Purpose: Cat scratch disease (CSD) is an infectious disorder caused primarily by the bacterium Bartonella henselae (B. henselae). Immunohistochemistry (IHC) and Warthin-Starry silver stain (WS) are considered to be indispensable to diagnose CSD in combination with morphologic characteristics. In this study, we retrieved and reviewed 46 cases of paraffin-embedded lymphadenitis with histologic and/or clinical suspicion of CSD between 2014 and 2018, and detected B. henselae by IHC and WS, respectively, and evaluated the application significance of IHC and WS for the detection of B. henselae and validated their values in the pathologic diagnosis of CSD. Materials and Methods: B. henselae was detected by IHC and WS; validation of 2 methods for detecting B. henselae was evaluated by sensitivity, specificity, false-positive rate, false-negative rate, precision, negative predictive value, and agreement rate. Results: Microscopically, suppurative granulomas and/or multiple stellate microabscesses were observed in the accessory cortex of lymph nodes, especially near the subcapsule. Our results showed that 80.4% (37/46) of cases were positive for B. henselae by IHC, manifesting mainly punctuate, granular, or linear to outline the shape of bacteria. However, the positive rate of B. henselae by the WS method was 52.2% (24/46). There was a significant difference between IHC and WS (P=0.023). Moreover, a positive percentage of B. henselae was 97.8% (45/46), which was detected by the combined application of IHC and WS. The combination of IHC and WS exhibited high sensitivity (97.8%) and good agreement rate (86.5%). Conclusion: The combined application of the IHC and WS method may have important clinical advantages, which is with the highest sensitivity and agreement rate for pathologic diagnosis of CSD.

中文翻译：

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免疫组化联合Warthin-Starry银染色在猫抓病病理诊断中的应用

目的：猫抓病 (CSD) 是一种主要由亨氏巴尔通体 (B. henselae) 细菌引起的传染病。免疫组织化学 (IHC) 和 Warthin-Starry 银染色 (WS) 结合形态学特征被认为是诊断 CSD 必不可少的。本研究检索回顾了2014-2018年间组织学和/或临床怀疑CSD的46例石蜡包埋淋巴结炎病例，分别采用IHC和WS检测B. henselae，评价IHC和WS的应用意义用于检测 B. henselae 并验证它们在 CSD 病理诊断中的价值。材料与方法：IHC和WS检测B. henselae；2 种检测 B. henselae 方法的验证通过敏感性、特异性、假阳性率、假阴性率、准确率、阴性预测值和一致率。结果：镜下可见淋巴结副皮层，尤其是包膜下有化脓性肉芽肿和/或多发性星状微脓肿。我们的结果表明，80.4% (37/46) 的病例 IHC 呈 B. henselae 阳性，主要表现为点状、颗粒状或线状以勾勒出细菌的形状。然而，WS方法对B. henselae的阳性率为52.2%（24/46）。IHC 和 WS 之间存在显着差异（P=0.023）。此外，通过 IHC 和 WS 的联合应用检测到 B. henselae 的阳性百分比为 97.8% (45/46)。IHC 和 WS 的组合表现出高灵敏度 (97.8%) 和良好的一致性率 (86.5%)。结论：