Page 125 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

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Pearls and Pitfalls
VetBooks.ir Clinical differential diagnoses for these tumours include:
Cats: inflammatory polyps arising from the middle ear and extending to the external ear
•
canal. Upon aspiration, inflammatory polyps may exfoliate either large polygonal or oval
epithelial cells arranged singly or in small clusters and/or cells with respiratory epithelial
differentiation. The latter are columnar with round, basal nuclei and a moderate amount
of light basophilic cytoplasm, sometimes with apical cilia. Cells may contain small gran-
ules of secretory material. Concurrent inflammation is common.
• Dogs: hyperplastic polypoid otitis externa.
• The diagnosis of well-differentiated carcinoma lacking significant pleomorphism is made
on histopathology when invasion of the adjacent tissues and numbers of mitoses are
observed.

Fig. 8.27. Cat. Ceruminous gland carcinoma. Mildly disorganized clusters of ceruminous epithelial cells. They dis-
play crowding and have a high N:C ratio. Nuclei have a coarse chromatin and one to multiple prominent nucleoli.
Wright-Giemsa.