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 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.

Encephalitis in Kikuchi-Fujimoto disease being immune-mediated.

INTRODUCTION: Histiocytic necrotizing lymphadenitis, also known as Kikuchi-Fujimoto disease, is a rare benign self-limiting inflammatory disease often seen in young adults. The main clinical features are fever with cervical lymphadenopathy. Neurological complications of Kikuchi-Fujimoto disease were occasionally reported although the specific pathogenesis was not clear. The condition could be severe when encephalitis coexists. METHODS: Here we reported a young case of Kikuchi-Fujimoto disease with subsequent severe autoimmune encephalitis. RESULTS: The symmetric striatal and limbic MRI lesions combined with psycho-cognitive, epileptic symptoms supported encephalitis. Tissue-based immunofluorescence revealed widely cytoplasmic fluorescence in rat cerebellar and hippocampal neurons, which provide evidence for immune-mediated encephalitis. The clinical outcome was satisfactory after immunosuppressive therapy with MRI lesions largely disappeared. CONCLUSION: The encephalitis complication of Kikuchi disease may be autoimmune and mediated by cytotoxic T cells.

Analysis of the clinical manifestations and 18F-FDG PET-CT findings in 40 patients with histiocytic necrotizing lymphadenitis.

ABSTRACT: Histiocytic necrotizing lymphadenitis (HNL) is a rare, benign, and self-limiting inflammatory disease that mainly involves the lymph nodes. There is a lack of large sample studies concerning the clinical manifestations and imaging features of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of HNL.The clinical symptoms, laboratory examination results, 18F-FDG PET/CT imaging features, and treatment outcome were investigated in this retrospective study.A total of 40 HNL patients were recruited. The onset age was between 14 and 65 years, with a median of 25 years. The white blood cell count was 3.9 (2.9, 7.1) × 109/L, C-reactive protein level was 20.2 (6.6, 63.8) mg/L, erythrocyte sedimentation rate was 29.0 (18.0,45.0) mm/h, and ferritin was 616.5 (205.6, 2118.1) ng/mL. An abnormal liver function was observed in 23 patients. 18F-FDG PET-CT showed that an abnormal lymph node metabolism was observed in 38 patients, among which the highest 18F-FDG maximal standard uptake value (SUVmax) of the lymph nodes ranged between 3.4 and 41.9; the nodes were mainly distributed in the neck and axilla regions. Meanwhile, a total of 2502 lymph nodes (721 lymph nodes with a short axis greater than 10 mm) were found in the 38 patients, including 1837 lymph nodes with an 18F-FDG SUVmax ≥ 2.5. The 18F-FDG SUVmax of the spleen ranged from 2.5 to 9.2 in 20 patients, while that of central and peripheral bone marrow ranged from 2.7 to 36.0 in 30 patients. After follow-up for an average period of 1 month, the symptoms improved after prednisone treatment.HNL often occurs in adolescents. Scanning with 18F-FDG PET/CT showed that most patients had multiple involved lymph nodes that were hypermetabolic, and only few lymph nodes are enlarged. Besides, the spleen or central and peripheral bone marrow could sometimes be hypermetabolic. Glucocorticoid treatment for the HNL patients is effective.

Positron emission tomography/computed tomography hypermetabolism of Kikuchi-Fujimoto disease mimicking malignant lymphoma: a case report and literature review.

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a benign, self-limiting inflammatory disorder of unknown etiology and pathogenesis. This report presents a rare case involving a man with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) hypermetabolism caused by KFD mimicking malignant lymphoma. The PET/CT maximum intensity projection showed multiple hypermetabolic lymphadenopathies and homogeneous FDG uptake in the bone marrow and spleen. Malignant lymphoma was initially suspected. The patient then underwent excision biopsy of one enlarged right cervical lymph node that was selected because it showed the highest FDG uptake in PET/CT, and examination of this biopsy specimen confirmed the diagnosis of KFD. PET/CT is useful for assessing the general condition of patients and can help to select lymph nodes for excision biopsy based on the highest FDG uptake. However, KFD can predispose to localized FDG uptake and limit the specificity of PET/CT by mimicking malignancy. Thus, positive results of PET/CT should be interpreted with caution.

Splenic uptake on FDG PET/CT correlates with Kikuchi-Fujimoto disease severity.

