Kikuchi-Fujimoto disease, simultaneously diagnosed with systemic lupus erythematosus in an Arabic female: an agonizing combination.

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare, benign condition affecting young Oriental-Asian females. It is characterized by fever and tender cervical lymphadenopathy with an unclear aetiology, and in most longitudinal reviews, KFD occurs before systemic lupus erythematosus (SLE). Herein, the case of a 28-year-old Kuwaiti female without any relevant past medical history, who was simultaneously diagnosed with KFD and SLE following an Ebstein-Barr virus infection, is reported. The patient was treated with oral prednisolone, hydroxychloroquine, cyclosporin, and belimumab and her response was clinically and biochemically favourable. Although KFD is prevalent in Asian populations, it may affect all races. Early diagnosis of KFD is difficult, particularly when simultaneously diagnosed with SLE, but crucial to preventing inappropriate therapy. Clinicians need to know about this rare disease, especially when patients present with fever and swollen lymph nodes, due to a risk of misdiagnosis with tuberculosis or lymphoma, as these are more often thought to be the cause of such symptoms.

Distinguishing Kikuchi-Fujimoto disease from lymphoma in patients by clinical and PET/CT features.

To develop a scheme for distinguishing Kikuchi-Fujimoto disease (KFD) from lymphoma in patients presenting enlarged lymph nodes (LNs) predominantly on the upper side of the diaphragm. From November 2015 to August 2023, 32 KFD patients and 38 lymphoma patients were pathologically confirmed and enrolled in this retrospectively study. Clinical and 18F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) features were collected. When comparing those PET/CT parameters, we set 5 models with different research objects: (1) all affected LNs; (2) the 5 largest affected LNs in terms of maximum diameter; (3) the 5 largest affected LNs in terms of maximum standard uptake values (SUVmax); (4) the largest affected LNs in terms of maximum diameter; (5) the largest affected LNs in terms of SUVmax. Compared to lymphoma patients, KFD patients were younger; and with higher incidence of fever, arthralgia, abnormal serum white blood cell, lactate dehydrogenase (LDH) and splenomegaly; lower incidence of affected LNs perinodal infiltration, necrosis and conglomeration; more affected LNs in Head and Neck nodes (particularly in level II) and Axillary in KFD (P ˂ .05). PET/CT parameters presented as various difference in each model. Finally, 11 clinical and PET/CT features (age ≤ 34, with fever, arthralgia, abnormal white blood cell, abnormal LDH, and without node necrosis and node conglomeration have a score of 2 each; splenomegaly, perinodal infiltration, median maximum diameter ≤ 20.5 and median SUVmax ≤ 7.1 of affected LNs in model 2 have score of 1 each) were selected as scheme items for distinguishing KFD from lymphoma. Individuals who have a total score > 8, meet the criteria for KFD. Sensitivity and specificity were high: 86.8% (95% CI: 71.9%, 95.5%) and 96.9% (95% CI: 83.7%, 99.5%), AUC = 0.975 (95% CI: 90.5%, 99.6%), respectively. It can effectively distinguish KFD from lymphoma by clinical and PET/CT parameters.

Kikuchi-Fujimoto disease evolves into lupus encephalopathy characterized by venous sinus thrombosis: a case report.

Kikuchi-Fujimoto disease (KFD) is a benign, self-limiting illness that can progress to systemic lupus erythematosus (SLE) in approximately 30% of cases. Neurological injuries can occur in both diseases, albeit with distinct presentations. Venous sinus thrombosis is a serious cerebrovascular complication in patients with neuropsychiatric SLE but is rarely observed in patients with KFD. The involvement of various antibodies, particularly antiphospholipid antibodies, can cause vascular endothelial cell injury, resulting in focal cerebral ischemia and intracranial vascular embolism in SLE. However, there are cases in which thrombotic pathology occurs without antiphospholipid antibody positivity, attributed to vascular lesions. In this report, we present a case of KFD and lupus encephalopathy featuring cerebral venous sinus thrombosis, despite the patient being negative for antiphospholipid antibody. We also conducted a comparative analysis of C3 and C4 levels in cerebrospinal fluid (CSF) and peripheral blood, along with the protein ratio in CSF and serum, to elucidate the pathological changes and characteristics of lupus encephalopathy.

