Cytology Flashcards
indications for aspiration of lymph nodes?
enlargement,
pain, metastasis check
reasons for enlargement of lymph nodes, broadly
hyperplasia,
inflammation or
neoplasia
what is the cytology of a normal lymph node?
70-90% small lymphocytes, remainder medium to large lymphocytes, plasma cells, macrophages, few neutrophils, eosinophils, mast cells
what causes reactive hyperplasia of a lymph node? how does the cytology change?
• 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
what is lymphadenitis? what can we see cytologically? What will we see in the case of a mycobacterial infection?
-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
what is lymphoma? What will we see cytologically? What are some differences between species?
-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
common types of metastatic neoplasia
• mast cell tumors,
melanoma, malignant
histiocytic tumours
• carcinomas, and
potentially any malignant tumor
best chance of distinguishing cancer via cytology
• 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
cytological classifications of cancer
- epithelial
- mesenchymal cell (spindle cell, stromal cell)
- round cell tumors
characteristics of an epithelial cell cancer, and examples of types
• should see cell borders, tend to adhere to each other, form tubules, acini, sheets
• Adenoma, carcinoma,
adenocarcinoma,
transitional cell carcinoma, squamous cell carcinoma, etc.
characteristics of a mesechymal cell cancer, and examples of types
• indistinct cytoplasmic boundaries
• often long cytoplasmic tails (spindles)
• soft tissue sarcoma, fibroma, hemangiosarcoma,
osteosarcoma, chondrosarcoma, etc.
characteristics of round cells tumors
• discrete round shape and nucleus
• do not adhere to each other, single, discrete cells
• can often recognize the specific neoplasm
cytological features of cancer
- Size: neoplastic cells may be larger than their benign counterpart
- Nuclear enlargement: increased nuclear to cytoplasmic ratio (N/C ratio)
- Nucleoli: increased number and size compared to benign
counterpart - Hyperchromasia: nuclear and cytoplasmic hyperchromasia is a common feature
of neoplastic cells - 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
types of mass lesions that are not malignant cancer but can be tricky to differentiate cytologically
- inclusion cysts
- sialocele
- abscess
what is an inclusion cyst?
-degenerating epithelial cells, cholesterol crystals, macrophages
what is a sialocele?
submandibular swelling due to obstructed salivary duct
how can an abscess trick us into thinking it is a neoplasm
chronic
abscessation
may result in
formation of a
firm fibrous
capsule that
feels similar to
some neoplasms
what is the use of a transtracheal wash? do we need a lot of equipment?
-to view respiratory cytology
• sample generally representative only of the trachea and larger conducting airways
-sedation may be
necessary, otherwise little equipment
what is the use of a bronchoalveolar lavage? what equipment do we need?
sedation +/-
general anaesthetic and intubation necessary
• sample generally representative of the smaller bronchi and possibly alveoli
are cell counts useful for respiratory cytology
-limited value due to cells entrapped in mucus, variable saline recovery
is total protein a useful metric for respiratory cytology?
questionable value due to variable dilution of respiratory secretions with saline wash
what do we often see on a respiratory cytology slide?
• 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
what are the diagnostic signs of aspiration pneumonia?
• very debilitated animals,
megaesophagus,
myasthenia gravis,
iatrogenic
• marked inflammation,
mixed bacterial
morphologies, plant
material, keratinizing
squamous cells
t are some cytologic signs of chronic non-spetic airway inflammation?
• suppurative with nondegenerate neutrophils
• or eosinophilic inflammation +/- mast cells
• Curshmanns spirals are dislodged mucus plugs from small airways seen in chronic inflammation
When do we want to take a bone marrow cytology sample?
-unexplained or persistent cytopenia
-abnormal cells in circulation
-bone marrow infection
-suspect leukemia or metastasis
-iron deficiency
what will we find in a acytological sample of body cavity fluids?
-cell counts, small animals < horse < cow
-protein
-predominantly mononuclear cells: monocytes, macrophages, lymphocytes
-rarely neutrophils: can have nuclear changes, phagocytosed bacteria
what type of fluid samples will require centrifugation ofr analysis?
fluids with low cell counts (<20x10^9/L) ie. abdominal fluid, pleural fluid
what is effusion? what are the ways it can occur
excess fluid accumulation. can be due to transudation or exudate
what is exudate?
-tissue inflammation leads to increased vascular permeability with leakage and active movement of protein and cells into body cavities
what is transudation?
-increased intravascualr pressure leads to transudation of small molecules eg. water, electrolytes
-doesnt increase cellularity or protein
what will we see with supprative spetic inflammation
micro-organisms observed on smear, along with neutrophils
how do we judge the state of preservation of a neutrophil cytologically?
-state of preservation is judges by nuclear criteria outside of the bloodstream, versus cytoplasmic criteria on blood smears
what are the three major nuclear changes we can observe in neutrophils and what do they mean?
- pyknotic: compact nuclei of dying neutrophils - cell death
- karyorrhetic: fragmented nuclei of neutrophils undergoing cell death
- karyolytic: lysed nuclei in neutrophils exposed to bacterial toxins - degenerate cells
what are mesothelial cells? how can they appear cytologically?
lining cells of abdominal and pleural cavity, may resemble macrophages or appear neoplastic
what will microbial organisms look like if we see them on a cytological sample?
*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
what are some common pigments and crystals that we can see cytologically?
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)
What is bile peritonitis? What does its effusion look like?
-• “chemical” peritonitis, neutrophils and
macrophages, bile pigment
-bile incites inflammatory response
-exudate
what effusion do we see with congestive heart failure?
• commonly modified transudates with slightly elevated cell
concentration and protein content
• erythrophagocytosis common
what effusion do we see with chronic hepatic disease?
• commonly transudates due to low serum albumin
concentration
• low protein and low cell count
what are the characteristics of FIP effusion?
-exudative
• pyogranulomatous vasculitis
• high protein exudate, yellow color
• low to moderate elevation in cell count
• well preserved neutrophils
what are the characteristics of chylothorax and associated effusion?
-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
when will we see an effusion due to intestinal rupture and what will it look like?
-exudate
• secondary to obstruction
• most common in horses
• a mixture of bacteria and plant material
-turbid, brown fluid
what will we see with pyothorax or pyoperitoneum, and what does the effusion look like?
-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”)
what is uroabdomen and what does the effusion look like?
• 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
