Page 61 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

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6.7 Xanthoma
VetBooks.ir Deposition in the dermis of cholesterol, triglyceride and/or phospholipids causing a granuloma-

tous inflammation.

Clinical features

• Rare in cats and very rare in dogs.
• It is the result of abnormal plasma concentrations of cholesterol, triglycerides or lipo-
proteins, which may deposit into tissues, including skin.
• It may be secondary to high-fat diet feeding, diabetes mellitus or idiopathic
hyperlip idaemia. In the cat, it has also been associated with secondary hyperlipidaemia
due to glucocorticoid or progesterone therapy. Trauma may play a role in the
formation of xanthoma.
• It presents as multiple pale yellow to white papules, plaques or nodules, often oozing
material upon aspiration.
• In cats, it occurs more often in the preauricular and periorbital region and, to a lesser
extent, elsewhere on the head, pinnae, neck, legs and bony prominences. Similar loca-
tions and ventrum are seen in dogs.
• Lesions may regress spontaneously with successful management of the primary
disease, when present.

Cytological features
• Cellularity is generally adequate.
• Background: variably haemodiluted. Cholesterol crystals may be seen.
• Variable numbers of macrophages with abundant foamy cytoplasm containing frequent
clear distinct vacuoles, compatible with lipid material. Bi- and multinucleated cells are
commonly seen.
• Other inflammatory cell types may also be present, in particular small lymphocytes and
occasionally neutrophils and eosinophils.

Differential diagnosis
Panniculitis