新冠病毒病2019（COVID-19）是由严重急性呼吸综合征冠状病毒2（SARS-CoV-2）引起的感染，全球范围内包括日本受灾。这一COVID-19大流行已经改变了世界各地的生活方式。为了防止感染的传播，开发了多种COVID-19疫苗并建议接种。虽然这些疫苗的安全性和有效性已经得到证明，但是会出现一些不同频率的各种不良反应。毛发球乳头瘤是一种良性的皮下肿瘤。毛发球乳头瘤的成因不明，但是外部刺激可能是毛发球乳头瘤的部分原因。在此，我们报道了一例COVID-19疫苗接种后发生毛发球乳头瘤的罕见病例。在疫苗接种部位出现结节性病变的鉴别诊断中，应该将毛发球乳头瘤列入考虑范围，包括COVID-19疫苗的接种部位。

The coronavirus disease 2019 (COVID-19), which is an infection caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), spread worldwide including Japan. This COVID-19 pandemic has changed the way of life around the world. To prevent the spread of infection, several COVID-19 vaccines were rapidly developed and their vaccination is recommended. While safety and effectiveness of these vaccines have been shown, various adverse reactions occur with a certain frequency. Pilomatricoma is a benign subcutaneous tumor. Cause of pilomatricoma is unclear, however, an external insult could be a cause of part of pilomatricoma. Herein, we report a rare case of pilomatricoma after COVID-19 vaccination. Pilomatricoma should be included in the differential diagnoses of nodular lesions arising after vaccination sites, including the COVID-19 vaccine.