Cytology Review - NAVLE book Flashcards
Gram Stain
Used to classify bacteria
Gram (+) bacteria have teichoic acid in cell walls - Stain deep blue
Gram (-) bacteria have LPS in cell walls - Counterstained with Safranin or Fuchsin which stains red
Romanowsky Type Stain
Use on air-dried specimens
Aqueous based stains
Ex: Wright’s, Giemsa, Wright’s Giemsa, Leishman’s, Diff-Quik, DipStat
New Methylene Blue Stain
Aqueous Stain
Poor Cytoplasmic Detal - Excellent Nuclear & Nucleolar Visualization
Use for detection of: Nucleated cells, bacteria, fungi, yeast, NRBC’s, urine sediment (Sedi-Stain)
Used to count reticulocytes
Immunocytochemical Stains
Use antibodies against epitopes such as clusters of differentiation (CD antigens) to identify the cell line of origin
Limited by antibodies available
Neutrophils
13-16um in diameter
3-5 nuclear lobes
Females: occasionaly have Barr body (looks like small drumstick on end of one nuclear lobe)
Clear cytoplasm - dogs, cats, horses
Pink cytoplasm - ruminants
Macrophages
Medium-to-large sized - often > 25 um
Round to pleomorphic nuclei
Different morphologies:
a. Mononuclear: variable vacuolated
b. Epitheliod: Smooth blue cytoplasm w/ eccentric nucleus
c. Multinucleated giant cell
Eosinophils
13-16 um
3-5 nuclear lobes
Variable # of granules
Granules rod-shaped in cats
Lymphocytes
7-13 um
Single round nucleus
Uniformly high nucleus-to-cytoplasm (N:C) ratio
Plasma Cells
9-15 um long
Ovoid shaped
Eccentric Nucleus
Dark blue cytoplasm (d/t abundance of RER)
Perinuclear pale to clear zone (“halo”)
Mott Cells
Plasma Cells that are congested with Ig
Ig is contained withing pale blue structures called “Russell bodies”
Suppurative/Neutrophilic/Purulent Inflammation
Suggests active and likely acute process (but can be chronic)
Mainly bacterial infections
Degenerate neutrophils occur when neutrophils are exposed to toxic environment & KILLED rather than going to apoptosis
Karyolysis: Indistinct nucleus, cytoplasmic margin still intact
Pyknosis: Condensation & coalescing of nucleus into single dark, hyperchromic structure
Karyorrhexis: fragmentation/pyknosis of nuclear lobes
Eosinophilic Inflammation
When eosinophils are greater than 10% of overall inflammatory cell population
Consider:
- Allergic & Hypersensitivity Rxns
- Parasitic Infestation
- heartworm disease, Tissue migration of Dirofilaria immitis (cats), flea bite allergy - Fungal infection
- Cryptococcus neoformans in the CNS - Neoplasia
- Mast cell tumor, lymphoma
Granulomatous / Pyogranulomatous Inflammation
Consider:
- Foreign Body
- Fungal Infection
- Higher bacteria (e.g. Nocardia, Actinomyces, Mycobacterium)
Lymphocytic and/or Plasmacytic Inflammation
- Allergic rxns (e.g. vaccination sites)
- Viral infection
- Can be ass’d w/ chronic inflammation
- Nonspecific antigenic stimulation (e.g. IBD)
Mesenchymal Cells
Examples of mesenchymal cells: fibroblasts, osteoblasts, chondroblasts
Vary in shape: ovoid, stellate, fusiform, spindle, elongate
Can form disorganized clumps; NEVER form organized cohesive sheets
Epithelial Cells
Ex: Squamous cells, salivary epithelium, GI mucosa, hapatocytes, renal tubular cells
Vary in shape: round, angular, caudate to polygonal, can be spindle shaped
Form organized, cohesive sheets (as well as disorganized clumps)
Glandular epithelial cells will occasionally form acinar or rosette arrangement
Photo: Transitional Cell Carcinoma
Round Cells
Small to medium sized
Primarily have a round nucleus with round cell shape
Never form organized, cohesive sheets
Round Cell Type 1: Lymphocytes
Small, round w/ round nuclei
High N:C ratio
Nuclei display finely stippled chromatin pattern
Immature cells larger w/ open less intensely staining chromatin pattern
Lymphoblasts will have nucleoli
More immature lymphocytes = more likely they are malignant
Round Cells Type 2: Transmissible Veneral Tumor (TVT)
Canine Only: Found on prepuce, vulva, nose
Nuclei have clumped chromatin
Often 1-2 nucleoli
Moderate amounts of pale blue cytoplasm w/ distinct peripherally located vacuoles
Many mitotic figures usually seen w/ TVT
Round Cells Type 3: Plasma Cells
Generally round to ovoid
Nucleus often has coarsely clumped chromatin (“clockfaced” or “pinwheel”)
Almost always have distinct, prominent, pale-staining, perinuclear clearing area - this represents the Golgi zone (profound Ig production here)
Plasmacytomas usually benign (photo below)
Round Cell Types 4: Benign Cutaneous Histiocytoma
Canine only: young animals
Medium sized round cells
Fine chromatin pattern in nuclei; moderate pleomorphism; moderate amount of pale cytoplasm with distinct margins
Cytoplasm so pale that halo is only seen around nucleus
Round Cell Types 5: Mast Cell Tumor
Well-differentiated mast cells have abundant, small, dark purple granules that often obscure round nucleus
Granules will occasionally stain poorly with aqueous stains (e.g. Diff-Quik) - can use Toluidine blue or Giemsa
May see eosinophilic inflammation
Round Cell Types 6: Neuroendocrine Tumors
Cells look similar for all members (e.g. adrenal gland, beta cells of pancreas, thyroid epithelium, cells from a chemodectoma)
Numerous round, bare nuclei closely associated with one another in a bacground of cytoplasm, with rare intact cells
Rare intact cells: pale cytoplasm with indistinct margins
Criteria For Malignancy: 1. Nuclear
- Anisokaryosis
- Nuclear pleomorphism
- Multiplicity
- Coarse or atypical chromatin pattern
- Nuclear molding
Anisokaryosis
Variability in the size of the nuclei
Nuclear pleomorphism
Any variation from the shape of the nucleus expected for a tissue or type of cell
Nuclear Multiplicity
Multiple numbers of nuclei present within the same cell
Odd numbers of nuclei are especially bad
Nuclear Molding
The deformation of one nucleus by another nucleus or cell pressing against it
Criteria for Malignancy: 2. Nucleolar
- Multiplicity: more than expected # of nucleoli
- Pleomorphism: especially angular, elongate & polygonal forms
- Variable size
Criteria for Malignancy: 3. Cellular
- Pleomorphism
- Anisocytosis
- Abnormal granules or vacuoles
- Number: subjective
- Mitotic figures
- N:C ratios - High variability (except lymphocytes, basal cells - expected in these populations)
Anisocytosis
Different sized cells
Mitotic Figures
Abnormally high numbers or presence of bizarre ones
