BackgroundKikuchi-Fujimoto disease (KFD) is a rare, benign, and self-limited disease that presents with cervical lymphadenopathy and systemic symptoms. Histologic evaluation is often necessary to differentiate KFD from other entities.MethodsElectronic medical records and diagnostic material were reviewed for 14 children diagnosed with KFD and 6 children diagnosed with infectious mononucleosis (IM) from 2013-2021. Four cases of KFD were further characterized using targeted DNA-based next-generation sequencing.ResultsSystemic symptoms were present in 86% (n = 12/14) of KFD patients, the most common being fever. Laboratory values worrisome for malignancy included cytopenia(s) (n = 9/12), elevated ESR and/or CRP (n = 9/12), elevated ferritin (n = 7/7), and elevated LDH (n = 7/10). Histologically, lymph nodes showed characteristic necrotic foci without neutrophils surrounded by MPO+ “crescentic” histiocytes. Immunoblasts and CD123+ plasmacytoid dendritic cells (pDCs) were also increased surrounding the necrosis. IM lymph nodes showed similar features when necrosis was present but increases in pDCs were patchy and rare neutrophils were seen in the necrotic foci. Molecular analysis of 4 KFD cases did not identify pathogenic variants.ConclusionWhile the signs/symptoms of KFD are worrisome, there are pathologic features that help differentiate it from potential mimics. We did not identify characteristic molecular features to aid in the work-up of these cases.

中文翻译：

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恶性模仿者：菊池-藤本病在儿科人群中的特征

背景菊池-藤本病（KFD）是一种罕见的良性自限性疾病，表现为颈部淋巴结肿大和全身症状。组织学评估通常是区分 KFD 与其他实体所必需的。方法审查了 2013-2021 年诊断为 KFD 的 14 名儿童和 6 名诊断为传染性单核细胞增多症 (IM) 的儿童的电子病历和诊断材料。使用基于靶向 DNA 的二代测序进一步表征了 4 例 KFD。结果 86% (n = 12/14) 的 KFD 患者出现全身症状，最常见的是发烧。令人担忧的恶性肿瘤实验室值包括血细胞减少（n = 9/12）、ESR 和/或 CRP 升高（n = 9/12）、铁蛋白升高（n = 7/7）和 LDH 升高（n = 7/ 10）。组织学上，淋巴结显示特征性坏死灶，无中性粒细胞，周围有 MPO+“新月体”组织细胞。坏死周围的免疫母细胞和 CD123+ 浆细胞样树突状细胞 (pDC) 也增加。当存在坏死时，IM 淋巴结表现出相似的特征，但 pDC 的增加呈片状，并且在坏死病灶中观察到罕见的中性粒细胞。对 4 例 KFD 病例的分子分析未发现致病变异。结论虽然 KFD 的体征/症状令人担忧，但有一些病理特征有助于将其与潜在的类似物区分开来。我们没有确定特征分子特征来帮助处理这些病例。当存在坏死时，IM 淋巴结表现出相似的特征，但 pDC 的增加呈片状，并且在坏死病灶中观察到罕见的中性粒细胞。对 4 例 KFD 病例的分子分析未发现致病变异。结论虽然 KFD 的体征/症状令人担忧，但有一些病理特征有助于将其与潜在的类似物区分开来。我们没有确定特征分子特征来帮助处理这些病例。当存在坏死时，IM 淋巴结表现出相似的特征，但 pDC 的增加呈片状，并且在坏死病灶中观察到罕见的中性粒细胞。对 4 例 KFD 病例的分子分析未发现致病变异。结论虽然 KFD 的体征/症状令人担忧，但有一些病理特征有助于将其与潜在的类似物区分开来。我们没有确定特征分子特征来帮助处理这些病例。