为了评估COVID-19疫苗接种后不同时间范围内腋窝淋巴结疾病的发生率和淋巴结的病理特征（即增大和定性特征），本研究获得了机构审查委员会的批准。本研究对象为2021年7月至10月进行乳腺摄影和乳腺超声检查的女性。研究收集了关于COVID-19疫苗和感染的信息。已知的转移性淋巴结病例被排除在研究范围之外。根据接种疫苗后和影像检查之间的时间进行分组： < 6周；7-8周；9-10周；11-12周； > 12周。腋窝淋巴结的评估采用超声技术进行。进行了描述性统计分析。p < 0.05被认为是显著的。共纳入了285名女性。其中大多数接种了Moderna疫苗（n = 175，占61.4%）。63/285例患者具有乳腺癌病史（占22.1%）。13/17例（76.5%）先前感染COVID-19的患者没有乳腺癌病史，而4/17例患者有乳腺癌病史（p < .001）。41/285名女性显示出淋巴结疾病，年龄明显较年轻（46.9 ± 11.6岁）与具有边缘病变（54.0 ± 11.9岁）或没有淋巴结疾病（57.3 ± 11.9岁）的女性对比（p < .001）。淋巴结疾病和边缘病变在接种Moderna疫苗的女性中和接种疫苗后 < 6周的患者子组中更为常见（p < 0.001）。最常见的病理特征是皮质增厚，其次是脂肪山丘的完全或部分消失。接种疫苗后12周内出现淋巴结疾病是一种常见现象，尤其是在年轻女性和接种Moderna疫苗后，不需要进一步评估。© 2023意大利医学放射学学会。

To assess the incidence of axillary lymphadenopathy over established time ranges after COVID-19 vaccination and lymph node pathologic features (i.e. size increase and qualitative characteristics) in subjects undergoing axillary evaluation during a breast imaging examination.The institutional review board approved this prospective study.women undergoing mammography and breast ultrasound between July and October 2021; information about the COVID-19 vaccine and infection, if any.known metastatic lymphadenopathy. Participants were divided into 5 subgroups according to time between vaccine and imaging: < 6 weeks; 7-8 weeks; 9-10 weeks; 11-12 weeks; > 12 weeks. Evaluation of axillary lymph nodes was performed with ultrasound. Descriptive statistical analysis was performed. p < 0.05 was considered significant.A total of 285 women were included. Most of the patients underwent Moderna vaccine (n = 175, 61.4%). 63/285 patients had a previous history of breast cancer (22.1%). 13/17 (76.5%) patients with previous COVID-19 infection had no previous history of cancer, whereas 4/17 had a previous history of cancer (p < .001). 41/285 (14.4%) women showed lymphadenopathy, and they were significantly younger (46.9 ± 11.6 years) than women with borderline (54.0 ± 11.9 years) or no lymphadenopathy (57.3 ± 11.9 years) (p < .001). Lymphadenopathy and borderline lymphadenopathy were more frequently observed in the Moderna-vaccinated women and in the subgroup of patients evaluated < 6 weeks after vaccination (p < 0.001). The most common pathologic feature was cortical thickening, followed by complete or partial effacement of fatty hilum.A lymphadenopathy within 12 weeks after vaccination is a common finding particularly in younger women and after Moderna vaccine and no further assessment should be required.© 2023. Italian Society of Medical Radiology.