The Histopathology Section

Question 1

Histopathologic Techniques

Answer 1

involves different procedures that have been adopted for the preparation of materials and tissue for microscopic examination.

Question 2

12 steps in Histopathologic Techniques

Answer 2

Numbering, Fixation, Dehydration, Clearing, Wax impregnation, Embedding, Blocking, Trimming, Sectioning, Staining, Mounting, and Labelling

Question 3

Receptionist

Answer 3

• Validates if the specimen is adequate or good for tissue processing.
• 1st person that will receive the specimen and put it into the container

Question 4

Container: contain fixatives

Answer 4

• Proportional to the size of the specimen
  o Clear
  o Unbreakable
  o Wide mouthed bottle

Question 5

Container: contain fixatives

Answer 5

• Proportional to the size of the specimen
  o Clear
  o Unbreakable
  o Wide mouthed bottle

Question 6

Specimen source

Answer 6

1. Bilateral organs
   o Examples: Extremities, kidneys, lungs and ovaries)
2. Miscellaneous
   o Examples: age, sex, ward

Question 7

1. Numbering

Answer 7

Basic information needed:
1. Date and time
2. Name of the patient
3. Specimen Number
o C - Cytology specimen
o A - Anatomical specimen
o S - Surgical specimen
❖ Example: S-09-2111

Question 8

2. Fixation

Answer 8

Most critical step in histopathological techniques
- preservation of biological tissues

o Primary aim: preserve the morphology and chemical constituents of the tissue.

o Secondary aim: protect and harden the specimen for further handling.

Question 9

Effects on Fixatives

Answer 9

1. Inhibit bacterial growth and reduce the risk of infections
2. Act as mordant or accentuator accelerating the staining process.

Question 10

Type of Fixative

Answer 10

According to Actions
- Microanatomic Fixative
- Cytological Fixative
- Histochemical Fixative

According to Compositions
- Simple Fixative
- Compound Fixative

Question 11

Microanatomic Fixative

Answer 11

• Involves small tissue or organ
  o 10% Formol Saline
  o 10% Neutral Buffered Formalin

Question 12

Cytological Fixative

Answer 12

• Involves body fluid or secretion
  1. Nuclear Fixatives - Flemming’s Fluid, Bouin’s Fluid, Heidenhain’s Susa
  2. Cytoplasmic Fixatives Kelly’s Fluid, Orth’s Fluid

Question 13

Histochemical Fixative

Answer 13

• Involves tissue containing labile substances
  o 10% Formol Saline
  o Absolute Ethyl Alcohol
  o Acetone

Question 14

Simple Fixative

Answer 14

• Uses only one chemical for fixation
  1. Aldehydes - Formaldehyde, Glutaraldehyde
  2. Metallic Fixatives - Mercuric Chloride, Chromate Fixatives, Lead Fixatives

Question 15

Compound Fixative

Answer 15

• The use of two or more chemicals for fixation

Question 16

3. Dehydration

Answer 16

• Utilizing chemical known as dehydrating agents.
• Removing of intracellular and extracellular water and fixatives in the tissue

o Examples: Alcohol (most commonly used), Acetone, Dioxane, Tetrahydrofuran, Cellosolve (Ethylene glycol monoethyl ether)

Question 17

4. Clearing

Answer 17

• Removing of dehydrating agents.
• Xylene - most commonly used

Question 18

5. Impregnation

Answer 18

• Also known as infiltration.
• The process whereby the clearing agent is completely removed from the tissue and replace by a medium that will completely fill all the tissue cavities.

❖ Paraffin wax impregnation
o Paraffin: the simplest, most common and best
embedding medium used for routine tissue
processing.

Question 19

Paraffin wax impregnation

Answer 19

Paraffin: the simplest, most common and best
embedding medium used for routine tissue
processing.

Question 20

6. Embedding

Answer 20

• Also known as casting or blocking.
• The process by which the impregnated tissue is placed into a precisely arrange position in a mold containing medium which is then allowed to solidify
• Four types of tissue impregnation:
  1. Parrafin wax
  2. Celloidin
  3. Gelatin
  4. Plastic

Question 21

7. Blocking

Answer 21

Allows the medium to solidify to produce tissue block

Question 22

8. Trimming

Answer 22

• Process of removing excess wax after embedding
• Can use knife/blade or heated spatula

Question 23

9. Sectioning

Answer 23

• Also known as cutting or microtomy
• The process by which processed tissue is cut into uniformly thin slices to facilitate studies under microscope

Question 24

Microtome

Answer 24

machine or instrument used for cutting sections of tissue.

Question 25

Rocking Microtome

Answer 25

simplest and oldest type of microtome

Question 26

Rotary Microtome

Answer 26

for cutting serial sections of tissue specimen

Question 27

Sliding Microtome

Answer 27

most dangerous

Question 28

Freezing Microtome

Answer 28

for urgent surgical biopsies specimen

Question 29

Cryostat Microtome

Answer 29

also known as cold microtome, permits rapid penetration of tissue biopsies for surgical pathology

Question 30

Ultrathin Microtome

Answer 30

specimen for electron microscope

Question 31

10. Staining

Answer 31

Tissue constituent are demonstrated in sections by direct interaction with dye or staining solution producing coloration of the active tissue component. ❖ Heamtoxylin and Eosin Staining * Utilizes micro anatomical studies of tissue. * It is a regressive staining method

Question 32

❖ Heamtoxylin and Eosin Staining

Answer 32

- Utilizes micro anatomical studies of tissue. * It is a regressive staining method

Question 33

11. Mounting

Answer 33

* Mounting medium: the solution in which the specimen is embedded, generally under a cover glass. * It may be liquid, gum or resinous, soluble in water, alcohol or other solvents and be sealed from the external atmosphere by nonsoluble ringing media.

Question 34

12. Labelling

Answer 34

Date and time * Name of the patient * Specimen Number o C - Cytology specimen o A - Anatomical specimen o S - Surgical specimen

Question 35

Specimen for Examinations

Answer 35

Gynecological specimen Non-gynecological specimen Urine

Question 36

Gynecological specimen

Answer 36

- Performed regularly even in pregnant women without undue risk * Example: Vaginal smear

Question 36

Gynecological specimen

Answer 36

- Performed regularly even in pregnant women without undue risk * Example: Vaginal smear

Question 37

Non-gynecological specimen

Answer 37

Example: Respiratory tract specimens: a. Sputum b. Bronchoalveolar lavage (BAL)

Question 38

Urine

Answer 38

Determine the presence of urethral cancer