An Unusual Case of Systemic Lymphadenopathy - Kimura's Disease.

Background: Kimura's disease (KD) is a rare, chronic inflammatory disease. Clinically, subcutaneous nodules of the head and neck are typical manifestations, often accompanied by local lymphadenopathy or salivary gland enlargement, but there is also systemic damage, such as kidney involvement. Due to the lack of specific markers and imaging examination is not specific, it is difficult to clinically diagnose accurately and can be easy to misdiagnose. The treatment of KD is still not standardized and overtreatment can affect the quality of life. Case Presentation: The case of a 26-year-old man complaining of chest pain with self-conscious progressive lymphadenopathy after receiving Pfizer BioNTech COVID-19 vaccine for more than 1 month is presented. Eosinophil levels were normal and IgE elevated and the final diagnosis of KD was eventually confirmed by lymph node biopsy, which revealed lymphadenopathy with extensive eosinophilic infiltration in the right neck. Treatment was prednisone combined with methotrexate, resulting in satisfactory control. Conclusion: This case demonstrates that that Kimura disease can involve systemic lymphadenopathy, not only in the head and face or regional lymphadenopathy, suggested that KD should be excluded in patients with systemic lymphadenopathy. The current patient's response to treatment suggested that corticosteroid combined with disease-modifying antirheumatic drugs (DENARDs) was a promising treatment for KD patients with systemic damage. It is worth noting that the mechanism of immunity in the pathogenesis of KD still needs to be further studied.