Cytology

Question 1

indications for aspiration of lymph nodes?

Answer 1

enlargement,
pain, metastasis check

Question 2

reasons for enlargement of lymph nodes, broadly

Answer 2

hyperplasia,
inflammation or
neoplasia

Question 3

what is the cytology of a normal lymph node?

Answer 3

70-90% small lymphocytes, remainder medium to large lymphocytes, plasma cells, macrophages, few neutrophils, eosinophils, mast cells

Question 4

what causes reactive hyperplasia of a lymph node? how does the cytology change?

Answer 4

• due to antigenic stimulation in area of drainage
• small lymphocytes still predominate
• increase in large lymphocytes and plasma cells
• may see Russell bodies inside plasma cells (called Mott cell)
in chronic stimulation

Question 5

what is lymphadenitis? what can we see cytologically? What will we see in the case of a mycobacterial infection?

Answer 5

-enlargement in one or more lymph nodes, usually due to infection
• an increase in neutrophils, eosinophils, or macrophages
• the organism may be present in the lymph node
• mycobacterial infection typically causes granulomatous inflammation

Question 6

what is lymphoma? What will we see cytologically? What are some differences between species?

Answer 6

-a cancer of the lymphatic system
• homogenous population of lymphocytes
• mitotic figures frequent
• in the dog most lymphomas are large cell type
• in cats and horses a mixed cell size is more common
• most lymphomas are treatable in small animals

Question 7

common types of metastatic neoplasia

Answer 7

• mast cell tumors,
melanoma, malignant
histiocytic tumours
• carcinomas, and
potentially any malignant tumor

Question 8

best chance of distinguishing cancer via cytology

Answer 8

• best applied to neoplasms that will exfoliate readily
• clinical information very important!
• caution to distinguish hyperplasia from neoplasia
• often best combined with histopathology
• can at least guide initial case management and/or direct further diagnostics

Question 9

cytological classifications of cancer

Answer 9

1. epithelial
2. mesenchymal cell (spindle cell, stromal cell)
3. round cell tumors

Question 10

characteristics of an epithelial cell cancer, and examples of types

Answer 10

• should see cell borders, tend to adhere to each other, form tubules, acini, sheets
• Adenoma, carcinoma,
adenocarcinoma,
transitional cell carcinoma, squamous cell carcinoma, etc.

Question 11

characteristics of a mesechymal cell cancer, and examples of types

Answer 11

• indistinct cytoplasmic boundaries
• often long cytoplasmic tails (spindles)
• soft tissue sarcoma, fibroma, hemangiosarcoma,
osteosarcoma, chondrosarcoma, etc.

Question 12

characteristics of round cells tumors

Answer 12

• discrete round shape and nucleus
• do not adhere to each other, single, discrete cells
• can often recognize the specific neoplasm

Question 13

cytological features of cancer

Answer 13

1. Size: neoplastic cells may be larger than their benign counterpart
2. Nuclear enlargement: increased nuclear to cytoplasmic ratio (N/C ratio)
3. Nucleoli: increased number and size compared to benign
   counterpart
4. Hyperchromasia: nuclear and cytoplasmic hyperchromasia is a common feature
   of neoplastic cells
5. Increased and abnormal
   mitotic figures
   • neoplastic cells often
   have an increased
   number of cells in
   mitosis
   • gross structural gene
   changes may manifest
   with abnormally
   distributed
   chromosomes
   during metaphase

Question 14

types of mass lesions that are not malignant cancer but can be tricky to differentiate cytologically

Answer 14

1. inclusion cysts
2. sialocele
3. abscess

Question 15

what is an inclusion cyst?

Answer 15

-degenerating epithelial cells, cholesterol crystals, macrophages

Question 16

what is a sialocele?

Answer 16

submandibular swelling due to obstructed salivary duct

Question 17

how can an abscess trick us into thinking it is a neoplasm

Answer 17

chronic
abscessation
may result in
formation of a
firm fibrous
capsule that
feels similar to
some neoplasms

Question 18

what is the use of a transtracheal wash? do we need a lot of equipment?

Answer 18

-to view respiratory cytology
• sample generally representative only of the trachea and larger conducting airways

-sedation may be
necessary, otherwise little equipment

Question 19

what is the use of a bronchoalveolar lavage? what equipment do we need?

Answer 19

sedation +/-
general anaesthetic and intubation necessary
• sample generally representative of the smaller bronchi and possibly alveoli

Question 20

are cell counts useful for respiratory cytology

Answer 20

-limited value due to cells entrapped in mucus, variable saline recovery

Question 21

is total protein a useful metric for respiratory cytology?

Answer 21

questionable value due to variable dilution of respiratory secretions with saline wash

Question 22

what do we often see on a respiratory cytology slide?

Answer 22

• normally abundant mucus
• alveolar macrophages if sampled small airways
• cuboidal epithelial cells (pneumocytes) from small
airways
• ciliated columnar cells from larger airways
• goblet cells
• moderate number of lymphocytes
• neutrophils, mast cells, eosinophils - rare

Question 23

what are the diagnostic signs of aspiration pneumonia?

