Nonocular melanocytic neoplasia is considered uncommon in cats yet is routinely encountered in diagnostic pathology and recognized to exhibit a wide variation in biological behavior. Accurate prediction of clinical outcomes is challenging with no widely recognized prognostic criteria. Signalment and tumor location were retrospectively evaluated in 324 cats diagnosed with nonocular melanocytic neoplasia. Histologic features were described in 141 neoplasms and outcome data were available in 79 cases. Immunohistochemistry using Melan-A, PNL-2, cyclooxygenase 2 (COX-2), and E-cadherin was performed in a subset (n = 24). Multivariate analysis identified tumor site, mitotic count, and the presence of intratumoral necrosis to be independent predictors of tumor-related death. On the basis of these findings, we propose a novel histologic grading scheme in which nonocular melanocytic neoplasms involving the lips, oral or nasal mucosa, or nasal planum are considered high grade if they fulfill 1 or both of the following criteria: at least 4 mitoses in 10 high-power fields (HPF) or presence of intratumoral necrosis; those arising elsewhere are considered high grade if they fulfill both of the above criteria. Of 79 tumors with outcome data, 43 (54%) were low grade and 36 (46%) were high grade. The grading system had an 80% sensitivity and 92% specificity for predicting tumor-related death in this population of cats. Median survival for cats with low-grade tumors was not reached, and the median survival was 90 days for those with a high-grade tumor. PNL-2 and Melan-A were sensitive markers for feline nonocular melanocytic neoplasia, and although not significantly associated with prognosis, a large proportion expressed COX-2, suggesting a potential therapeutic role for COX-2 inhibitors.

中文翻译：

---

猫非黑素细胞瘤样增生：组织学分类方案的表征和提议，以更准确地预测临床结果。

非猫黑素细胞瘤形成被认为在猫中不常见，但在诊断病理学中经常遇到，并被认为在生物学行为上表现出很大的差异。没有广泛认可的预后标准，对临床结果的准确预测具有挑战性。回顾性分析了324只诊断为非眼黑素细胞瘤的猫的信号和肿瘤位置。在141例肿瘤中描述了组织学特征，在79例患者中可获得结局数据。使用Melan-A，PNL-2，环氧合酶2（COX-2）和E-钙粘蛋白的免疫组织化学在一个子集中进行（n = 24）。多变量分析确定肿瘤部位，有丝分裂计数和肿瘤内坏死的存在是肿瘤相关死亡的独立预测因子。根据这些发现，我们提出了一种新颖的组织学分级方案，其中涉及嘴唇，口腔或鼻粘膜或鼻腔平面的非眼黑素细胞瘤如果满足以下一项或两项标准，则被认为是高等级的：10个高倍视野中至少有4个有丝分裂HPF）或肿瘤内坏死的存在；如果满足以上两个条件，则在其他地方产生的那些将被视为高等级。在具有结果数据的79个肿瘤中，低度恶性肿瘤43例（54％），高恶性肿瘤36例（46％）。该分级系统在预测这一猫群中与肿瘤相关的死亡方面具有80％的敏感性和92％的特异性。患有低度肿瘤的猫的中位生存期未达到，而具有高度肿瘤的猫的中位生存期为90天。PNL-2和Melan-A是猫非眼黑素细胞瘤形成的敏感标志物，