Kikuchi-Fujimoto disease associated with a flare-up of a leukocytoclastic vasculitis: A rare case report and review of literature.

RATIONALE: Kikuchi-Fujimoto disease (KFD) also known as histiocytic necrotizing lymphadenopathy is an exceedingly rare cause of cervical lymphadenopathy, commonly accompanied by systemic symptoms such as fever, fatigue, night sweats, myalgia, skin rash. PATIENT CONCERNS: In this paper, we report the case of a 22-year-old female patient who experienced a flare-up of leukocytoclastic vasculitis that was complicated by the appearance of a cervical lymph node with dysphagia, fever and nausea. DIAGNOSIS: Infectious and autoimmune workup came back negative. INTERVENTIONS: Excisional lymph node biopsy was done and the pathology results were consistent with histiocytic necrotizing lymphadenitis in keeping with Kikuchi-Fujimoto disease. OUTCOMES: Patient improved on intravenous corticosteroids and was discharged on per os prednisone. Six month follow-up shows complete resolution of her symptoms. LESSONS: KFD should be ruled out in patients with autoimmune or inflammatory diseases who develop lymphadenopathies.

[Recurrent lymphadenitis was Kikuchi-Fujimoto disease]. / Lymfadenit som mystiskt återkom var Kikuchi­Fujimotos sjukdom.

Kikuchi-Fujimoto disease, or histiocytic necrotizing lymphadenitis, is in most cases a benign disease which affects lymph nodes in the cervical region. Cervical adenopathy and fever are the most common symptoms, and young adults are mostly affected. Lymph node biopsy is the mode of diagnosis with demonstration of paracortical areas of apoptotic necrosis with abundant karyorrhectic debris and a proliferation of histiocytes, plasmacytoid dendritic cells, and CD8+ T cells in the absence of neutrophils. In most cases, the disease is self-limiting but it can be recurrent or evolve to SLE. Treatment varies from symptomatic to more systemic with cortisone and intravenous immunoglobulin.

Kikuchi disease in acute leukaemia: a distinct clinical syndrome with HLA association.

AIMS: To report the clinicopathological features of Kikuchi disease in patients with acute leukaemia, emphasising similarities among cases. METHODS AND RESULTS: In a cohort of 454 Kikuchi disease patients, we identified three cases of concurrent acute leukaemia. These patients shared similar clinical traits, with Kikuchi disease emerging approximately a month after induction chemotherapy onset, featuring neck-region lymphadenopathy. Notably, two patients were middle-aged, deviating from the typical age distribution of Kikuchi disease. Histologically, these cases aligned with typical Kikuchi disease. Negative immunohistochemical stains (CD34, CD117, ERG, TdT) indicated the absence of extramedullary leukaemic infiltration. Herpes simplex virus immunohistochemical staining was also negative. Significantly, a human leucocyte antigen (HLA) association was observed in these three cases. HLA-B*15:01, C*04:01, and DRB1*04:06 were more prevalent in these patients compared to the general population (compared with three independent control cohorts: Taiwanese Han Chinese (n = 504), Tzu Chi Taiwanese bone marrow donors (n = 364) and Hong Kong Chinese (n = 5266)). CONCLUSIONS: Our study underscores the unique link between Kikuchi disease and acute leukaemia, characterised by specific features and HLA associations. This underlines Kikuchi disease as a possible differential diagnosis in pertinent clinical scenarios. Furthermore, this syndrome offers insights into postchemotherapy immunology in acute leukaemia, enhancing comprehension.

Kikuchi-Fujimoto disease, a rare benign disease with atypical histomorphology: more than meets the eye.

