Intro to Cytology Flashcards
when do you perform cytology?
- lump and bumps
- enlarged or abnormal organs (lymph nodes)
- fluids/discharge: effusion (cavity, synovial), airways, draining lesions
what are the methods to perform cytology?
- fine need biopsy/aspirate
- impression
- tissue scrape
- swab
- fluids: CSF, synovial, airway wash
what are the advantages of cytology compared to histopathology? (6) and include tips for performing (3)
- relatively easy
- minimally invasive
- low-cost
- good screening test
- faster turnaround time
- excellent cellular detail (but lacks tissue architecture!! EXAM QUESTION)
tips: use different techniques/methods, minimize time from collection to preparation, prepare samples gently
what is the first question you ask when examining a cytology sample? what is the second?
- is it cellular? need sufficient numbers of well-stained, well-preserved intact cells for evaluation
- if cellular, are cells mainly inflammatory or non-inflammatory
how do you discern blood contamination from hemorrhage in cytology specimens?
- true hemorrhage can occur secondary to trauma, coagulopathy, or any other hemorrhagic process
- cytologic findings with hemorrhage:
- erythrophagia (by macrophages trying to ingest RBCs within 24 hours of hemorrhage)
- red cell breakdown products greater than 24 hours post hemorrhage:
-hemosiderin pigment (granular to globular, dark blue to black)
-hematoidin crystals (rhomboid, yellow to organe) - no platelets unless peracute hemorrhage
describe blood contribution to samples in terms of inflammatory cells (3)
- blood contains leukocytes (inflam cells) so whenever you see blood you should :
-imagine a normal blood smear, or compare with current CBC data and ask: are the number of inflam cells proportional to the amount of blood present? - if yes: leukocytes are likely blood derived
- if no: leukocytes could be increased due to inflammation
what types of inflammatory cells can be observed in cytology samples?
- neutrophils:
-degenerate (poofy, puffy cheetos bc nucleus is swollen) or non-degenerate (crunchy cheetos): not to be confused with toxic changes!
-degenerate changes occur in tissue often due to presence of IC bacteria, indicates septic inflammation - macrophages/histiocytes: +/- multi-nucleated giant cells
-if macrophagic: large mononuclear cells, rounded to ovoid nucleus, lots of cytoplasm that can be vacuolated
-can eat other cells (cytophagia) - lymphoid cells:
-lymphocytes (small, med, large), plasma cells
-if lymphocytic: should be mostly small lymphocytes (smaller than a neutrophil) +/- plasma cells and a few intermediate and large lymphocytes - eosinophils: +/- mast cells
-increased/eosinophilic if >10% eosinophils +/- mast cells
sum up inflammation on cytology
- determining the predominant cell type can help generate differentials and guide diagnostic/therapeutic plan
- absence of visible organism does not rule out infectious process
-based on clinical suspicions, pursue ancillary diagnostics (PCR, culture, serology) - degenerate change DOES NOT EQUAL toxic change
- inflammation does not necessarily rule out concurrent neoplasia
how do you classify neoplasia as epithelial, mesenchymal, or round cell?
epithelial tissue:
-contains epidermis, epithelium, glands, and parenchymal tissue
-will appear clustered on cytology, cuboidal to columnar polygonal to rounded with distinct cell borders with cell-cell junctions
-use context to determine neoplasia versus not: if predominant cells in a mass lesion suggests proliferation, but would expect more in like a skin impression; also if no longer look how they SHOULD, can indicate neoplastic process
mesenchymal:
-connective tissue: bone, cartilage, muscle, blood vessels, fat
-look like individualized cells (pile of puppies), but may aggregate +/- be mixed with pink extracellular matrix material
-fusiform to spindled appearance with tapered, indistinct cell borders
round cell (lymph!):
-small, intermediate, or large cells should look like skittles!
–multicentric large cell lymphoma is easier to diagnose!
-if granular, are T or NK cell in origin
-species, location, and immunophenotype determine prognosis
what are the types of round cell tumors? LYMPH
Lymphoma
(Y) Transmissible Venereal Tumor (TVT)
Mast cell tumor or Melanoma
Plasma cell tumor
Histiocytoma
describe the cytologic appearance of mast cell (round cell) tumors
- variable numbers and sizes of purple granules
- +/- concurrent eosinophils, reactive fibroblasts
- location and histopathologic grade determine prognosis
describe the cytologic appearance of TVT round cell tumor
transmissible venereal tumor in the angogenital region and face/nose; round cells with small, clear, hole punch vacuoles, can treat with chemo and not common in US
what are the general features of malignant neoplasia?
- nuclear features:
-anisokaryosis
-karyomegaly
-high nuclear to cytoplasm ration
-nuclear molding/spooning
-nultinucleation
-prominent, multiple, or angular nucleoli
-coarse/open chromatin
-mitotic figures - cellular features:
-anisocytosis
pleomorphism
describe cytologic appearance of histiocytoma (round cell) tumors
- typically seen in younger dogs as button lesions
- spontaneously regress due to lymphocyte infiltration
- fried egg with classic light blue cytoplasmic background
describe general cytologic appearance of melanoma (round cell) tumors
- can look round, epithelial, or mesenchymal
- need histopathology to determine benign versus malignant
- degree of pigmentation and location determine prognosis
- melanin likes to group together like epi cells
