Feline Injection-Site Sarcoma

Abstract

Feline injection-site sarcoma (FISS) is an aggressive tumor believed to arise from the proliferation of fibroblasts and myofibroblasts in areas of chronic inflammation, particularly at sites of injection. Local recurrence is frequent after surgical excision. Gelatinases (MMP-2 and MMP-9) and their inhibitor (TIMP-2) are endopeptidases pivotal in extracellular matrix remodeling and therefore in tumor invasiveness. The aim of this study was to investigate the immunohistochemical expression of MMP-2, MMP-9, and TIMP-2 in FISS to assess their usefulness as prognostic factors. Size, soft tissue sarcoma (STS) grading system, depth of infiltration, surgical margins, and Ki-67 index were evaluated as additional prognostic markers. Twenty-four cases of primary FISS were classified according to clinical follow-up as nonrecurrent (NR, n = 14; 58.3%) and recurrent (R, n = 10; 41.7%). MMP-2, MMP-9, and TIMP-2 were variably expressed in the FISS examined, confirming their role in tumor invasiveness, yet they did not show significant differences between the R and NR groups. These results could be due to different tumor stages or to the multiple activities of these enzymes, not limited to ECM remodeling. The immunohistochemical expression of these enzymes considered alone does not seem to be useful as a prognostic marker. STS grading system, depth of infiltration, surgical margins, and Ki-67 index did not relate to recurrence. Instead, the size of the tumor, measured after formalin fixation, with an optimal cutoff of 3.75 cm (accuracy = 86%; P < .05), and the mitotic count, with an optimal cutoff of 20 mitoses/10 HPF (accuracy = 80%; P < .05), could be evaluated as useful prognostic markers.

Evaluation of leukocyte counts and neutrophil‐to‐lymphocyte ratio as predictors of local recurrence of feline injection site sarcoma after curative intent surgery

“…11,13,19 Although other variables, such as size and location of the tumour, expertise of the surgeon, recurrent tumours, p53 expression, mitotic count and differentiation, have been proposed as predictors of LR, there is still no consensus on which factors other than completeness of excision should be taken into account to predict prognosis. 8,13,15,20,21 Hence, readily available and accurate variables that can aid in identifying cats at higher risk of LR are desirable to improve oncological management of these patients.…”

Canine, feline, and equine corneal vascular neoplasia: A retrospective study (2007‐2015)

“…The presence of a chronic inflammatory microenvironment has been implicated in the development of multiple tumor types in multiple species. These include vaccine‐associated sarcoma in cats, post‐traumatic ocular sarcoma in cats, small cell epitheliotropic lymphoma in the gastrointestinal tract of cats with chronic inflammatory bowel disease, urothelial and vascular urinary bladder tumors in cattle with chronic bracken fern ingestion, Spirocerca lupi infection‐associated esophageal fibrosarcoma in dogs, and corneal squamous cell carcinoma associated with chronic inflammation and topical steroid/immune‐suppressive drug administration in dogs …”

CT angiography and MRI imaging features do not predict the tumor type and grade of feline injection site sarcoma

“…Feline injection site sarcomas (FISS) represent 15% of feline skin masses, are mesenchymal in origin, regionally invasive, and have a low rate of distant metastasis . Feline injection site sarcomas occur at sites of vaccination, microchip placement, and injection of drugs .…”

“…The prognosis of cats with FISS depends on the mass histopathological features such as the presence of peritumoral projections, peritumoral inflammation, tumor necrosis, infiltrative lymphocytes, and intracellular macrophage cellular aggregates . Recently, the histological grading scheme for canine soft tissue sarcomas has been applied to FISS with grading criteria based on cellular differentiation, mass necrosis, infiltrative depth, and mitotic rate . However, previous reports suggest the histological grade and patient prognosis are unassociated .…”

“…9,15,16 Recently, the histological grading scheme for canine soft tissue sarcomas has been applied to FISS with grading criteria based on cellular differentiation, mass necrosis, infiltrative depth, and mitotic rate. 3,7,9,13,14 However, previous reports suggest the histological grade and patient prognosis are unassociated. 4,7,9,15,17 Therefore, grading of FISS with the canine soft tissue sarcoma scheme may or may not be clinically informative.…”