Kikuchi-Fujimoto disease (KFD) is a benign self-limiting condition primarily affecting young females. It usually presents with fever and cervical lymphadenopathy of unknown aetiology with a preponderance of the Asian population. Histopathology is critical in making an accurate diagnosis. While the typical microscopic features include paracortical necrosis with debris, histiocytosis with immunoblasts, and absent neutrophils, rarely, KFD can show atypical features like marked immunoblastic proliferation mimicking lymphoma, demonstrate vasculitis mimicking lupus erythematosus, etc. The diagnosis is extremely challenging if such features occur in cases with generalised lymphadenopathy, which is infrequent in KFD. The study aims to describe the morphological, clinical, and immunohistochemical features of KFD and determine the frequency of the atypical features. We also analysed the subtle histological and immunohistochemical features that aid in the diagnosis of atypical cases. Cases reported as KFD over a period of 6 years were retrieved from the archives of histopathology. The morphological features were categorised as typical and atypical. In the atypical cases, the features that aided in the correct diagnosis of KFD were analysed. Out of the 42 cases evaluated, 23.9% (n=10) had generalised lymphadenopathy; 57.2% (n=24) were women with a median age of 25 years. Leukopenia was observed in 42% (n=13) of patients. Typical features were present in 76.2% (n=32) cases and 23.8% (n=10) presented with atypical features. Eight cases were antinuclear antibody-positive. Atypical features included five (50%) cases with vasculitis and panniculitis, and three (30%) cases with large, atypical cells for which immunohistochemistry (IHC) was performed. In two of these cases, the patent sinuses, absence of neutrophils, and IHC with CD68 aided the diagnosis. There is an overlap of clinical and histopathological features between KFD and malignant lymphomas and systemic lupus erythematosus. Given the fact that the atypical features (23.8%) are not rare occurrences in KFD, correlations with clinical findings and ancillary studies are essential to avoid misdiagnosis and inadvertent therapy.

A rare co-existence of histiocytic necrotizing lymphadenitis with metastatic papillary thyroid carcinoma and review of the literature.

Histiocytic necrotizing lymphadenitis (HNL) is a benign, self-limiting disease that is rare clinically. The coexistence of HNL and tumor is rarer. We report a male patient who was preoperatively diagnosed with papillary thyroid carcinoma with cervical lymph nodes metastasis, and the postoperative pathological examination showed histiocytic necrotizing lymphadenitis combined with metastatic papillary thyroid carcinoma in the same single lymph node. More interestingly, Epstein‒Barr virus was positive in these lymph nodes by in situ hybridization. This may suggest a trigger for the coexistence of the two diseases.

Clinical features of histiocytic necrotizing lymphadenitis in children.

Due to its nonspecific clinical characteristics, histiocytic necrotizing lymphadenitis (HNL) is often misdiagnosed as a suppurative cervical lymphadenitis and lymphoma. Thus, this study aimed to investigate the clinical characteristics of HNL in pediatric patients. We retrospectively identified 61 patients with histopathologically confirmed HNL. Clinical and laboratory data, including age, sex, clinical manifestations, laboratory investigations, histological discoveries, treatment, and outcomes, were collected from the medical records to determine associations with extracervical lymph node (LN) involvement. The mean age of patients was 9.7 ± 2.8 years (range, 1.5-14.0 years), and the male-to-female ratio was 2.2:1. The most common systemic symptom was fever in all patients. The median pre-admission and total durations of fever were 13.0 (interquartile range [IQR]: 9.0-22.5 days) and 22.0 days (IQR: 17.0-33.0 days), respectively. Patients with temporary fever (< 2 weeks) had a higher peak temperature and were more likely to undergo LN biopsy after admission than those with a prolonged fever (≥ 2 weeks). Multivariate analysis revealed that peak temperature ≥ 40 °C was significantly associated with a longer fever duration (P = 0.023). Laboratory values showed leukopenia (68.9%), which presented more frequently in solitary cervical LNs than in extracervical LNs (82.4% vs. 52.9%, p = 0.027) in patients with prolonged fever. CONCLUSIONS: HNL is often misdiagnosed in older children with persistent fever and lymphadenopathy, leading to unnecessary diagnostic tests and evaluations, inappropriate antibiotic administration, and mismanagement. A multidisciplinary team, including primary care providers, rheumatologists, and pathologists, can improve patient outcomes by increasing their awareness of this rare condition. WHAT IS KNOWN: • Histiocytic necrotizing lymphadenitis (HNL) is characterized by fever, leukopenia, and neck lymphadenopathy with unknown etiology. • The lack of neutrophils or eosinophils in the histology, immunohistochemistry results help distinguish HNL from infectious causes. Although HNL is a self-limiting disease, antibiotics and steroid treatments were used inappropriately. WHAT IS NEW: • A fever peak ≥ 40 °C was associated with a longer fever duration in HNL patients. Leukopenia presented more frequently in solitary cervical lymph node (LNs) than in extracervical LNs inpatients with prolonged fever. • Steroids are not recommended as a routine treatment, however, in some severe or relapsing cases with persistent symptoms, prednisolone (5 mg twice a day for 2 days) or other steroids (an equivalent dose of prednisolone) responded favorably.

