Page 158 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

Mesenchymal Tumours and Other Neoplasms
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Variants
VetBooks.ir Different variants of haemangiosarcoma have been described in the literature and include epithe-
lioid, solar-induced and anaplastic forms. Differentiation is made on histopathology; however,
some variants may be suspected on cytology, such as the epithelioid haemangiosarcoma.

• Epithelioid variant
Neoplastic endothelial cells resemble epithelial cells (hence epithelioid) for appearance and
arrangement. They occasionally contain intracytoplasmic clear vacuoles.

Differential diagnosis
Sarcoma of other origin

Pearls and Pitfalls
• Aspiration from cavitated areas of the mass can lead to excessive haemodilution of the
sample and inadequate nucleated cellularity. Sampling from solid areas of the mass may
increase the likelihood of harvesting neoplastic cells.
• Lymphangiosarcomas are neoplasms of the lymphatic vessels. They are uncommon
and may appear cytologically similar to haemangiosarcomas. These tumours often
arise in the subcutis of ventral midline and limbs and form poorly demarcated, some-
times oedematous masses. In cats, this form is also known as feline ventral abdominal
angiosarcoma.

Fig. 9.17. Dog. Haemangiosarcoma. Neoplastic cells show marked anisokaryosis, prominent and multiple nucleoli
and atypical mitoses. Wright-Giemsa.