Page 82 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

Cysts, Tumour-like Lesions and Response to Tissue Injury
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• Inflammatory response of variable degree. Inflammatory cells are mostly macrophages, with
low numbers of giant multinucleated cells and occasionally neutrophils. Neutrophils are more
VetBooks.ir • frequent in ulcerated lesions. Small lymphocytes and plasma cells may also be seen.
Amorphous purple material (likely necrotic tissue) can be observed.
• Fibroblasts may be present, especially in calcinosis circumscripta.

Differential diagnoses
• Tissue necrosis
• Granulomatous inflammation of other aetiology

Pearls and Pitfalls
• Cytochemical stains (von Kossa and Alizarin red S) can be used to confirm the presence
of calcium deposits and may be required in hypercellular samples where the inflammatory
component prevails and the crystals are hardly detectable on regular microscopy.
• The addition of immersion oil to the slide generally causes a characteristic change in the
colour of the background.

Fig. 7.10. Dog. Calcinosis. Appearance of a stained cytological smear of calcinosis. Note the characteristic chalky
lavender colour.