Kikuchi-Fujimoto's Disease: A Rare and Underdiagnosed Condition with Possible Renal Involvement.

Kikuchi-Fujimoto disease (KFD), or Histiocytic Necrotizing Lymphadenitis, is a rare disease, with worldwide distribution but is best known in Japan and South Asia. The most common feature is cervical lymphadenopathy, accompanied by tenderness or high fever, with night sweats, but it can also be asymptomatic or with a very wide range of symptoms. The diagnosis is histopathological, on excisional biopsy. The Kikuchi-Fujmoto disease can mimic lymphoma but also tuberculosis and some autoimmune diseases, or be associated with them. Nephrologists need to be aware of it, considering the potential renal involvement. The association with systemic lupus erythematosus (SLE) is the most frequent but not the only one. Early diagnosis of this disease can prevent unnecessary investigations and aggressive therapies.

Kikuchi-Fujimoto Disease Following COVID-19 Vaccination: Experience at a Population-Based Referral Center.

OBJECTIVES: Multiple case reports describe Kikuchi-Fujimoto disease (KFD) following COVID-19 vaccination, but the true nature of this phenomenon is unknown. The purpose of this study was to further assess the relationship between KFD and COVID-19 vaccination at the population level. METHODS: Confirmed KFD cases from January 2018 to April 2022 were identified from provincial pathology archives and analyzed in the context of vaccination statistics from public health resources. RESULTS: Our statistical models provide evidence of a temporal association between KFD and both antecedent COVID-19 vaccine administration as well as age-stratified vaccination rates. Eight new cases of plausible COVID-19 vaccine-associated KFD are presented, collectively exhibiting clinical and pathologic features that overlap substantially with those of idiopathic KFD. CONCLUSIONS: Our findings indicate that KFD is observed in association with COVID-19 vaccination and suggest that mechanistic studies are warranted.

A homozygous loss-of-function C1S mutation is associated with Kikuchi-Fujimoto disease.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a self-limited inflammatory disease of unknown pathogenesis. Familial cases have been described and defects in classical complement components C1q and C4 have been identified in some patients. MATERIAL AND METHODS: We describe genetic and immune investigations of a 16 years old Omani male, a product of consanguineous marriage, who presented with typical clinical and histological features of KFD. RESULTS: We identified a novel homozygous single base deletion in C1S (c.330del; p. Phe110LeufsTer23) resulting in a defect in the classical complement pathway. The patient was negative for all serological markers of SLE. In contrast, two female siblings (also homozygous for the C1S mutation), one has autoimmune thyroid disease (Hashimoto thyroiditis) and a positive ANA and the other sibling has serology consistent with SLE. CONCLUSION: We report the first association between C1s deficiency and KFD.

Clinicopathologic Analysis of Kikuchi-Fujimoto Disease and Etiologic Exploration Using Metagenomic Next-Generation Sequencing.

CONTEXT.­: Kikuchi-Fujimoto lymphadenitis, also known as Kikuchi-Fujimoto disease (KFD), is a self-limited lymphoproliferative disease, with no definitive causative agent confirmed by traditional methods. OBJECTIVES.­: To further explore the clinicopathologic features of KFD and clarify related pathogenic factors. DESIGN.­: A retrospective analysis was performed in a collection of KFD cases to review the clinical and histopathologic features, and metagenomic next-generation sequencing (mNGS) was used in 64 formalin-fixed, paraffin-embedded (FFPE) tissues from patients with KFD. RESULTS.­: One hundred five of the 170 patients with KFD (61.8%) were female; 10 patients had autoimmune diseases. Four pathologic subtypes were classified: necrotic (45.9%, 78 of 170), phagocytic (32.4%, 55 of 170), proliferative (17.1%, 29 of 170), and xanthomatous (4.7%, 8 of 170). Patients younger than 40 years with unilateral cervical lymphadenopathy and small vessel fibrinous degeneration accounted for significant differences among the 4 pathologic subtypes (P < .05). Among 64 patients with KFD, 9 had detectable bacterial or viral DNA-of 6 bacterial cases, 1 involved Chlamydia psittaci; while of 3 viral cases, 1 involved human beta herpesvirus 6B and 2 involved Epstein-Barr virus. No significant relationships were found between the pathologic subtypes and specific pathogens. CONCLUSIONS.­: Only a small proportion of patients with KFD had autoimmune diseases or infections from specific pathogens, suggesting that KFD is likely a reactive lesion of lymph nodes to various circumstances. To our knowledge, this is the first and the largest study to detect pathogens with the use of mNGS on FFPE samples in KFD. Our study also further confirms that mNGS can be used on FFPE samples to detect potentially infectious agents in clinical settings.

