Lecture 21 11/21/24 Flashcards
(26 cards)
How does cytology compare to histopathology?
cytology:
-evaluation of individual cells
-sampling of cells spread directly on glass slide
-specimens can be collected and slides prepared in most clinics
-evaluated by clinical pathologists
histo:
-evaluation of tissue sections
-sections of formalin-fixed tissue
-tissue collected by veterinarian but processed by histo lab
-evaluated by anatomic pathologists
What are the indications for cytology?
-characterize a detected abnormality
-cancer staging
What are the pros of cytology?
-quick and easy
-relatively safe to collect
-quick results
-often less expensive
-better fine detail of individual cells and infectious agents
What are the cons of cytology?
-no tissue architecture
-only sampling a very small area
What are the pros of histopath?
-evaluation of tissue architecture
-larger area is sampled
What are the cons of histopath?
-longer turnaround time
-usually requires anesthesia and more equipment
-more expensive
-more risk of complications
-less cellular detail
What are the sampling techniques for soft tissue cytology?
fine needle techniques:
-pin cushion/stab technique
-fine needle aspirate
exfoliative:
-impression smears
Why is formalin bad for cytology?
formalin drastically alters the staining properties of cells and renders the cytology non-diagnostic
What are the steps of cytology slide evaluation?
-evaluate slide quality
-identify types of cells present, including inflammatory and non-inflammatory cells
What are the characteristics of a high quality slide?
having all of the following:
-adequate cellularity
-intact cells
-well-spread monolayer of cells
What are the causes of neutrophilic and/or macrophagic inflammation?
-bacteria
-fungus
-some parasites
-foreign body
-necrosis
-immune-mediated disease
What are the causes of eosinophilic inflammation?
-parasites
-arthropod bites/stings
-hypersensitivities
-neoplasia
What are the causes of small lymphocytes on cytology slides?
-immune stimulation
-tumor-associated lymphocytes (non-lymphoid tumors)
-small cell lymphoma
Which aspects of cells should be evaluated during cytology?
-whether the cell type is normally expected at the site
-whether the cells are cytologically atypical
-how the cells correlate to other clinical findings
What are the cytologic features of epithelial cells?
-exfoliate in clusters
-variable shape depending on type of epithelium
What are the cytologic features of mesenchymal cells?
-exfoliate individually
-spindled, fusiform, irregular to stellate shape
What are the cytologic features of round cells?
-exfoliate individually
-round cell shape
-can often diagnose with confidence on cytology
What is a non-neoplastic example of round cells on cytology?
inflammatory cells
What are examples of round cell tumors?
-lymphoma
-plasma cell tumors
-mast cell tumors
-cutaneous histiocytoma
-histiocytic sarcoma
-transmissible venereal tumor
What are the characteristics of benign vs malignant classification?
-histopath. better for determination
-takes anatomic location, other clinical information, and typical biologic behavior into account
-cytologic features are more commonly noted in malignant lesions
What are the cytologic criteria of malignancy?
-pleomorphism/anisocytosis/anisokaryosis
-macrocytosis
-multinucleation with intracellular anisokaryosis
-numerous nucleoli
-increased nuclear size
-abnormal mitotic figures
What are the characteristics of inflammation and epithelial dysplasia?
-inflammation or irritation can cause epithelial cells to appear morphologically abnormal
-difficult to distinguish from neoplasia
What are the characteristics of inflammation and reactive fibroblasts?
-fibroblasts can proliferate in response to inflammation and appear morphologically abnormal
-difficult to distinguish from neoplasia
What is important about hyperplastic epithelium?
can look similar to normal tissue or to well-differentiated epithelial neoplasia
