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.

Expression of Programmed Cell Death 1 Ligands (PD-L1 and PD-L2) in Histiocytic and Dendritic Cell Disorders.

Programmed cell death 1 ligands 1 and 2 (PD-L1 and PD-L2) are cell surface proteins expressed by activated antigen-presenting cells and by select malignancies that bind PD-1 on T cells to inhibit immune responses. Antibodies targeting PD-1 or PD-L1 elicit antitumor immunity in a subset of patients, and clinical response correlates with PD-1 ligand expression by malignant or immune cells within the tumor microenvironment. We examined the expression of PD-1 ligands on subsets of antigen-presenting cells and 87 histiocytic and dendritic cell disorders including those that are benign, borderline, and malignant. Within reactive lymphoid tissue, strong PD-L1 is detected on most macrophages, subsets of interdigitating dendritic cells, and plasmacytoid dendritic cells, but not on follicular dendritic cells or Langerhans cells. Macrophage/dendritic cell subsets do not express discernible PD-L2. Seven of 7 cases of sarcoidosis (100%), 6 of 6 cases of histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease) (100%), 2 of 11 cases of Rosai-Dorfman disease (18%), and 3 of 15 cases of Langerhans cell histiocytosis (20%) exhibited positivity for PD-L1. All cases of sarcoidosis were also positive for PD-L2. Seven of 14 histiocytic sarcomas (50%), 2 of 5 interdigitating dendritic cell sarcomas (40%), 10 of 20 follicular dendritic cell sarcomas (50%), and none of 9 blastic plasmacytoid dendritic cell neoplasms were positive for PD-L1. Eleven of 20 (55%) follicular dendritic cell sarcomas were also positive for PD-L2. PD-L1 and PD-L2 are useful new markers for identifying select histiocyte and dendritic cell disorders and reveal novel patient populations as rational candidates for immunotherapy.

Plasmacytoid Dendritic Cells Producing Interferon-α (IFN-α) and Inducing Mx1 Play an Important Role for CD4(+) Cells and CD8(+) Cells in Necrotizing Lymphadenitis.

We confirmed the characteristic clinical features of necrotizing lymphadenitis (NEL) in 66 cases (23 male, 43 female) in Japan, which included high fever (38-40°), painful cervical lymphadenopathy (62/66, 93.9%), and leukopenia (under 4,000/mm(3)) (25/53, 47.2%), without seasonal occurrence, in a clinicopathological, immunohistochemical, electron microscopic serological study. Patient age varied from 3-55 years, and 72.7% (44/66) of patients were younger than 30 years. Histopathology of NEL was characterized by the presence of CD8(+) immunoblasts, CD123(+) cells (plasmacytoid dendritic cells; PDCs), histiocytes and macrophages phagocytizing CD4(+) apoptotic lymphocytes, but no granulocytes or bacteria. The number of PDCs and CD8(+) cells in lesions tended to increase with time, and PDCs tended to be larger and irregular in the lesions compared with the non-lesion tissue of the lymph nodes. In addition, PDCs showed no temporal morphological change in the lymph nodes. The number of CD4(+) cells in the lymph node lesions sharply decreased from the 2nd to the 4th week, and then tended to increase; however, CD4(+) cells gradually decreased with time in non-lesion tissue. PDCs may produce interferon-α (IFN-α), which induces Mx1 expression. Strong Mx1 immunoreactivity is indicative of IFN-α production. IFN-α induces transformation of CD8(+) cells into immunoblasts, as well as phagocytosis of apoptotic cells derived from CD4(+) cells by macrophages. Thus, PDCs may play an important role with immune cells, including CD8(+) and CD4(+) cells, in necrotizing lymphadenitis.

[Significance of CD123 in histiocytic necrotizing lymphadenitis].