Clinical scoring approach for detection of histiocytic necrotising lymphadenitis in adults.

BACKGROUND: Histiocytic necrotising lymphadenitis (HNL) is rare and can be easily ignored. AIMS: To summarise the characteristics of HNL and find a simple scoring approach to detect HNL in adult patients. METHODS: Adult patients with lymphadenopathy diagnosed by lymph node biopsy were enrolled. Chi-squared test and t-test were used to determine the significant variables. The cut-off values and scores assigned to each factor were performed by receiver operating characteristic (ROC) curves and coefficients in the logistic regression respectively. The performance of the scoring system was evaluated by ROC curves. RESULTS: There were 32 HNL cases and 1162 other cases in the present study. These features, including age, the frequency of presentations of fever, cervical and painful lymph nodes, decrease of white blood cells (WBC), ratio of neutrophil to WBC (N ratio) and elevated lactate dehydrogenase (LDH), were different between patients with HNL and other diseases. Based on the multivariate analysis, the scoring approach was defined as follows: score = 3 (fever) + 2 (cervical lymphadenopathy) + 2 (decreased WBC) + 1 (decreased N ratio) + 2 (elevated LDH). The cut-off was score 4. This approach performed will detect HNL with an area under the curve of 0.889. CONCLUSION: The present study suggests that the novel scoring approach we put forward might be useful to detect HNL in adult patients though further studies are needed.

Kikuchi-Fujimoto Disease: A Distinct Pathological Entity but also an "Overlap" Autoimmune Syndrome: A Systematic Review.

BACKGROUND: The association between KFD and autoimmune diseases, not only with systemic lupus erythematosus, has been repeatedly described. OBJECTIVE: The aim of this review is to evaluate whether an overlap syndrome is present between KFD and autoimmune diseases, whether there is a chronological and a casual relationship between the pathologies. METHODS: The databases used for the overlap case search were Medline and Embase from which we extrapolated the studies of interest. The search queries used were: Kikuchi-Fujimoto Syndrome and juvenile idiopathic arthritis or systemic lupus erythematosus or Systemic Sclerosis or Antiphospholipid Syndrome or Sjogren's Syndrome. All study types were considered (n = 103). RESULTS: Total number of included studies are 43. We have shown that there is an "overlap" syndrome between KFD and other autoimmune diseases. The chronology of disease onset was variable; autoimmune disease may be "preceding" (n = 11 cases) or "simultaneous" (n = 20 cases) or "post" (n = 8 cases). Kikuchi-Fujimoto Syndrome. Also, the autoimmune disease can present with a complete clinical picture or only with the presence of autoantibodies. CONCLUSION: the different pathologies associated with KFD with different chronologies would suggest that there is an alteration of the immune system that allows the pathologies to occur in different temporal relationships.

Case report: Kikuchi-Fujimoto disease: unveiling a case of recurrent fever and enlarged cervical lymph nodes in a young female patient with a literature review of the immune mechanism.

