Clinical features and recurrence predictors of histiocytic necrotizing lymphadenitis in Chinese children.

OBJECTIVES: To characterize the clinical features and to identify the predictors of recurrence of histiocytic necrotizing lymphadenitis (HNL) in Chinese children. STUDY DESIGN: This study retrospectively analyzed the clinical characteristics, laboratory and pathological findings, and recurrence status of children diagnosed with HNL at a single center in China from January 2018 to May 2023. Logistic regression analysis was employed to identify predictors of HNL recurrence. RESULTS: 181 Chinese children with histopathologically confirmed HNL were enrolled (121 males and 60 females). The mean age was 9.3 ± 2.9 years. The most prominent clinical features were fever (98.9%) and cervical lymphadenopathy (98.3%). Aseptic meningitis was the most frequent complication (38.5%), while hemophagocytic lymphohistiocytosis and autoimmune disease were rare (1.7% and 1.2%, respectively). Recurrence occurred in 12.7% of patients. Erythrocyte sedimentation rate (> 30 mm/h) was the significant predictors of HNL recurrence, with odds ratios of 6.107, respectively. CONCLUSION: Our study demonstrates that fever and cervical lymphadenopathy are the most frequent clinical manifestations of HNL in Chinese children, which often coexist with aseptic meningitis. HNL patients with risk factors require follow-up for recurrence.

[Clinical characteristics and treatment in adults and children with histiocytic necroti-zing lymphadenitis].

OBJECTIVE: To analyze the clinical data of histiocytic necrotizing lymphadenitis(HNL), comparing the similarities and differences between children and adults, to deepen the understanding of the disease by clinical physicians, and to improve diagnostic rate and reduce misdiagnosis and mistreatment. METHODS: The clinical data of hospitalized patients with histiocytic necrotizing lymphadenitis diagnosed by biopsy from January 2010 to August 2023 in Peking University First Hospital were collec-ted, and the clinical features, laboratory examinations, pathological features, treatments with antibiotics and glucocorticoids, and prognosis of histiocytic necrotic lymphadenitis were analyzed. Grouped based on age, the differences of clinical characteristics, laboratory tests, treatment, and prognosis between the children group (< 16 years old) and the adult group (≥16 years old) were compared. RESULTS: Among the 81 enrolled patients, there were 42 males and 39 females. The median age was 21(14, 29) years, the median duration of disease was 20.0(13.0, 30.0) days, and the median length of hospital stay was 13.0 (10.0, 15.0) days. The first symptoms were fever, lymphadenopathy, and both. All the patients had enlarged lymph nodes with different parts and sizes, 96.3% (78 of 81) of the patients had cervical lymphadenopathy, 50.6% (41 of 81) had bilateral cervical lymphadenopathy, 55.6% (45 of 81) had supraclavicular, axillary or inguinal lymphadenopathy, and the median lymph node diameter was 20.0(20.0, 30.0) mm. Only one patient had no fever, the other 80 patients had fever, the median peak body temperature was 39.0(38.0, 39.8) ℃. Accompanying symptoms: rash (8.6%, 7/81), fatigue (34.6%, 28/81), night sweating (8.6%, 7/81), chills (25.3%, 25/81), muscle soreness (13.6%, 11/81), and joint pain (6.2%, 5/81). There were 17 cases (21.0%, 17/81) of hepatosplenomegaly, of which 12 cases (70.6%, 12/17) were splenomegaly. 68.8%(55/80) of patients had a decrease in white blood cell (WBC) count, with 47.5%(38/80)increased in lymphocyte(LY)proportion, 53.4%(39/73) increased in high-sensitivity C-reactive protein(CRP), 79.2%(57/72) increased in erythrocyte sedimentation rate(ESR), 22.2%(18/81) increased in alanine transaminase(ALT), 27.2%(22/81) elevated in aspartate transaminase(AST), and 81.6%(62/76) elevated in lactate dehydrogenase(LDH). All the 81 patients underwent lymph node biopsy, and 77.8%(63/81) of the patients showed that most of the structures in the lymph nodes were destroyed or disappeared, and 16.0%(13/81) of the lymph nodes were still in existence, hyperplasia and normal lymph node were 1.2%(1/81) respectively, and 3.7%(3/81) had normal lymph node structures. Immunohistochemical staining was performed in 67 cases. The percentages of CD3+ and CD68(KP1)+ were respectively 97.0%(65/67), and MPO+ were 94.0%(63/67). In the study, 51 patients (63.0%, 51/81) were treated with glucocorticoid therapy after diagnosis. The median time for temperature to return to normal was 1.0(1.0, 4.0) days after glucocorticoid therapy. when the glucocorticoid treatment worked best, the body temperature could drop to normal on the same day. There were significant differences in length of stay, predisposing factors, chills, the rate of increase in high-sensitivity CRP, antibiotic and glucocorticoid treatment between the adults and children groups (P < 0.05). CONCLUSION: In clinical practice, if there are cases with unexplained fever, superficial lymph node enlargement, and reduced white blood cells as clinical characteristics, and general antibiotics treatment is ineffective, histiocytic necrotic lymphadenitis should be considered. Lymph node biopsy should be performed as early as possible to clarify the diagnosis, reduce misdiagnosis and mistreatment, and symptomatic treatment should be the main treatment. Glucocorticoids therapy has a definite therapeutic effect.

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.

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.

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 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.

Unilateral gluteal myositis as a unique presentation in mesenteric Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease (KFD) is a self-limiting disease, characterised by fever and cervical lymphadenopathy. Lymphadenopathy without cervical lymph node involvement is rare and may mimic lymphoma. Although KFD can be associated with extranodal involvement, muscle involvement has not been reported. Herein, we report a novel case of unilateral gluteal myositis associated with mesenteric KFD in a patient who presented with persistent fever and right hip pain. Radiological imaging revealed an inflammatory lesion on the right gluteal muscle and multiple enlarged abdominal lymph nodes. No cervical lymphadenopathy was observed. A mesenteric lymph node biopsy was performed, and the histopathological findings led to a diagnosis of KFD. By day 29, the patient's body temperature gradually returned to normal without any therapeutic intervention. Follow-up radiological imaging showed resolution of the gluteal lesion and a significant decrease in abdominal lymph node size. Considering the clinical course, the unilateral myositis may have developed as an extranodal involvement of KFD. Even if the clinical findings appear unrelated to those of KFD, a differential diagnosis that includes KFD should be considered in patients with unknown origin of fever.

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.