OBJECTIVE: To investigate the mode of presentation, cytologic features of the plasmacytoid dendritic cells (pDC), and the expression of CD123 and its significance in Kikuchi's disease. METHODS: CD123 expression was evaluated by EliVision immunohistochemical staining in formalin-fixed and paraffin-embedded tissues from 30 cases of Kikuchi's disease, 5 cases of T cell lymphoma, 10 cases of reactive lymphoid hyperplasia and 10 cases of chronic tonsillitis. RESULTS: Clusters of CD123 positive PDC were observed in Kikuchi's disease (28 of 30 cases, 93.3%) and the staining intensity was more prominent in the PDC at the periphery of the lesion and around the high endothelial venule-like vessels. CD123 showed three staining patterns: membranous (10 cases, 33.3%), cytoplasmic (10 cases, 33.3%), and membranous and cytoplasmic (8 cases, 26.7%). In the control group, CD123 showed cytoplasmic staining in reactive hyperplasia and chronic tonsillitis. Regarding the staining intensity, 12 of 28 cases (42.9%) were 3+ for CD123, 8 of 28 cases (28.6%) were 2+, and 8 of 28 cases (28.6%) were 1+. In contrast, PDC clusters with 1+ staining intensity were observed in 1 of 10 cases of reactive lymphoid hyperplasia; 2 of 10 chronic tonsillitis diseases; and much less in T cell lymphoma. CONCLUSIONS: Large cluster of PDC is detected in both proliferative and necrotizing types of Kikuchi's disease, making this a useful adjunctive diagnostic marker.

Sweet's syndrome complicated by Kikuchi's disease and hemophagocytic syndrome which presented with retinoic acid-inducible gene-I in both the skin epidermal basal layer and the cervical lymph nodes.

A 21-year-old man was admitted to our hospital with a fever, erythema, cervical lymphadenopathy and pancytopenia. A diagnosis of Sweet's syndrome (SS) with Kikuchi's disease (KD) and hemophagocytic syndrome (HPS) was made based on the results of a bone marrow aspiration along with the results from biopsy specimens of the brachial skin and a cervical lymph node. The expression of retinoic acid-inducible gene-I (RIG-I) in the skin epidermal basal layer as well as in a cervical lymph node was revealed through immunohistochemistry. He successfully entered remission through treatment with prednisolone. This findings of this case indicate that when SS with KD presents as HPS, it may suggest an association with an RIG-I-related innate immunity.

Splenic manifestations of chronic autoimmune disorder: a report of five cases with histiocytic necrotizing change in four cases.

AIMS: Autoimmune diseases (AD) are associated with lymphadenopathy and splenomegaly. Changes in the spleen have not been characterized completely in AD; we describe splenectomy specimens from five patients with chronic AD, highlighting the presence of necrotizing histiocytosis. METHODS AND RESULTS: Of the patients (three males and two females; mean 40 years), four had systemic lupus erythematosus; one had rheumatoid arthritis. All had moderate splenomegaly (213-803 g, mean 421 g). Four cases exhibited necrosis with apoptosis and karyorrhectic debris occurring in the white pulp and minimal acute inflammation; one showed florid follicular hyperplasia. Splenic involvement ranged from focal to extensive. Plasma cells were negative for IgG4. Haematoxylin bodies were not identified. Stains for infectious organisms were negative. Immunohistochemical studies showed that lymphocytes surrounding the necrosis were a mixture of CD4(+) and CD8(+) T cells; CD123-positive plasmacytoid dendritic cells were not present, and staining for kappa and lambda light chains showed no clonality. 16S rDNA PCR was performed; no amplification was seen in three of four cases tested for bacteria specific rDNA. Epstein-Barr virus-encoded RNA (EBER) in situ hybridization studies highlighted rare positive cells in four cases. CONCLUSIONS: Splenomegaly in AD is thought to be hyperplasic, but we present four cases showing histiocytic necrosis, a finding which should be considered part of the spectrum of AD in the spleen.

A non-invasive diagnosis of histiocytic necrotizing lymphadenitis by means of gene expression profile analysis of peripheral blood mononuclear cells.

Histiocytic necrotizing lymphadenitis (HNL), also called Kikuchi-Fujimoto disease, is a benign, self-limiting inflammatory disease with fever and painful cervical lymphadenopathy of unknown etiology. A lymph node biopsy is required for the definitive diagnosis because of no specific symptoms or laboratory findings for HNL. To establish the rapid non-invasive diagnostic method for this disease, we investigated genes specifically expressed in the patients by analyzing whole transcriptome using microarray analysis of peripheral blood mononuclear cells (PBMC). The top five up-regulated genes (IFI44L, CXCL10, GBP1, EPSTI1 and IFI27) in HNL were interferon-induced genes (ISGs). The expression levels of the up-regulated genes by microarray were verified by quantitative PCR. High levels of serum CXCL10 concentration were confirmed at the symptomatic phase of HNL patients. The expression levels of these 5 genes positively correlated with each other (r(2) = 0.28-0.60). The genes were also highly expressed in HNL lymph nodes. The discriminant analysis using the expression levels of these five genes distinguished HNL with 84% accuracy. The combination of up-regulated ISGs in HNL seemed to be a specific response induced by viral infections or autoantigens. An analysis of the gene expression profile of PBMC may provide a rapid non-invasive diagnosis of HNL.