Kikuchi-Fujimoto disease (KFD) is usually self-limiting, but prolonged systemic symptoms often result in frequent hospital visits, long admission durations, or missed workdays. We investigated the role of fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing KFD severity. We reviewed the records of 31 adult patients with pathologically confirmed KFD who underwent 18F-FDG PET/CT between November 2007 and April 2018 at a tertiary-care referral hospital. Disease severity was assessed using criteria based on clinical manifestations of advanced KFD. Systemic activated lymph nodes and severity of splenic activation were determined using semi-quantitative and volumetric PET/CT parameters. The median of the mean splenic standardized uptake value (SUVmean) was higher in patients with severe KFD than those with mild KFD (2.38 ± 1.18 vs. 1.79 ± 0.99, p = 0.058). Patients with severe KFD had more systemically activated volume and glycolytic activity than those with mild KFD (total lesion glycolysis: 473.5 ± 504.4 vs. 201.6 ± 363.5, p = 0.024). Multivariate logistic regression showed that myalgia (odds ratio [OR] 0.035; 95% confidence interval [CI] 0.001-0.792; p = 0.035), total lymph node SUVmax (cutoff 9.27; OR 24.734; 95% CI 1.323-462.407; p = 0.032), and spleen SUVmean (cutoff 1.79; OR 37.770; 95% CI 1.769-806.583; p = 0.020) were significantly associated with severe KFD. 18F-FDG PET/CT could be useful in assessing KFD severity.

Kikuchi Cervical Lymphadenitis in Children: Ultrasound Differentiation From Common Infectious Lymphadenitis.

OBJECTIVES: To investigate ultrasound (US) features of enlarged cervical lymph nodes (LNs) to differentiate between Kikuchi disease (KD) and other common types of infectious lymphadenitis in an East Asian pediatric patient population. METHODS: A total of 142 pediatric patients with KD and 45 patients with infectious lymphadenitis (suppurative lymphadenitis [n = 29], nontuberculous mycobacterial lymphadenitis [n = 9], and tuberculous lymphadenitis [n = 7]) were included. The clinical characteristics, laboratory results, and US features of LNs were reviewed. The area under the curve (AUC) from a receiver operating characteristic curve analysis was used as a diagnostic accuracy measure. RESULTS: A multiple clustered adjacent pattern, bilaterality, an even size, posterior neck involvement, no enlargement, an elongated-to-ovoid shape, homogeneous hypoechogenicity, a well-defined margin, presence of an echogenic fatty hilum, no intranodal gross necrosis, increased perinodal fat echogenicity, and no increased echogenicity of the adjacent sternocleidomastoid muscle were significant US features of the affected LNs to discriminate KD from infectious lymphadenitis (P < .05). Homogeneous hypoechogenicity in KD showed the highest AUC (0.930) as a single variable (95% confidence interval, 0.88-0.96). The AUCs were increased in 3 combination models with 2 US features: homogeneous echogenicity and 1 of 3 other US features (increased perinodal fat echogenicity, 0.935; number of affected LNs, 0.947; and LN shape, 0.949). CONCLUSIONS: Homogeneous hypoechogenicity of LNs was a significant US feature with the highest diagnostic accuracy in differentiating KD from common infectious lymphadenitis on a univariate analysis. In the combination model, US features of an elongated-to-ovoid shape and homogeneous hypoechogenicity showed the highest diagnostic accuracy.

PET/Computed Tomography in Pulmonary and Thoracic Inflammatory Diseases (Including Cardiac Sarcoidosis): The Current Role and Future Promises.

18F-fluorodeoxyglucose PET/computed tomography (CT) can play a valuable adjunct role in initial and post-treatment assessment of thoracic and pulmonary inflammatory disorders and is particularly helpful when the conventional biomarkers and anatomical imaging are non-contributory or inconclusive. PET/CT can potentially help in chronic obstructive pulmonary disease (COPD). Quantitative regional parameters of inflammation, perfusion, and ventilation estimated by PET/CT have the potential to cause a paradigm shift in the management of COPD. This article highlights the role of PET/CT in thoracic inflammatory disorders, with an overview of newer aspects such as quantification, disease phenotyping, new tracers, and new techniques.

Cervical lymphadenopathy in children: a diagnostic tree analysis model based on ultrasonographic and clinical findings.

