Feline injection site sarcomas (FISS) are aggressive, with high recurrence and rarely metastasising. The objective of this study was to evaluate, by immunohistochemistry, the expression of oestrogen (ER) and progesterone (PR) receptors in FISS and correlate them with clinical and histopathological aspects. This was a retrospective study with 51 cases of FISS. Immunohistochemistry was performed to detect vimentin, ER, PR and Ki67 expression. Clinical, histopathological and immunohistochemical characteristics were predictor variables and the expression of ER and PR were the dependent ones. Twenty-eight (55%) of the 51 FISS cases were female and 23 (45%) male with 10.7 ± 4.2 years and median tumour size of 3 cm (2.0-5.4). The trunk was the most affected site, with 38 cases (84%). Histological grade III was observed in 57% of the cases, considering differentiation score, necrosis and mitotic index. ER expression, positive in 64% of cases, was associated with the mitotic index (P = .05) and degree of pleomorphism (P = .04). PR was not associated with the variables and 63% of cases were negative for this receptor. Thus, ER expression can affect tumour growth. The knowledge on the FISS hormonal expression is important to clarify the pathophysiological mechanisms. Further studies are needed to predict the value of ER expression in the prognosis of FISS.

中文翻译：

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猫注射部位肉瘤的激素受体表达、临床和组织病理学分析

猫注射部位肉瘤 (FISS) 具有侵袭性，复发率高且很少转移。本研究的目的是通过免疫组织化学评估 FISS 中雌激素 (ER) 和孕激素 (PR) 受体的表达，并将它们与临床和组织病理学方面相关联。这是一项包含 51 例 FISS 的回顾性研究。进行免疫组织化学以检测波形蛋白、ER、PR和Ki67的表达。临床、组织病理学和免疫组化特征是预测变量，ER和PR的表达是依赖变量。51 例 FISS 病例中有 28 例 (55%) 为女性，23 例 (45%) 为男性，年龄 10.7 ± 4.2 岁，中位肿瘤大小为 3 cm (2.0-5.4)。躯干是受影响最大的部位，有 38 例（84%）。在 57% 的病例中观察到组织学 III 级，考虑分化评分、坏死和有丝分裂指数。ER 表达在 64% 的病例中呈阳性，与有丝分裂指数相关（P  = .05) 和多形性程度 ( P  = .04)。PR 与变量无关，63% 的病例对该受体呈阴性。因此，ER表达可以影响肿瘤生长。FISS激素表达的知识对于阐明病理生理机制很重要。需要进一步的研究来预测ER表达在FISS预后中的价值。