Page 114 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

Epithelial Tumours
101
• Sebaceous epithelioma:
• The tumour is composed of a predominance of reserve cells with a few sebocytes and
VetBooks.ir • ducts.
The aspirates often yield relatively large cohesive clusters of cuboidal reserve epithelial
cells admixed with small clusters of mature sebocytes. The reserve epithelial cells often
outnumber the mature sebaceous epithelial cells.
• Nuclei are small, dense and central, often with inconspicuous nucleoli.
• The cytoplasm is scant and pale to moderately basophilic. It occasionally contains low
numbers of variably sized (but often small) clear vacuoles.
• Anisokaryosis and anisocytosis are minimal. The N:C ratio is high.
• Sebaceous carcinoma:
• Cellularity is variable, usually high.
• Background: lightly to moderately basophilic and finely granular. It can contain vari-
ably sized punctate clear vacuoles.
• The aspirates are composed of variably sized, cohesive clusters of cuboidal epithelial cells.
Admixed with these cells, there might be low numbers of well-differentiated sebocytes.
• Nuclei are round, medium-large and with a finely stippled chromatin. Nucleoli are
variably visible.
• The cytoplasm is scant to moderate and moderately basophilic. It can contain variably
sized clear vacuoles.
• Anisokaryosis, anisocytosis and degree of pleomorphism are variable.
• Cell crowding is frequent. Nuclear moulding is occasionally observed.
• Mitotic figures can be found.

Differential diagnoses
• Sebaceous adenoma:
• Sebaceous hyperplasia
• Fibroadnexal hamartoma
• Sebaceous epithelioma and carcinoma:
• Liposarcoma
• Clear cell adnexal carcinoma