Page 115 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

er 8
Chapt
102

VetBooks.ir Pearls and Pitfalls
A less common benign adenoma arising from the sebaceous glands is the sebaceous duct
•
adenoma. This is composed of a predominance of ducts (>50%) with a smaller propor-
tion of secretory sebocytes and reserve cells. The ducts often contain keratin and occa-
sionally sebum. Upon aspiration, these may exfoliate variable numbers of anucleated
squamous epithelial cells, sebocytes and cuboidal to columnar ductal cells.
• Cytologically, sebaceous adenoma cannot be distinguished from nodular sebaceous
hyperplasia. This does not have any clinical implication, as they are both benign lesions
that carry a good prognosis.
• The cytological differentiation between sebaceous epithelioma and a well-differentiated
sebaceous carcinoma can be very challenging. However, whilst epithelioma is relatively
common, sebaceous carcinoma is a rare tumour.
• On the eyelids, there are modified sebaceous glands called Meibomian glands. Adenomas
arising from the Meibomian glands are cytologically similar to the classical sebaceous
adenomas described above.

Fig. 8.18. Dog. Sebaceous adenoma. Mature sebocytes arranged in a cohesive cluster. Wright-Giemsa.