Histomorphological and immunophenotypic characterizationof feline injection site-associated sarcoma
Pereira, Sílvia TeixeiraGamba, Conrado OliveiraHorta, Rodrigo SantosCunha, Rúbia Monteiro de CastroLavalle, Gleidice EuniceCassali, Geovanni DantasAraújo, Roberto Baracat de
Background: Feline Injection Site-Associated Sarcoma (FISS) is a mesenchymal neoplasia of aggressive behavior thatdevelops in sites where vaccine or drugs were administered. FISS is clinically characterized by the appearance of asolitary firm nodule or a diffuse mass, adhered to tissues, in regions associated to vaccine or drug applications. Despitelow prevalence, tumor recurrence rates can reach 80%. FISS present more aggressive histological characteristics whencompared to sarcomas not associated to injection sites. The aim of this paper is to contribute towards the understandingof the biological behavior of FISS.Materials, Methods & Results: Sixteen samples of FISS were analyzed. Fibrosarcomas were the most frequent histological subtype (62.5%). Malignant peripheral nerve sheath tumor was diagnosed in 18.75% cases. Ten (62.5%) FISS wereclassified as grade II; 4/16 (25%) grade I, and 2/16 (12.5%) grade III. Cox-2 overexpression occurred in 3/16 (18.75%)samples, with positive correlation between Cox-2 expression and cellularity (r = 0.696, P = 0.003). Mitotic index lowerthan 9 events was found in 11/16 (68.7%) samples and between 10 and 19 mitotic events in 5/16 (31.3%) cases. MeanKi-67 expression was 2.39 ± 2.48%. FISS characterized as fibrosarcomas presented longer overall survival (median 545days) than other histological subtypes (median 130.5 days) [P = 0.01].Discussion: Patients with FISS generally present with larger nodules than those with sarcomas not associated to injections,suggesting a challenge for pet owners to note subcutaneous tumors in the interscapular region, in addition to the aggressivebiological behavior of FISS. The influence of size on prognosis remains controversial. An association between histologicgrade and the development of metastasis has been observed, with patients with grade III FISS associated with an increasein the metastatic rate. The present study did not find a correlation between overall survival...(AU)
Texto completo