Answer 23

• very debilitated animals,
megaesophagus,
myasthenia gravis,
iatrogenic
• marked inflammation,
mixed bacterial
morphologies, plant
material, keratinizing
squamous cells

Question 24

t are some cytologic signs of chronic non-spetic airway inflammation?

Answer 24

• suppurative with nondegenerate neutrophils
• or eosinophilic inflammation +/- mast cells
• Curshmanns spirals are dislodged mucus plugs from small airways seen in chronic inflammation

Question 25

When do we want to take a bone marrow cytology sample?

Answer 25

-unexplained or persistent cytopenia -abnormal cells in circulation -bone marrow infection -suspect leukemia or metastasis -iron deficiency

Question 26

what will we find in a acytological sample of body cavity fluids?

Answer 26

-cell counts, small animals < horse < cow -protein -predominantly mononuclear cells: monocytes, macrophages, lymphocytes -rarely neutrophils: can have nuclear changes, phagocytosed bacteria

Question 27

what type of fluid samples will require centrifugation ofr analysis?

Answer 27

fluids with low cell counts (<20x10^9/L) ie. abdominal fluid, pleural fluid

Question 28

what is effusion? what are the ways it can occur

Answer 28

excess fluid accumulation. can be due to transudation or exudate

Question 29

what is exudate?

Answer 29

-tissue inflammation leads to increased vascular permeability with leakage and active movement of protein and cells into body cavities

Question 30

what is transudation?

Answer 30

-increased intravascualr pressure leads to transudation of small molecules eg. water, electrolytes -doesnt increase cellularity or protein

Question 31

what will we see with supprative spetic inflammation

Answer 31

micro-organisms observed on smear, along with neutrophils

Question 32

how do we judge the state of preservation of a neutrophil cytologically?

Answer 32

-state of preservation is judges by nuclear criteria outside of the bloodstream, versus cytoplasmic criteria on blood smears

Question 33

what are the three major nuclear changes we can observe in neutrophils and what do they mean?

Answer 33

1. pyknotic: compact nuclei of dying neutrophils - cell death 2. karyorrhetic: fragmented nuclei of neutrophils undergoing cell death 3. karyolytic: lysed nuclei in neutrophils exposed to bacterial toxins - degenerate cells

Question 34

what are mesothelial cells? how can they appear cytologically?

Answer 34

lining cells of abdominal and pleural cavity, may resemble macrophages or appear neoplastic

Question 35

what will microbial organisms look like if we see them on a cytological sample?

Answer 35

*artifact can look a lot like bacteria • should be rod-shaped, filamentous, or cocci if bacteria • should be phagocytosed if in vivo occurrence • definitive diagnosis may require special stains and/or culture • protozoa and fungal organisms have unique appearance ... cytology can provide definitive diagnosis

Question 36

what are some common pigments and crystals that we can see cytologically?

Answer 36

extravascular red cells are phagocytosed by macrophages and broken down into heme pigments that stain from green-black to brown • iron-free heme is occasionally seen as hematoidin • cholesterol crystals are common in cysts with chronic non-inflammatory cell degeneration • melanin may be seen phagocytosed by macrophages or in tumor cells (melanoma)

Question 37

What is bile peritonitis? What does its effusion look like?

Answer 37

-• “chemical” peritonitis, neutrophils and macrophages, bile pigment -bile incites inflammatory response -exudate

Question 38

what effusion do we see with congestive heart failure?

Answer 38

• commonly modified transudates with slightly elevated cell concentration and protein content • erythrophagocytosis common

Question 39

what effusion do we see with chronic hepatic disease?

Answer 39

• commonly transudates due to low serum albumin concentration • low protein and low cell count

Question 40

what are the characteristics of FIP effusion?

Answer 40

-exudative • pyogranulomatous vasculitis • high protein exudate, yellow color • low to moderate elevation in cell count • well preserved neutrophils

Question 41

what are the characteristics of chylothorax and associated effusion?

Answer 41

-exudate • leakage of chylous fluid from the thoracic duct into the thoracic cavity, or, less commonly, into the abdominal cavity • milky white appearance due to high triglyceride content • lymphocyte rich

Question 42

when will we see an effusion due to intestinal rupture and what will it look like?

Answer 42

-exudate • secondary to obstruction • most common in horses • a mixture of bacteria and plant material -turbid, brown fluid

Question 43

what will we see with pyothorax or pyoperitoneum, and what does the effusion look like?

Answer 43

-exudate • suppurative inflammation with neutrophil degeneration according to the toxins elaborated by the organisms • Actinomyces spp. and/or Nocardia spp. infection result in grossly visible bacterial colonies (“sulfur granules”)

Question 44

what is uroabdomen and what does the effusion look like?

Answer 44

• ruptured urinary bladder or ureter secondary to lower urinary tract obstruction • diagnosis based on creatinine concentration in abdominal fluid or presence of urinary crystals • mild chemical inflammation