Inflammatory
cells are usually neutrophils, eosinophils, macrophages,
lymphocytes, plasma cells.
 |
| Pyoderma |
 |
| Pyoderma |
 |
| Eosinophilic plaque in a cat |
 |
| Interdigital granuloma in a dog |
Non-inflammatory
cells:
- Epithelial cells: tend to
exfoliate in high numbers are often present in cohesive clusters and sheets.
Individual cells are round, cuboidal or polygonal. Most epithelial cells have
well-defined cell borders. We see them on a regular basis in the inflammatory
preparations, where they are admixed with bacteria, fungi and inflammatory
cells. In non-neoplastic tumours we find them often in inclusion type cysts or
cystic epithelial tumours. They should be evaluated for criteria of malignancy.
 |
| Normal epidermal cells by layers |
 |
| Squamous cell carcinoma |
 |
| Basal cell tumor |
|
|
- Mesenchymal cells (spindle cells): Tissue cells tend to exfoliate
in low numbers and are present in loose aggregates or groups. The cells are
usually spindle shaped but can appear more ovoid and plump. If these cells are contained in an
inflammatory exudate they can become reactive and can mimic pleomorph neoplastic
cells. Usually this is seen in granulation tissue. However, a high number of
spindle-shaped cells are indicative of neoplasia. The origin is very difficult
to detect, they can arise form adipose, fibrous, vessel, neural etc. tissue.
 |
| Lipoma |
 |
| Liposarcoma |
 |
| Spindle cell tumor of soft tissue origin |
-
Round-cells: Round-cell lesions tend to
exfoliate readily, although cells can be fragile, requiring gentle preparation
for cytology. Cells are discrete with well-defined cell borders. Common cells
of this category include lymphocytes, histiocytes, mast cells, and plasma
cells, as well as cells of transmissible venereal tumors.
 |
| Histiocytoma |
 |
| Plasmacytoma |
 |
| Mast cell tumor |
 |
| Lymphoma |
 |
| Melanocytoma |
