Cytological Examination
This technique is good for detecting the presence of skin parasites, bacteria, yeasts, fungi, inflammatory cells, or abnormal skin cells.
The skin may bleed a little after being scraped, but the wound is minor (no more than a scratch) and usually does not cause any discomfort..
With a relatively small investment of time and resources, cytology can often provide a definitive diagnosis.
Howver if a diagnosis is not made from cytology, it often is still helpful to categorize the condition, which then helps your veterinarian decide what further steps are needed to reach a definitive diagnosis..
Dog Cytology involves taking a swab of the vaginal wall and examining the cells under a microscope.
The timing of the swab depends on the individual dog's estrus cycle.
But (as mentioned above), it is typically done multiple times throughout the cycle to monitor changes and pinpoint the optimal time for breeding..
The most important type among cells with cytoplasmic granules is the mast cell, given that mast cell tumors are common in dogs.
These are medium-sized cells with round nuclei.
With Romanowsky stains, the granules are dark blue or purple, small (about the size of bacteria), and usually found in large numbers in the cytoplasm.
See Table 3 for a list of cytologic characteristics.
Histiocytomas (Figure 8) are only identified in dogs and commonly diagnosed in dogs less than 4 years of age. 1 The neoplastic cell is a Langerhans cell or epidermal dendritic cell 9 and often resolves on its own.
Cytology is most often used to diagnose the nature of lumps and bumps found on the surface of the body.
However, cytology can also be used to evaluate internal organs, body fluids, effusions, and surfaces of the body.
Different techniques are employed to collect cells depending on the type of sample needed.
Cytology of a canine MCT showing poorly staining mast cells; scattered red blood cells and cells with segmented nuclei are seen in the background (Diff Quik stain; magnification, 20×).
FIGURE 6.
Cytology from the same sample as Figure 5, stained with a Wright-Giemsa stain; the mast cell granules now can easily be seen.
