- staining of various tissue components with
little differentiation except between nucleus and cytoplasm
3. Special staining-
 More limited
 Selective staining
 Demonstration of special features such as bacteria, fungi,
particular cell products, microscopic intercellular
structures.
 DNA staining- Feulgen stain 93

94. 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
• Peripheral blood smear or Bone marrow aspiration
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95. Plasma cell….eccentrically located nucleus and perinuclear halo
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96. Metamyelocyte…
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97. Bands
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98. Peripheral blood….neutrophils
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99. Bone marrow aspiration
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100. Peripheral blood…CML
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101. Bone marrow aspiration…MDS
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102. Peripheral blood
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103. Peripheral blood
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104. Immunohisto/ cytochemistry
• This is a method is used to detect a specific
antigen in the tissue /cells in order to identify the
type of disease.
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105. 105
C-MYC
MIB

106. Cervical lymph node FNA /34 M
HX of melanoma
DDX….????? melanoma
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107. Microbiological examination
• This is a method by which body fluids, excised
tissue, etc. are examined by microscopical, cultural
and serological techniques to identify micro-
organisms responsible for many diseases.
• AFB staining of pleural fluid…microscopy
• Culture…culture from LN
• Serology……HIV
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108. Biochemical examination
• This is a method by which the metabolic
disturbances of disease are investigated by assay
of various normal and abnormal compounds in the
blood, urine, etc.
• For example, in diabetes mellitus, biochemical
investigation provides the best means of diagnosis
and is of greatest value in the control of the
disease
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109. Clinical genetics (cytogenetics)
• This is a method in which inherited chromosomal
abnormalities in the germ cells or acquired
chromosomal abnormalities in somatic cells are
investigated using the techniques of molecular biology.
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110. Molecular techniques
• Different molecular techniques such as fluorescent in situ
hybridization, Southern blot, etc... can be used to detect
genetic diseases.
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111. Autopsy
• Autopsy is examination of the dead body to identify the cause
of death
• This can be for forensic or clinical purposes
1. Eliminate suspicion
2. Provide reassurance to families
3. Substitute facts for conjecture
4. Construct a better defense
5. Reduce the number of claims
6. Improve the quality of care
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112. What is a Disease?
• A disease is a physical or functional disorder of normal body systems
that places an individual at increased risk of adverse consequences
• Diseases are diagnosed by physicians or other health care providers
through a combination of tools
• When a disease is diagnosed, treatment is given to prevent or
ameliorate complications and to improve prognosis
112

113. The causes of disease
• Diseases can be caused by either
1. Environmental factors
2. Genetic factors
3. Combination of the two
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114. • Environmental causes of disease are many and are classified into:
1. Physical agents
2. Chemicals
3. Nutritional deficiencies & excesses
4. Infections & infestations
5. Immunological factors
Hypersensitivity reaction, Immunodeficiency,
Autoimmunity
6. Psychogenic factors
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115. Genetic Factors
• These are hereditary factors that are
inherited genetically from parents.
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116. Course of disease
• The course of a disease in the absence of any intervention is called the
natural history of the disease. The different stages in the natural history
of disease include:
 Exposure
 Latency period between exposure and biological onset of disease
 Biological onset of disease; this marks the initiation of the
disease process, however, without any sign or symptom.
Following biological onset of disease, it may remain asymptomatic or
subclinical (i.e. without any clinical manifestations), or may lead to overt
clinical disease.
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117.  Incubation (induction) period refers to
variable period of time without any obvious signs or
symptoms from the time of exposure.
 Clinical onset of the disease, when the signs
and
symptoms of the disease become apparent. The
expression
of the disease may be variable in severity or in
terms of
range of manifestations.
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118. Outcome and consequences of disease
• Following clinical onset, disease may follow any of the following trends:
1. Resolution can occur leaving no sequelae
2. The disease can settle down, but sequelae are left
3. It may result in death
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119. Clinical death
• Clinical death is the reversible transmission between life and biologic death.
• Clinical death is defined as the period of respiratory, circulatory and brain arrest
during which initiation of resuscitation can lead to recovery.
Signs indicating clinical death are
 patient is without pulse or blood pressure
 completely unresponsive to the most painful stimulus.
 Pupils are widely dilated
 Some reflex reactions to external stimulation are preserved. For example, during
intubations, respiration may be restored in response to stimulation of the receptors
of the superior laryngeal nerve, the nucleus of which is located in the medulla
oblongata near the respiratory center.
 Recovery can occur with resuscitation. 119

120. Biological death
• Biological death (sure sign of death), which sets in after
clinical death, is an irreversible state of cellular
destruction.
• It manifests with irreversible cessation of circulatory
and respiratory functions, or irreversible cessation of all
functions of the entire brain, including brain stem.
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121. Pathologist
• A person, MD study pathology
• What we do currently?
Cytopathology Biopsy AutopsyHematopathology
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122. THANK YOU
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