Clinicopathological review of immunohistochemically defined Kikuchi-Fujimoto disease-including some interesting cases.

Kikuchi-Fujimoto Disease (KFD) is a benign, self-limited disease characterized by tender regional lymphadenopathy with fever. KFD remains a poorly defined disease, and no clear diagnostic criteria are available. Here, we assess the clinical, laboratory, and histopathologic findings of KFD cases and report two unusual cases. Forty KFD patients that underwent lymph node (LN) biopsy and diagnosed by immunohistochemical staining, from January 2003 to November 2010, were enrolled in this retrospective study. The patients had a mean age of 29.3 years, and 29 (72.5 %) were women. Affected LNs were mainly located unilaterally in the cervical area. Mean LN size was 15.3 mm. Twenty-eight (70 %) patients had LN tenderness, and 25 (62.5 %) patients had fever. Leukopenia was observed in 18 of 35 evaluable patients. C-reactive protein and erythrocyte sedimentation rate were elevated in most patients. Anti-nuclear antibody was positive in four of 19 evaluable patients, but all had been diagnosed with concurrent systemic lupus erythematosus. Histologically, the 40 cases were classified into three types, that is, as proliferative (37.5 %), necrotizing (55.0 %), or xanthomatous (7.5 %). Interesting cases: Case 1 was a 35-year-old female with KFD and uveitis, retinal vasculitis, and superior sagittal sinus thrombosis. Case 2 was a 47-year-old male with KFD and bone marrow involvement and presented with severe bicytopenia. Although KFD is an uncommon self-limited benign disorder, it must be included in the differential diagnosis of lymphadenopathy with fever and cytopenia. It is important that the clinical features of KFD be understood to reach a correct diagnosis.

The cutaneous lesions of Kikuchi's disease: a comprehensive analysis of 16 cases based on the clinicopathologic, immunohistochemical, and immunofluorescence studies with an emphasis on the differential diagnosis.

Kikuchi's disease is a self-limited necrotizing lymphadenitis that is characterized by cervical lymphadenopathy and fever. Although it has been reported that some patients with Kikuchi's disease have cutaneous manifestations, the specific skin changes of patients with Kikuchi's disease have not been fully described. We report here on 16 patients of Kikuchi's disease with cutaneous manifestations. We reviewed the clinical histories of the patients who underwent lymph node and skin biopsies. Immunohistochemistry, immunofluorescence, and Epstein-Barr virus-encoded RNA (EBER) in situ hybridization were performed. The patients ranged in age from 7 to 39 years and included 4 males and 12 females. All the patients had histiocytic necrotizing lymphadenitis. The clinical impression was variable according to the various cutaneous manifestations. The skin biopsies showed vacuolar interface changes (12/16; 75.0%), necrotic keratinocytes (11/16; 68.8%), superficial (16/16; 100.0%) and deep (9/16; 56.3%) lymphohistiocytic infiltration, karyorrhexis (16/16; 100.0%), deposition of mucin (5/16; 31.3%), and panniculitis (9/15; 60.0%). Based on immunohistochemistry, the infiltrating cells were predominantly CD68 and CD163-positive histiocytes and CD3-positive T lymphocytes. Of the 16 patients, 13 (81.3%) had a slight predominance of CD8-positive lymphocytes. Direct immunofluorescence staining and EBER in situ hybridization were all negative. Although the clinical and histopathologic findings are very heterogenous, the presence of a lymphohistiocytic infiltration with nonneutrophilic karyorrhexis helps to make the diagnosis of Kikuchi's disease with skin involvement.

Phenotype for activated tissue macrophages in histiocytic necrotizing lymphadenitis.

