Feline Vaccine-associated Fibrosarcoma: Morphologic Distinctions

Abstract

Forty-four primary feline vaccine-associated fibrosarcomas and 16 recurrences were examined histologically for detailed morphologic characterization with emphasis on tumor grade, presence of neoplastic multinucleated giant cells, presence and proportion of T and B lymphocytes within the tumor, and thin and intermediate filament contents of neoplastic and stromal cells. The microvascularity and proliferation rates of central and peripheral areas of the tumors were also quantified by computerized image analysis. For primary fibrosarcomas, 11 of 44 (25%) were grade I, 21 of 44 (47.7%) were grade II, and 12 of 44 (27.3%) were grade III. The recurrences followed a similar pattern: 4 of 16 (25%) were grade I, 8 of 16 (50%) were grade II, and 4 of 16 (25%) were grade III. A positive correlation was found between the presence of neoplastic multinucleated giant cells and tumor grade. These cells were present in 9 of 12 (75%) of grade III and none of the grade I tumors. Prominent peritumoral lymphoid aggregates or follicles were present in 59% of the tumors, and many contained high proportions of T lymphocytes, varying from 19 to 87%. All fibrosarcomas were immunoreactive for vimentin and 28 of 44 (64%) were reactive for alpha-smooth muscle actin. The actin-positive cells were either part of the tumor or formed a capsule around tumor nodules. The peripheral vascularity was significantly higher than the central vascular density but no difference was found in tumor cell proliferation rates between the two areas. Centrally located, fluid-filled micro- or macrocavitations were frequently observed in the large vaccine sarcomas and probably formed secondary to rapid tumor growth and central necrosis.

Feline vaccine-associated fibrosarcoma induced by aluminium compound in two cats: Short communication

“…VAFs were strongly positive for vimentin and negative for desmin intermediate filaments by immunohistochemistry (Couto et al, 2002) Acid solochrome azurin and aluminon methods have been used for the detection of aluminium in some types of human bone disease (Denton et al, 1984). This paper reports the histopathological characterisation and examination of two cases of feline VAF induced by an aluminium compound.…”

Description of a Feline Injection-Site Fibrosarcoma with Metastasis in the Cerebellum

“…As we observed in our subject, a follicular infi ltrate composed of lymphocytes and plasma cells can be identifi ed in the peripheral zone of FISSs [21,25]. The role of these lymphocytes in tumorigenesis and/or host response is unknown [26]. Another feature identifi ed in the tumoral masses of the presented cat were the neoplastic multinucleated giant cells, which are common in FISS.…”

“…Another feature identifi ed in the tumoral masses of the presented cat were the neoplastic multinucleated giant cells, which are common in FISS. Usually, they reveal a less differentiated tumor phenotype [26,27].…”

Role of inflammation/wound healing in feline oncogenesis: A commentary

“…Prominent or abundant inflammation was reportedly seen in 59.1% of vaccine-associated sarcomas in cats, consisting of peritumoral lymphoid aggregates or follicles and smaller numbers of macrophages (Couto et al 2002).…”

“…The location, magnitude and type of inflammatory cells present in feline vaccine-site sarcomas are also variable (Hendrick and Brooks 1994, Doddy et al 1996, Couto et al 2002. Prominent or abundant inflammation was reportedly seen in 59.1% of vaccine-associated sarcomas in cats, consisting of peritumoral lymphoid aggregates or follicles and smaller numbers of macrophages (Couto et al 2002).…”