The inflammatory response to viral infection is an important component of the antiviral response, a process that involves the activation and proliferation of CD8+ T, CD4+ T, and dendritic cells; thus, viral infection disrupts the immune homeostasis of the organism, leading to an increased release of inflammatory factors. Kikuchi-Fujimoto disease (KFD) is an inflammatory self-limited disorder of unknown etiology, and it is generally believed that the pathogenesis of this disease includes two aspects: viral infection and autoimmune response. Various immune cells, such as CD8+ T lymphocytes, CD4+ T lymphocytes, and CD123+ plasmacytoid dendritic cells, as well as the cytokines they induce and secrete, such as interferons, interleukins, and tumor necrosis factors, play a crucial role in the pathogenesis of KFD. In this article, we present a case study of a young female patient from China who exhibited typical symptoms of lymph node inflammation and fever. The diagnosis of KFD was confirmed through a lymph node biopsy. She presented with elevated ESR, IL-6, and IFN-γ. Viral markers showed elevated IgG and IgM of cytomegalovirus (CMV) and elevated IgG of Epstein-Barr virus (EBV), while changes occurred in the CD4+ T and CD8+ T cell counts. Eventually, the patient achieved disease relief through steroid treatment. Based on these findings, we conducted a comprehensive review of the involvement of viral infection-induced inflammatory response processes and autoimmunity in the pathogenesis of Kikuchi-Fujimoto disease.

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.

Kikuchi-Fujimoto disease as the initial manifestation of systemic lupus erythematosus complicated with macrophage activation syndrome: two case reports and a review of literature.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a self-limiting and benign disease characterized by cervical lymphadenopathy and fever. Although KFD should be made differentially diagnosed from infectious, autoimmune, and malignant diseases, it sometimes occurs in patients with systemic lupus erythematosus (SLE) and can be complicated with macrophage activation syndrome (MAS). However, it is rare that KFD is the initial manifestation of SLE and to be complicated with MAS. CASE PRESENTATION: A 9.6-year-old girl presented with high-grade fever, double-side cervical lymphadenopathy with mild pain of one week, leukopenia, alopecia, and rash on the cheek. During hospitalization, laboratory investigations showed positive antinuclear antibody (ANA), low complement 3 (C3), and low complement 4 (C4). Imaging investigations showed pleural and pericardial effusion. A 10.3-year-old girl presented with intermittent high-grade fever, double-sided cervical lymphadenopathy with obvious pain of 1-month duration, and discoid lesion on the cheek. During hospitalization, laboratory investigations showed positive ANA, leukopenia, thrombocytopenia, anemia with positive Coombs' test, low C3, and positive Smith antibodies. Both cases were diagnosed with KFD using lymph node biopsy, simultaneously fulfilling the diagnostic criteria of SLE. Subsequently, the two girls became complicated with MAS, followed by interstitial lung disease and neuropsychiatric lupus, respectively. Both patients benefited from high-dose methylprednisolone pulse therapy combined with intravenous cyclophosphamide. CONCLUSIONS: More attention should be paid to differential diagnosis, especially SLE, in children diagnosed with KFD. In addition, children with SLE who presented with KFD as the initial manifestation seem to have a higher risk of developing MAS and experiencing organ involvement.

Kikuchi disease: An alternative diagnosis in patients with axillary lymphadenopathy.

Kikuchi-Fujimoto disease is a benign, self-limiting lymphohistiocytic disorder. Although this condition is uncommon in Spain, it must be considered in the differential diagnosis of patients with lymphadenopathies. Although the classical presentation of Kikuchi-Fujimoto disease usually involves the cervical lymph nodes, there are also atypical presentations, such as in the case presented here in which the patient had isolated axillary involvement.

Kikuchi-Fujimoto disease can present as delayed lymphadenopathy after COVID-19 vaccination.

Following COVID-19 vaccination, ipsilateral axillary and cervical lymphadenopathy may occur, called vaccine-related hypermetabolic lymphadenopathy, which is considered reactive lymphadenopathy. We report here a case of Kikuchi-Fujimoto disease, which occurred three months after vaccination with COVID-19 vaccine. The patient had cervical and axillary lymph node enlargement and a short-term fever that resolved spontaneously after the first and second vaccines. On the 90th day after the first vaccination, the patient developed a high fever and pathologically diagnosed necrotizing lymphadenitis in the axilla, which was diagnosed as Kikuchi-Fujimoto disease. Gallium scintigraphy showed localized swelling and strong uptake in the ipsilateral axilla. It implies the possibility of Kikuchi-Fujimoto Disease in axillary drainage lymph nodes in association with COVID-19 vaccine. Although only a few cases have been reported so far, this case is novel because of its later onset and diagnosis based on pathological and gallium scintigraphy imaging findings.