Macrophage polarization is divided into M1 and M2 type based on membrane receptors, cytokines, and chemokines. M1 expresses CD80, interleukin (IL)-6, IL-12, and chemokine receptor (CCR)7, while M2 expresses CD163, IL10, and chemokine ligand (CCL)22. The aim of the present study was to identify the properties of infiltrating tissue macrophages in histiocytic necrotizing lymphadenitis (HNL). Twenty patients with HNL were studied, and immunohistochemistry for CD68 (KP1), CD163, CCL22, CCR7, and CD123 was done, along with myeloperoxidase (MPO). To evaluate the phenotypes of tissue macrophages in HNL, the number of cells stained positively for CD163, CCL22, CCR7, CD123 and MPO concurrently with CD68 was counted, and the ratio was calculated for each antibody to CD68+ cells. There was a high rate of co-expression for CD163 (median, 78%) or CCL22 (80%) and a low rate for CCR7 (5%) in CD68+ cells. It is therefore conceivable that infiltration by M2 macrophages is dominant in HNL. Furthermore, some CD68+ tissue macrophages in HNL co-express MPO or CD123 (range, 5-80%; median, 23% and 40%, respectively). It is suggested that these characteristic tissue macrophages may be associated with the pathogenesis of HNL and that M2 macrophages may infiltrate to repair the lymphoid tissue injured by cytotoxic T cells in HNL.

Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease): lesional cells exhibit an immature dendritic cell phenotype.

Histiocytic necrotizing lymphadenitis (HNL) is a rare benign disorder characterized histologically by nodal lesions composed of histiocytes, lymphoid cells, and so-called plasmacytoid T cells/plasmacytoid monocytes, with associated karyorrhexis. It has been proposed that plasmacytoid monocytes represent immature myeloid and lymphoid (plasmacytoid) early-committed dendritic cells (DCs). Monoclonal antibodies are now available for the detection of myeloid (CD1c [BDCA-1]+) and plasmacytoid (CD303 [BDCA-2]+) dendritic cells. With an extensive panel of antibodies to immature and mature DCs and interferon-alpha (IFN-alpha), cryostat section studies of 6 cases of HNL revealed that the morphologically distinctive mononuclear cells in lesional areas consisted of 2 populations of immature DCs: myeloid DCs immunoreactive for CD1c with coexpression of myeloid antigens CD13 and CD33 and plasmacytoid DCs immunoreactive for CD303 and CD123. These cells were CD68+, strongly expressed the IFN-alpha inducible protein MxA, and were nonreactive for fascin, a mature DC marker.

Histiocytic necrotizing lymphadenitis without granulocytic infiltration (the so called Kikuchi-Fujimoto disease).

The report describes five cases of a rare disorder--necrotizing lymphadenitis--diagnosed in Polish patients in the Department of Pathomorphology, Collegium Medicum, Jagiellonian University, Krakow, in the years 1993-2006. The disease was firstly described by Kikuchi and Fujimoto in the Oriental population of Japan in 1972 and for this reason it is called Kikuchi-Fujimoto disease (or Kikuchi lymphadenitis). Its characteristic histological picture includes necrosis without granulocytic infiltrate surrounded by plasmocytoid monocytes, histiocytes (CD68+, lysozyme+, myeloperoxidase+) and immunoblasts, sometimes with atypia, with concomitant lymphocytes, predominantly cytotoxic T CD8+. The histology together with the rare occurrence of the disease in Poland may be a considerable diagnostic challenge for a pathologist, leading to misdiagnosing the lesion as a neoplastic process (malignant lymphoma).

Estimation of apoptosis and cell proliferation in histiocytic necrotizing lymphadenitis using immunohistochemical double staining.

The aim of the present study was to estimate the relationship between apoptosis and cell proliferation in histiocytic necrotizing lymphadenitis (HNL). Fifteen patients with HNL were retrospectively analyzed. The patients were divided into three groups according to the proportion of the necrotic area as follows: necrosis (+), necrotic area <25%; necrosis (++), necrotic area 25-50%; and necrosis (+++), necrotic area >50%. Immunohistochemical double staining was performed for CD3 plus caspase-3 and for Ki-67 plus caspase-3 and positive cells were counted in two areas: one without and one with obvious apoptotic features. Most caspase-3-positive cells were also stained for CD3 (area exhibiting obvious apoptotic features: average, 92.3%). Furthermore, various proportions of both Ki-67- and caspase-3-positive cells were detected in all the groups (range, 5-70%). In the area with obvious apoptotic changes, the average percentage of both Ki-67- and caspase-3-positive cells (38.6%) was higher than that in the area without obvious apoptotic features (16.3%). A proportion of cells in HNL undergo proliferation and apoptosis simultaneously, such as neoplastic cells, thereby exhibiting rapid cell cycles.

Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease (KFD) is a benign and self-limited disorder, characterized by regional cervical lymphadenopathy with tenderness, usually accompanied with mild fever and night sweats. Less frequent symptoms include weight loss, nausea, vomiting, sore throat. Kikuchi-Fujimoto disease is an extremely rare disease known to have a worldwide distribution with higher prevalence among Japanese and other Asiatic individuals. The clinical, histopathological and immunohistochemical features appear to point to a viral etiology, a hypothesis that still has not been proven. KFD is generally diagnosed on the basis of an excisional biopsy of affected lymph nodes. Its recognition is crucial especially because this disease can be mistaken for systemic lupus erythematosus, malignant lymphoma or even, though rarely, for adenocarcinoma. Clinicians' and pathologists' awareness of this disorder may help prevent misdiagnosis and inappropriate treatment. The diagnosis of KFD merits active consideration in any nodal biopsy showing fragmentation, necrosis and karyorrhexis, especially in young individuals presenting with posterior cervical lymphadenopathy. Treatment is symptomatic (analgesics-antipyretics, non-steroidal anti-inflammatory drugs and, rarely, corticosteroids). Spontaneous recovery occurs in 1 to 4 months. Patients with Kikuchi-Fujimoto disease should be followed-up for several years to survey the possibility of the development of systemic lupus erythematosus.

Different T-bet expression patterns characterize particular reactive lymphoid tissue lesions.

AIMS: To investigate T-bet expression profiles in various lymphoid tissue diseases caused by intracellular pathogens and to compare them in disorders without an infective aetiology. Murine and in vitro experiments have shown that the expression/induction of T-bet, the master regulator of Th1 differentiation, can be achieved by obligate intracellular pathogens and high interferon (IFN)-gamma levels. METHODS: Lymph node biopsies were analysed immunohistochemically employing single and double labelling for T-bet and CD20, CD4, CD8 and CD30 detection. RESULTS: In disorders associated with high IFN-gamma levels and intracellular pathogens (infectious mononucleosis, HIV-associated lymphadenopathy, cat-scratch disease, and toxoplasmic lymphadenitis), T-bet-expressing CD4 cells were accompanied by significant numbers of T-bet-positive CD8 and B cells. A similar profile was also found in histiocytic necrotizing (Kikuchi) lymphadenitis, a disease of unknown cause. In contrast, T-bet expression in disorders without an infective aetiology was observed in only a small portion of lymphocytes. CONCLUSIONS: Increased T-bet expression does not only identify intracellular infections in lymphoid tissue associated with high IFN-gamma levels, but also implies that, under these conditions, it becomes induced in B cells, which apparently support the Th1 response. T-bet expression in Kikuchi lymphadenitis underscores the hypothesis that it is caused by an intracellular microorganism.

Histiocytic necrotising lymphadenitis (Kikuchi-Fujimoto disease) in Saudi Arabia: clinicopathology and immunohistochemistry.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a rare entity of uncertain cause that commonly presents as a benign self-limiting disease of unknown origin. The objective of this study was to document the clinical features, mode of presentation, histopathological and immunohisto-chemical (IHC) features of KFD at our institutions since little is known about this disease in our region. METHODS: We reviewed the histopathological reports of all lymph nodes resected at or referred to King Abdulaziz University Hospital between 1990 and 2003 and King Faisal Specialist Hospital & Research Center, Jeddah, Kingdom of Saudi Arabia between 2000 and 2003. All cases diagnosed as KFD were identified and the histological slides and clinical data were reviewed. IHC was performed for the proliferative marker Ki-67 and the apoptosis-related markers Bcl-2 and p53. RESULTS: In 2500 lymph node biopsies, 15 cases were diagnosed as KFD. The female to male ratio was 2.7:1. One patient presented with axillary lymphadenopathy and the others presented with cervical lymphadenopathy. Ages averaged 29 years and ranged from 13 to 46 years. There was no recurrence of the lymphadenopathy over 1 to 10 years of follow up. Bcl-2 and p53 were negative and Ki-67 was positive in 11 of 15 cases. CONCLUSION: The results support earlier findings that KFD is a self-limiting disorder that requires no specific management. We suggest a clinical follow-up for several years. The female predominance was striking. Apoptosis-regulating proteins are not helpful in the diagnosis. KFD usually expressed the proliferation-associated nuclear antigen Ki-67. Increased awareness of KFD will minimize the risk of confusing this entity with malignant lymphoma or other serious conditions.