Special stains and IHC

Question 1

Which stain can be used to assess the basement membrane?

Answer 1

Periodic acid Schiff

Question 2

Ziehl-Neelson staining can detect mycobacteria and which other weakly acid fast organisms?

Answer 2

Rhodococcus equi and Nocardia Spp

Question 3

Which part of a fungus does Grocott’s Methenamine Silver (GMS) specifically stain?

Answer 3

Polysaccharide components of the fungal cell wall

Question 4

What does Mayer’s Mucicarmine stain?

Answer 4

Polysaccharides on the capsule of Cryptococcus neoformans and mucins.

Question 5

What is Gomori’s One-Step Trichrome stain used for?

Answer 5

For distinguishing collagen and smooth muscle fibers

Question 6

What is Masson’s Trichrome stain used for?

Answer 6

Used for distinguishing cells from surrounding connective tissue which has several variants and is probably the trichrome most used in histopathology. Black nuclei, red cytoplasm (including muscle), blue or green collagen (including fine fibers), cartilage and mucus

Question 7

What is Russel-Movat Pentachrome stain used for?

Answer 7

Used for simultaneous demonstration of muscle, elastic fibers, collagen/reticular fibers, ground substance and fibrinoid in tissues

Question 8

What are Oil Red O and Sudan Black B stains used for?

Answer 8

Used for staining lipids in frozen sections and some lipoproteins on paraffin sections.

Lipids, including triglycerides (which necessarily are neutral). Oil Red O stains only the most hydrophobic lipids (triglycerides and cholesterol esters). Sudan Black B stains these and also phospholipids and sphingomyelins, which are less hydrophobic

Question 9

What is Orcein stain used for?

Answer 9

Used for staining elastic fibers

Question 10

What is Lendrum’s Method (Picro-Mallory Stain) used for?

Answer 10

For staining fibrin

Question 11

What does Congo Red stain show?

Answer 11

Amyloid deposits

Question 12

What is Masson-Fontana stain used for?

Answer 12

Used for the detection of melanin

Question 13

What is Alcian Blue stain used for?

Answer 13

Used in identifying mucins and glycosaminoglycans e.g. hyaluronic acid

Question 14

Which inflammatory cell stains with Giemsa Stain?

Answer 14

Mast cells

Question 15

What are the Brown-Hopps and Brown-Brenn stains?

Answer 15

Modifications of the Gram stain and are used for demonstration of Gram-negative bacteria and rickettsia

Question 16

Which special stain can be used to identify Leishmania?

Answer 16

Giemsa

Question 17

What type of molecule does PAS stain?

Answer 17

Mucopolysaccharides, especially glycogen

Question 18

What does Verhoff von Gieson stain?

Answer 18

It is a silver stain used to demonstrate and evaluate the quantity and quality of tissue elastic fibers. Positive staining is perceived as black.

Question 19

What colour do Mycobacteria stain with Ziehl-Neelson?

Answer 19

Red

Question 20

Smooth muscle and keratin stain pink-red, collagen stains blue-green, and elastic fibers appear black with which special stain?

Answer 20

Masson’s Trichrome

Question 21

How do you differentiate Langerhans from dermal dendritic cells? Both stain for IBA1 on IHC

Answer 21

Langerhans cells are CD204 -ve and E-cadherin +ve

Dermal dendritic cells show variable CD204 staining and are E-cadherin -ve

Question 22

Which cells are CD3 +ve?

Answer 22

T cells

Question 23

Which cells are CD20 +ve?

Answer 23

B cells (some cross over reported with neoplastic T cells in epitheliotropic lymphoma)

Question 24

Which cells stain with CD79a?

Answer 24

B cells

Question 25

Which cells are vimentin +ve?

Answer 25

Vimentin is present in cells of mesenchymal origin and in mesenchymal derived tumours such as lymphomas, sarcomas and melanomas

Question 26

IHC to detect CD18 and MHC class II was equally effective in staining histiocytomas, although lymphosarcoma must be ruled out through the use of ____ and ____ IHC

Answer 26

CD3 and CD79a

Question 27

Which markers can be used for IHC to identify melanomas?

Answer 27

Melan-A, PNL-2, TRP-1 (tyrosine related protein), and TRP-2

Question 28

Pancytokeratin is an IHC marker for which type of cells?

Answer 28

Epithelial cells

Question 29

In pagetoid reticulosis, are T cells alpha-beta or gamma-delta positive?

Answer 29

All are gamma-delta positive

Question 30

Which IHC stains can be used to identify B cells?

Answer 30

CD79a, CD20, Pax5

Question 31

Name two neural crest cell markers

Answer 31

S-100 and neuron specific enolase (NSE)

Question 32

What can you use to help assess cell morphology in highly pigmented melanocytes?

Answer 32

Bleach

Question 33

Name three prognostic IHC markers for melanomas

Answer 33

1. FoxP3 and IDO 2. MCAM/CD146 3. C-kit receptor 4. Nuclear survivin 5. COX-2 6. Ki67

Question 34

Name four plasma cell markers

Answer 34

``` CD79a CD20 CD18 Immunoglobulin kappa light chains MUM1/IRF4 ```

Question 35

Other than plasmacytomas, which other tumour can be positive for MUM1/IRF4?

Answer 35

Histiocytoma

Question 36

Histiocytoma in dogs stains with which markers?

Answer 36

CD1a CD11c/CD18 E-cadherin (specific to Langerhans cells) Iba1

Question 37

Iba1 is marker for which cell lineage?

Answer 37

Monocyte/macrophage lineage cells in dogs and cats

Question 38

How many mitotic figures PHPF are in grade 1, grade 2 and grade 3 (Patnaik) MCTs?

Answer 38

Grade 1 = 0 Grade 2 = 0-2 Grade 3 = 3-6

Question 39

How many mitoses PHPF are in low and high grade (Kiupel) MCTs?

Answer 39

``` Low = <7 in 10 HPF High = at least 7 in 10 HPF ```

Question 40

What IHC markers can be used for MCTs?

Answer 40

Mast cell tryptase | CD117/c-kit

Question 41

Which cytokeratins can help distinguish SCC from basosquamous variants in dogs?

Answer 41

Cytokeratin 6 and 10

Question 42

Weibel-Palade bodies are specific markers for which cells?

Answer 42

Endothelial cells

Question 43

Cytokeratin positive; CK7/8 (CAM 5.2) and CK13 are relatively specific markers for which type of epithelia?

Answer 43

Glandular

Question 44

Name macrophage IHC markers

Answer 44

CD68 MAC 387 Lysozyme