OBJECTIVES: To establish a diagnostic tree analysis (DTA) model based on ultrasonography (US) findings and clinical characteristics for differential diagnosis of common causes of cervical lymphadenopathy in children. METHODS: A total of 242 patients (131 boys, 111 girls; mean age, 11.2 ± 0.3 years; range, 1 month-18 years) with pathologically confirmed Kikuchi disease (n = 127), reactive hyperplasia (n = 64), lymphoma (n = 24), or suppurative lymphadenitis (n = 27) who underwent neck US were included. US images were retrospectively reviewed to assess lymph node (LN) characteristics, and clinical information was collected from patient records. DTA models were created using a classification and regression tree algorithm on the basis of US imaging and clinical findings. The patients were randomly divided into training (70%, 170/242) and validation (30%, 72/242) datasets to assess the diagnostic performance of the DTA models. RESULTS: In the DTA model based on all predictors, perinodal fat hyperechogenicity, LN echogenicity, and short diameter of the largest LN were significant predictors for differential diagnosis of cervical lymphadenopathy (overall accuracy, 85.3% and 83.3% in the training and validation datasets). In the model based on categorical parameters alone, perinodal fat hyperechogenicity, LN echogenicity, and loss of fatty hilum were significant predictors (overall accuracy, 84.7% and 86.1% in the training and validation datasets). CONCLUSIONS: Perinodal fat hyperechogenicity, heterogeneous echotexture, short diameter of the largest LN, and loss of fatty hilum were significant US findings in the DTA for differential diagnosis of cervical lymphadenopathy in children. KEY POINTS: • Diagnostic tree analysis model based on ultrasonography and clinical findings would be helpful in differential diagnosis of pediatric cervical lymphadenopathy. • Significant predictors were perinodal fat hyperechogenicity, heterogeneous echotexture, short diameter of the largest LN, and loss of fatty hilum.

Is recurrent Kikuchi-Fujimoto disease a precursor to systemic lupus erythematosus?

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare, benign, self-limiting disease characterized by cervical lymphadenopathy and fever. Since KFD was first reported in 1972, the validity of this clinical entity has been controversial and its aetiology remains unknown. Herein, we report a case of a patient with KFD, which was believed to be associated with systemic lupus erythematosus.

Case Report: Kikuchi: The great mimicker.

Kikuchi-Fujimoto disease is a form of a benign necrotizing lymphadenitis which is most commonly misdiagnosed as tuberculosis and or lymphoma, usually more common among young adults in Asia. It is a benign disease but can mimic a lot of other disease processes spanning infectious, rheumatologic and even hematologic malignancies. Our patient presented with prolonged fever and lymphadenopathy. Initial considerations were lymphoma and a nonspecific viral infection. A CT scan showed diffuse cervical lymphadenopathy with lacrimal gland involvement. An excisional lymph node biopsy was done which revealed Kikuchi disease. Patient was given steroids with immediate response with defervescence. Kikuchi is a disease with many mimics and a complete workup is needed to exclude serious disease like malignancy.

Three children of meningoencephalitis with Kikuchi necrotizing lymphadenitis.

BACKGROUND: Kikuchi necrotizing lymphadenitis (KNL) is a rare and benign cause of lymphadenopathy, most often cervical. The etiology of KNL remains unknown. Central nervous system (CNS) involvement, such as in meningoencephalitis, is a very rare clinical manifestation of KNL, especially in children. CASE REPORTS: A 12-year-old boy presented with unilateral cervical lymphadenopathy and fever. Histopathological findings led to the diagnosis of KNL. He revisited due to severe headache and vomiting one week later. Cerebrospinal fluid (CSF) analysis demonstrated pleocytosis (lymphocytic 57%), high protein (312 mg/dL) and low CSF/serum glucose ratio (52/121 mg/dL.) The next day, he had a seizure. Brain MRI revealed increased signal involving posterior area of both hemisphere. Another 17-year-old boy presented with headache for 7 days and behavioral and personality changes. He had a history of cervical lymphadenopathy two weeks ago. CSF analysis demonstrated lymphocytosis, high protein and low glucose ratio. MRI revealed the involvement of right cerebellum and posterior brainstem. A biopsy of one cervical lymphadenopathy demonstrated the findings of KNL. A 15-year-old girl presented with fever, headache, and cervical pain lasting 10 days. CSF analysis demonstrated pleocytosis (lymphocytic 95%), high protein and low CSF/serum glucose ratio. Histopathological findings of lymph node were suggestive of KNL. Above three patients were undertaken the steroid therapy and recovered fully without neurological dysfunction. CONCLUSIONS: Recognition of CNS involvement in KNL may help evaluate the patients of acute meningitis/encephalitis with regional lymphadenopathy, thereby avoiding unnecessary treatment.

CT pattern analysis of necrotizing and nonnecrotizing lymph nodes in Kikuchi disease.

