Kikuchi-Fujimoto-like lymphadenopathy following COVID-19 vaccine: diagnosis and management.

A woman in her mid 40s presented for breast imaging after 1 week of painful and enlarged right axillary lymphadenopathy. She denied history of fever, weight loss, night sweats fatigue, cat scratch or other trauma. She received the second dose of Pfizer COVID-19 vaccine 3 months previously on the contralateral arm. A mammogram demonstrated a single, asymmetric, large and dense right axillary lymph node. Ultrasound confirmed a 2.5 cm lymph node with cortical thickening of 0.6 cm. Ultrasound-guided core biopsy showed necrotising lymphadenitis with associated aggregates of histiocytes and plasmacytoid dendritic cells. Potential causes of necrotising adenitis including Bartonella, tuberculosis, Epstein-Barr Virus, herpes simplex virus, systemic lupus erythematosus and lymphoma were excluded. In the absence of any identifiable infectious or autoimmune causes, and given the temporal relatedness with vaccine administration, it was determined that the Kikuchi-Fujimoto-like necrotising lymphadenitis was likely secondary to the COVID-19 vaccine. To date, there has been no casual association made between the COVID-19 vaccine and KFD necrotising lymphadenitis.

Kikuchi-Fujimoto disease following SARS-CoV-2 vaccination.

A previously healthy Japanese woman in her 20s was admitted to our hospital with a 2-week history of fever (39.0°C) and a 1-week history of painful cervical lymphadenopathy. The day before fever onset, she had received her first Pfizer-BioNTech SARS-CoV-2 vaccine in her left arm. She had previously been treated with empirical antibiotics with no improvement. Physical examination revealed painful lymphadenopathy in both posterior cervical regions. CT showed symmetrical lymphadenopathies in the neck, supraclavicular, axillary and inguinal regions as well as hepatosplenomegaly. We suspected lymphoma and performed a lymph node biopsy in the right inguinal region, which revealed necrotising histiocytic lymphadenitis. The patient was, therefore, diagnosed with Kikuchi-Fujimoto disease (KFD). She improved after the corticosteroid therapy. This report highlights the importance of including KFD as a differential diagnosis of lymphadenopathy after SARS-CoV-2 vaccination. Additionally, lymph node biopsy is helpful for diagnosing KFD because it rules out other entities.

Self-limiting COVID-19-associated Kikuchi-Fujimoto disease with heart involvement: case-based review.

BACKGROUND: The association between COVID-19 infection and the development of autoimmune diseases is currently unknown, but there are already reports presenting induction of different autoantibodies by SARS-CoV-2 infection. Kikuchi-Fuimoto disease (KFD) as a form of histiocytic necrotizing lymphadenitis of unknown origin. OBJECTIVE: Here we present a rare case of KFD with heart involvement after COVID-19 infection. To our best knowledge only a few cases of COVID-19-associated KFD were published so far. Based on presented case, we summarize the clinical course of KFD and its association with autoimmune diseases, as well we discuss the potential causes of perimyocarditis in this case. METHODS: We reviewed the literature regarding cases of "Kikuchi-Fujimoto disease (KFD)" and "COVID-19" and then "KFD" and "heart" or "myocarditis" by searching medical journal databases written in English in PubMed and Google Scholar. RESULTS: Only two cases of KFD after COVID infection have been described so far. CONCLUSION: SARS-CoV-2 infection can also be a new, potential causative agent of developing KFD.