Histopathology Lab (Types of Biopsies)

Histology

is the microscopic study of normal tissues.

Histopathology

is the microscopic study of tissues affected by a disease.

histologic or histopathologic technique

The procedures used to prepare these tissues are termed as _________or ___________ and it starts with the collection of samples.

· How do we acquire these samples?

· Through surgery, biopsy, or autopsy.

Bio

Means life

Psy

to see, appearance

biopsy

· A process of excision or examination of tissue sample coming from a living person.

biopsy

The gold standard in diagnosing malignant disease

types of biopsy

· Fine needle aspiration biopsy

· Core needle biopsy

· Incisional biopsy

· Excisional biopsy

· Punch biopsy

· Shave biopsy

· Cutaneous biopsy

· Wedge biopsy

· Curettings

· Exfoliative cytology

Fine needle aspiration biopsy (FNAB)-

least invasive, only uses the smallest needle to aspirate cells from the area of abnormality.

Core needle biopsy

removes not only cells but also a small amount of surrounding tissue.

Incisional biopsy

- takes only a small part of an organ, tissue, or tumor. If the organ, tissue, or tumor is found to be cancerous, additional surgery is needed to remove the whole tumor.

Excisional biopsy-

generally removes the whole tumor.

Punch biopsy-

used for obtaining diagnostic full-thickness of skin specimens. The procedure uses a circular blade that is rotated down to epidermis, dermis, and into the subcutaneous fats forming a 3-4mm cylindrical core of skin tissue sample.

Cutaneous biopsy-

also used for skin biopsy. For diagnosing melanoma

Shave biopsy

usually done in the skin. Fragments are "shaved" from the surface.

Wedge biopsy-

an incision from a solid organ "wedge" shaped.

Curetting-

uses scoops or spoon-like apparatus to remove tissue growths from the body cavity such as endometrium or cervical canal.

Exfoliative cytology-

a microscopic study of desquamated cells from epithelial surfaces. Used to diagnose cervical cancer

pap smear

best example of exfoliative cytology

formalin

Tissue samples usually come in the laboratory in fixative such as __________ or sometimes they arrive fresh and must be immediately fixed.

- patients basic information

- clinical history

- sample description

- site of origin

They arrive in the lab together with the ________, ____________, _________ and it's ____________

Surgery

S22-0001

Autopsy

A22-0001

Cytology

C22-0001

fresh tissues

-· are temporary and is only observed for a shorter period, prone to lysis and rapid changes in cell structure.

- · Only done when there's a need for immediate evaluation.

preserved tissue

· are permanent, better, more effective means of studying tissues and for long time keeping, stained, and mounted in glass slides with coverslips.

methods of fresh tissue examination

1. teasing or dissociation

2. squash preparation

3. smear preparation

4. touch preparation

5. frozen section

3 types of smear preparation

- streaking

- spreading

- pull-apart

teasing or dissociation

- The selected tissue is immersed in NSS or Ringer's solution in a watch glass or petri dish, dissected with a needle. Pieces of tissues are viewed in a microscope in a wet preparation underneath a coverslip.

- Cells are examined in a living state allowing movement and mitotic division to be observed.

squash preparation

- A process where a small tissue is crushed or forcibly compressed between two slides or a coverslip.

- If necessary, Supravital stain may be used by allowing to be absorbed by the cells or tissue.

smear preparation

- The general rule is smears are made by spreading portions of specimen over the surface of the slide using a platinum loop.

- Alternatively making a smear using a second slide to obtain a uniform distribution of secretion or sample.

streaking

using an applicator stick or platinum loop, the sample (body fluid) is rapidly and gently applied in direct or zigzag line throughout the slide.

speading

a selected portion of a sample is transferred to a clean slide teasing the mucous strands apart with an applicator stick. More tedious than streaking. Commonly done with sputum, mucoid secretions, bronchial aspirates

Pull apart

done by dropping a sample into a clean slide and facing it to another slide allowing to first to disperse evenly in both slides. Pulling both slides in opposite directions.

touch preparation

- Smear preparation whereby the surface of a freshly cut tissue is brought into contact and pressed on the surface of a clean glass slide allowing cells to be transferred into the slide.

frozen section

- Used for rapid diagnosis.

- The surgeon needs to know if his/her tissue section is adequate before closing.

- Usually done on muscle or nerve biopsies as well as on surgically removed tumors.

- Morphological detail is inferior to waxed tissue section.

How frozen section is done:

- Fresh tissue is frozen on a microtome with CO2 or on a cryostat with a temperature of -10deg cel to -20deg cel.

- Frozen sections are mounted on a slide, fixed immediately, stained using similar techniques used in waxed tissue sections.

advantage of frozen section

- Less ventilation is needed.

- Less equipment is used.

disadvantage of frozen section

- poor quality of morphological detail

histopathologic technique for preserved tissue

1. Numbering

2. Fixation

3. Decalcification (optional)

4. Dehydration

5. Clearing

6. Infiltration (impregnation)

7. Embedding

8. Trimming

9. Section-cutting (microtomy)

10. Staining

11. Mounting