OBJECTIVE: The purpose of this study was to determine whether a CT interpretation with imaging pattern analysis differentiates Kikuchi disease (KD) from the two more frequently encountered differential lymph nodes diagnoses of tuberculous lymphadenopathy (TL) and reactive hyperplasia (RH). MATERIALS AND METHODS: Between January 2012 and July 2015, 20 patients with KD (6 men, 14 women; mean age, 27.80 years), 36 patients with RH (10 men, 26 women; mean age, 33.08 years) and 34 patients with TL (17 men, 17 women; mean age, 39.82 years) were pathologically diagnosed using US-guided fine needle aspiration biopsy, core needle biopsy, or surgical excisional biopsy. We recorded the total number, location, and size of the affected cervical lymph nodes, and two radiologists reviewed the characteristic imaging findings, including the presence of necrosis, cortical enhancement pattern, perinodal infiltration, conglomeration and nodal calcification, to form a consensus. In addition, we compared two attenuation indices on the nonnecrotic portion of the affected lymph nodes, nodal cortical attenuation (NCA) and the ratio of NCA to the adjacent muscle (NCA/M). RESULTS: Conglomeration, enhancement pattern and NCA/M values were independent predictive CT features to distinguish KD from RH. Age and enhancement pattern discriminated KD from TL. Only the mean NCA/M value was a statistically significant CT feature (p = .008) in differentiating KD from both RH+TL. The mean NCA/M of KD (1.67 ± 0.20) was significantly higher than that of RH (1.49 ± 0.20) or TL (1.47 ± 0.21). CONCLUSION: Our results indicate that in case of nonnecrotic lymphadenopathy, a higher NCA/M index can differentiate KD from RH and TL. In addition, the enhancement pattern according to the degree of necrosis discriminated between KD and TL in the case of necrotic lymphadenopathy.

Role of Real-Time Elastography in the Evaluation of Cervical Lymph Nodes in Patients with Kikuchi Disease.

The purpose of this study was to compare the use of conventional ultrasound (US) and real-time elastography (RTE) in Kikuchi disease (KD, n = 48) and malignant cervical lymphadenopathy (n = 100) and to evaluate the role of RTE in patients suspected of having KD. In univariate analysis, conventional US revealed each benign feature more frequently in KD than in malignant lymphadenopathy (p < 0.05). However, a considerable number of cases (29, 60.4%) of KD were assessed as malignant with US. KD was assessed as benign by RTE more frequently than malignant lymphadenopathy (37 [77.1%] vs. 37 [37.0%], p < 0.001). In multivariate analysis, perinodal hyper-echogenicity was predictive of KD (odds ratio: 67.25, confidence interval: 10.95-413.04, p < 0.001). There was a tendency for KD to be assessed as malignant with conventional US, but benign with RTE. RTE can help to avoid unnecessary biopsy in patients suspected of having KD on the basis of conventional US.

Comparison of Ultrasonographic Findings of Biopsy-Proven Tuberculous Lymphadenitis and Kikuchi Disease.

OBJECTIVE: Although tuberculous lymphadenitis and Kikuchi disease are common causes of cervical lymphadenopathy in Asians and exhibit similar clinical manifestations, their treatment strategies are totally different. The purpose of this study was to identify ultrasonographic features that distinguish these two diseases. MATERIALS AND METHODS: This study was approved by the Institutional Review Board. The study included 77 patients with tuberculous lymphadenitis and 135 patients with Kikuchi disease. The sex and age distributions of the patients were analyzed. The size and shape of lymph nodes (LNs), presence of conglomeration, increased perinodal echogenicity, echogenic hilum, posterior neck involvement, internal calcification, patterns of internal necrosis, laterality of involved LNs, and hilar vascular patterns on ultrasonography were compared between the two groups. Multiple logistic regression analysis was conducted to identify independent findings to discriminate tuberculous lymphadenitis from Kikuchi disease. Finally, diagnostic accuracies were calculated using the independent findings. RESULTS: The presence of an echogenic hilum, internal calcification, patterns of internal necrosis, and LN hilar vascular structures on power Doppler ultrasonography were independent findings that discriminated tuberculous lymphadenitis from Kikuchi disease. The diagnostic accuracy of each of these four factors was 84.9% (181/212), 76.9% (163/212), 84% (178/212), and 89.2% (189/212), respectively. A combination of internal calcification and hilar vascular structures showed the best accuracy of 89.6% (190/212) (sensitivity, 86.7% [117/135]; specificity, 94.8% [73/77]) for diagnosing Kikuchi disease. CONCLUSION: The presence of an echogenic hilum, internal calcification, pattern of internal necrosis, and LN hilar vascular structures are useful ultrasonographic findings to differentiate tuberculous lymphadenitis from Kikuchi disease.