Page 105 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

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• Concurrent inflammation is common, especially if the keratin is exposed to the surrounding
tissues. Mixed bacteria can also be seen.
VetBooks.ir • Malignant trichoepithelioma may show variable features of malignancy, such as hyperchro-
matic nuclei, increased anisokaryosis and anisocytosis and mitotic figures. Areas of necrosis
may be present.

Differential diagnoses
• Follicular cyst (if no cuboidal epithelial cells are seen)
• Infundibular keratinizing achantoma
• Pilomatricoma (if only ghost cells are seen)
• Ductal adenoma of the sweat glands

Pearls and Pitfalls
In well-differentiated forms, the histological diagnosis of malignancy may be based only on
the presence of infiltrative growth or vascular invasion, therefore cytology may be unable to
recognize these lesions as malignant.

Fig. 8.12. Dog. Trichoepithelioma. There are cuboidal epithelial cells in dense cohesive clusters (right) and anucle-
ated squamous epithelial cells (left). Wright-Giemsa.