Page 164 - Differential Diagnosis in Small Animal Cytology, The Skin and Subcutis

Mesenchymal Tumours and Other Neoplasms
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Pearls and Pitfalls
VetBooks.ir • The cytological distinction between injection-site sarcoma and severe reactive fibroplasia
can be difficult. Reactive fibroblasts arising in granulation tissue are often pleomorphic
and can be easily mistaken for malignant neoplastic cells.
• The Vaccine Associated Feline Sarcoma Task Force (VAFSTF) recommends that every
mass that: (i) persists for more than 3 months; (ii) is larger than 2 cm; and (iii) increases
in size 1 month after injection should be biopsied (3-2-1 rule). Incisional biopsy is pre-
ferred to Tru-cut biopsy, since the tumour can be heterogeneous and can be misdiagnosed
as a granuloma for small tissue samples. Given the highly infiltrative nature of this tu-
mour, advanced imaging (CT scan) must be performed prior to surgical excision.

Further reading

Martano, M., Morello, E. and Buracco, P. (2011) Feline injection-site sarcoma: past, present and future perspec-
tives. Veterinary Journal 188, 136–141.