Embedding

Question 1

Embedding

Answer 1

Enclosing the tissue in infiltration medium, usually paraffin and then allowing the medium to solidify

Question 2

Embedding Medium

Answer 2

The material used to enclose and support processed tissue, usually paraffin

Question 3

Cryoconsole

Answer 3

Cold section of the embedding station used to solidify paraffin blocks

Question 4

Thermoconsole

Answer 4

Used to heat processed tissue and paraffin for embedding

Question 5

Molds

Answer 5

Contain the molten wax and tissue until fully cooled and solid, gives the block its shape and size

Question 6

Skin Orientation

Answer 6

Embedded on edge and with all epidermal surfaces facing one side of the mold in the same direction

Question 7

Tubular Structure Orientation

Answer 7

In cross section so all layers of the tube are visible; lumen, mucosa, submucosa, and muscle

Question 8

Structures with a Wall Orientation

Answer 8

Ex: cysts or gallbladder
On edge (like skin) so all layers are visible

Question 9

Bone Orientation

Answer 9

At an angle to reduce the surface area in contact with the blade while sectioning

Question 10

Structures Containing Mucosa Orientation

Answer 10

In cross section so all layers are visible

Question 11

Aggregate specimen orientation (Like endometrial currettings)

Answer 11

In a line down the center of the block if possible, or clustered together

Question 12

Effect of overheated embedding medium

Answer 12

Hard, dry, brittle tissue

Question 13

Optimum temperature of paraffin for embedding

Answer 13

55-58C

Question 14

Paraffin melting point with respect to thickness, hardness, and ribbons

Answer 14

High melting point gives good thin sections, more support for hard things like bone, and less good for ribbons
lower melting point gives less good thin sections, less support for hard tissues, and ribbons more easily

Question 15

Importance of preventative maintenance and QC procedures to ensure instrument reliability

Answer 15

Change solutions regularly to prevent contamination
Temperature logs to prevent over hardened tissue
Regular maintenance by a service technician to ensure optimal function

Question 16

Proper method for embedding a tissue specimen

Answer 16

Open one cassette at a time
Fill mold with molten wax
add specimen
generally orient specimen
start cooling
complete orientation
complete cooling
adhere identifying cassette lid
leave on cold plate to finish hardening

Question 17

Two ways orientation can be communicated from grosser to embedder

Answer 17

Mark specimen with ink at the grossing station

Instructions on the side of the cassette

Question 18

Effects of embedding tissue horizontally

Answer 18

Increases surface area in contact with the blade, can make sectioning more difficult, especially with bone specimens

Question 19

Effects of embedding on multiple planes

Answer 19

Difficult to get all the relevant tissue in one section

May loose on piece of tissue while trimming to get the other in the same section

Question 20

Tissue thickness and embedding techniques

Answer 20

Hard to embed tissue that is grossed too thickly, also tends to result in mushy and hard to section tissue

Question 21

At what stage should embedding orientation be decided?

Answer 21

At the grossing station by the pathologist or PA

Question 22

What is the most critical step in embedding?

Answer 22

Orientation

Question 23

What is the best paraffin melting point for routine work?

Answer 23

55-58C

Question 24

Negative result when: Embedding paraffin is overheated?

Answer 24

over hardened or brittle tissue that is difficult to section, difficult to get ribbons

Question 25

Negative result when: Soft/lower melting point paraffin is used to embed bone?

Answer 25

Not enough support to get thin, crisp sections

Question 26

Negative result when: Sections are not embedded flat at the same level?

Answer 26

You can lose a lot of valuable tissue during trimming while trying to get all the pieces in one plane Or you might lose one piece of tissue while getting to others

Question 27

Negative result when: A section of bone is not embedded at an angle?

Answer 27

Harder to section because the angle helps reduce the surface in contact with the blade at any given time

Question 28

Negative result when: The lumen is not visible in a section of fallopian tube?

Answer 28

Unable to visualize all the relevant layers (mucosa, submucosa, muscle) necessary for diagnosis

Question 29

Negative result when: Forceps are not wiped with gauze between samples?

Answer 29

Carryover of tissue between samples (forceps metastasis), cross contamination of samples

Question 30

Negative result when: Tissue is cut too thick at the grossing table?

Answer 30

Mush tissue comes out of the processor might not fit into the cassette or mold doesn't section well, might explode on the water bath

Question 31

Negative result when: The side of the cassette is not read before embedding?

Answer 31

incorrect orientation for type of tissue | may miss the correct number of tissue pieces to be embedded

Question 32

Negative result when: lens paper containing the tissue is not opened completely?

Answer 32

Might miss small fragments that should have been embedded

Question 33

Negative result when: Softer paraffin (low melting point) is used to cut kidney at 2 microns?

Answer 33

Too soft to get crisp sections, lots of compression of sections High melting point paraffin is better for thin sections

Question 34

Negative result when: Blocks aren't cooled as rapidly as possible on the embedding center?

Answer 34

Tissue on edge may fall out of alignment | ice crystals may form

Question 35

Embedding material for Electron Microscopy

Answer 35

Epoxy resins

Question 36

Embedding material for Nervous System Tissue

Answer 36

Celloidin

Question 37

Embedding material for Un-decalcified Bone

Answer 37

Glycol Methacrylate (GMA)

Question 38

Embedding material for Fatty Tissues

Answer 38

Carbowax (water soluble)

Question 39

Embedding material for Frozen Sections

Answer 39

30% Sucrose

Question 40

What do you do with floaters in the embedding center?

Answer 40

Put in a blank cassette, label with your initials, the date, and embed the tissue to later identify

Question 41

What do you do if you chunk a block but there is still tissue left?

Answer 41

Melt down the block and re-embed, especially if you still need more sections from the block

Question 42

What if a cassette label says 2 pieces, but you only find 1?

Answer 42

Check the embedding center and your immediate surroundings for floaters/jumpers Check with supervisor Check trash, etc.

Question 43

Vas deferens (tubular structure) is embedded longitudinally, rather than in cross-section. What do you do?

Answer 43

Check with the pathologist to confirm whether they wanted longitudinal orientation Melt down and re-embed in cross-section

Question 44

Pathologist sees squamous skin calls on a prostate sample, what could have caused this?

Answer 44

Lack of gloves while embedding or picking up slides in the water bath Wear gloves/ skim water bath regularly/don't put your fingers in the water-bath

Question 45

Open cassette to embed a derm, but there's no sample inside

Answer 45

Check immediate surroundings, trash, supervisor, alert lab