CYTOLOGIC GRADING OF CANINE AND FELINE SPINDLE-CELL SARCOMAS OF SOFT TISSUES AND ITS CORRELATION WITH HISTOLOGIC GRADING

LXVIII CONVEGNO SISVET, XI CONVEGNO AIPVET E XII CONVEGNO SIRA 214 CYTOLOGIC GRADING OF CANINE AND FELINE SPINDLE-CELL SARCOMAS OF SOFT TISSUES AND ITS CORRELATION WITH HISTOLOGIC GRADING Millanta F.*[1], Asproni P.[1], Romano E.[1], Aquino G.[2], Poli A.[1] [1]Department of Veterinary Science, University of Pisa ~ Pisa, [2]"Ardenza" Veterinary Hospital ~ Livorno The grading of soft tissue spindle cell sarcomas (STSCS) is considered more useful than histologic histotype to assign a specific therapy and determine the prognosis in humans (Enzinger et al., 2001). Histologic grading is considered an important prognostic factor in canine STSCS as it may predict the onset of local recurrence and metastatic potential. In human pathology and in the veterinary practice, fine needle aspiration aspiration cytology (FNAC) of soft tissue mass lesions can be an accurate and minimally invasive method for the initial pathologic diagnosis of soft tissue masses. The aim of our study was to assess the utility and the accuracy of the cytologic grading on FNAC smears, in comparison to the histologic grading in STSCS Over a period of 2 years (2009-2011) 33 cases of cytologically diagnosed STSCS (20 canine and 13 feline) with a following histological diagnosis were retrospectively separately reviewed. The FNAC smears were graded without prior knowledge of the histologic grade, using the scheme proposed by Weir et al., (1999), which is a three-tier system based on nuclear atypia, nuclear overlap, mitosis, and necrosis. The corresponding histological sections were graded using the Coindre et al.,(1988) criteria in a blind fashion. The degree of concordance was established using the Cohen’s K coefficient. (Palmer et al., 2001). In the canine SCSTS there was an overall cytologic and histologic concordance for grading in 12/20 cases (60%). The concordance was observed in 4/8 (50%) cases of histologic grade 1, in 8/12 (67%) cases of grade 2, and in 0 cases of grade 3. In the feline species the concordance was 11/13 cases (85%). The concordance was observed in 5/6 (83%) tumors of histologic grade 1, in 4/4 (100%) tumors of grade 2, and in 2/3 (66.6%) cases of grade 3. The overall concordance in the entire study population of canine and feline STSCS was 70%. The gradewise concordance was 65% in grade 1 cases, 75% in grade 2 cases, and 66% in grade 3 cases. The overall concordance is quite similar to that reported in human literature. Although a wider population is required to strengthen our findings, these results suggest that cytologic grading of STSCS obtained by FNA may be a useful tool for therapeutic approaches and as a prognostic indicator. Coindre KM, Nguyen BB, Bonichon F, et al. Cancer. 1988; 61:2305-2309 Enzinger FM, Weiss SW, Goldblum JR. Soft tissue tumors, 4th ed. St. Louis, Mosby; 2001: 10-13. Palmer HE, Mukunyadzi P, Culbreth W, Thomas JR. Diagn Citopathol. 2001; 24(5):307-316 Weir MM, Rosemberg AE, Bell DA. Am J Clin Pathol, 1999; 112:784-790 diagnostic cytopathology, small animal oncology cytologic grading, soft tissue sarcoma, dog and cat