Kikuchi-Fujimoto disease. Is Epstein-Barr virus the culprit?

Kikuchi-Fujimoto disease: A comprehensive review

Kikuchi-Fujimoto disease, a rare form of necrotizing lymphadenitis, is an uncommon, benign, self-limiting disorder of obscure etiology. It affects mostly young adults of both genders. Clinically, it presents with fever and lymphadenopathy of a firm to rubbery consistency frequently involving cervical lymph nodes while weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients. Cutaneous involvement occurs in about 30%-40% of cases as facial erythema and nonspecific erythematous papules, plaques, acneiform or morbilliform lesions of great histologic heterogeneity. Both Kikuchi-Fujimoto disease and systemic lupus erythematosus share an obscure and complex relationship as systemic lupus erythematosus may occasionally precede, develop subsequently, or sometimes be associated concurrently with Kikuchi-Fujimoto disease. It is often mistaken for non-Hodgkin lymphoma while lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's disease, drug eruptions, infectious mononucleosis, and viral or tubercular lymphadenitis are other common differentials. Fine needle aspiration cytology mostly has features of nonspecific reactive lymphadenitis and immunohistochemistry studies usually show variable features of uncertain diagnostic value. Since its diagnosis is exclusively from histopathology, it needs to be evaluated more carefully; an early lymph node biopsy will obviate the need for unnecessary investigations and therapeutic trials. Its treatment with systemic corticosteroids, hydroxychloroquine, or antimicrobial agents mostly remains empirical. The article reviews clinicoepidemiological, diagnostic, and management aspects of KFD from the perspective of practicing clinicians.

Immunopathology of Kikuchi-Fujimoto disease: A reappraisal using novel immunohistochemistry markers

AIMS

Kikuchi-Fujimoto disease (KFD) is a self-limited disease characterised by destruction of the lymph node parenchyma. Few studies have assessed the immunohistological features of KFD, and most employed limited antibody panels that lacked many of the novel immunohistochemistry markers currently available.

METHODS AND RESULTS

We used immunohistochemistry to reappraise the microanatomical distribution of plasmacytoid dendritic cells (pDCs), follicular helper T cells and cytotoxic T cells, B cells, follicular dendritic cell (FDC) meshworks, and histiocytes in lymph nodes involved by KFD. The study group consisted of 138 KFD patients (89 women; 64.5%) with a median age of 27 years (range, 3-50 years). Cervical lymph nodes were most commonly involved, in 108 (78.3%) patients. The numbers of pDCs were increased, predominantly around and within apoptotic areas and the paracortex, and tapering off within xanthomatous areas. pDCs formed sizeable tight clusters, most notably around apoptotic/necrotic areas. T cells consisted mostly of CD8-positive cells with predominant expression of T-cell receptor-β. There were notable increases in the numbers of CD8-positive T cells within lymphoid follicles, and their numbers correlated with alterations in FDC meshworks (P < 0.001). The number of follicular helper T cells was decreased within distorted FDC meshworks. CD21 highlighted frequent distortion of FDC meshworks, even in lymph node tissue that was distant from apoptotic/necrotic areas. Distorted FDC meshworks spanned all morphological patterns, and FDC meshwork characteristics (intact; distorted; remnant/nearly absent) correlated with morphological patterns (P < 0.01).

CONCLUSIONS

The immunohistological landscape of KFD is complex and characterised by increased numbers of pDCs that frequently cluster around apoptotic/necrotic foci, increased numbers of cytotoxic T cells, and substantial distortion of FDC meshworks.

Strong association of Torque teno virus/Torque teno-like minivirus to Kikuchi-Fujimoto lymphadenitis (histiocytic necrotizing lymphadenitis) on quantitative analysis

INTRODUCTION

Kikuchi-Fujimoto disease (KFD) is a rare benign lymphadenitis that mainly involves cervical lymph nodes of young Asian women with unknown etiology. Recently, we experienced a case of KFD found with Torque teno virus/Torque teno-like mini virus (TTV/TTMV) from a 26-year-old woman. TTV/TTMV is a genus of Circoviridae that causes necrotizing lymphadenitis in pigs, which shares the key histologic finding of KFD. The purpose of this study is to investigate the pathogenic role of TTV/TTMV in KFD by quantitative polymerase chain reaction (qPCR) analysis.

METHOD

We performed two-step qPCR specific to TTV/TTMV with formalin-fixed paraffin-embedded tissue of sequentially selected 100 KFD patients and 50 randomly selected, matched normal controls. Consequent direct sequencing was done for confirmation with PCR products.

RESULTS

PCR amplification of TTV and TTMV was found in a significantly higher proportion in KFDs than normal controls (TTV, 85% vs. 18%, p < 0.000; TTMV, 91% vs. 24%, p < 0.000). After the sequencing, KFD samples showed more sequence matching than control samples for TTMV (94% vs. 30%, p < 0.000).

CONCLUSION

This finding strongly suggests the possible implication of TTV/TTMV in the pathogenesis of KFD. Animal or in vivo experimental design should be followed in the future.Key Points• Kikuchi-Fujimoto disease (KFD) is rare and its etiology is still unclear.• Torque teno/Torque teno-like minivirus (TTV/TTMV) is a recently introduced virus in the Circoviridae family that causes necrotizing lymphadenitis in pigs, histologically similar to KFD.• We discovered the significantly increased TTV/TTMV viral loads in the KFD patients than normal controls, which implicates TTV/TTMV in the pathogenesis of KFD.

Simultaneous Acquired Self-limited Hemophagocytic Lymphohistiocytosis and Kikuchi Necrotizing Lymphadenitis in a 16-Year-Old Teenage Girl: A Case Report and Review of the Literature

OBJECTIVES

The aim of this study was to increase education and awareness among pediatric practitioners of possibility of simultaneous hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease/Kikuchi disease occurring in the pediatric population and the diagnostic dilemma it can present. We describe a case presentation of acquired and self-limited simultaneous hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease in a 16-year-old in the United States who presented with fevers, night sweats, and joint pain, along with tiredness and decreased appetite along with pancytopenia and elevated lactate dehydrogenase. To the best of our knowledge, simultaneous hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto in the pediatric population has not been described in North America but remains fairly common in Asia. The literature on both diseases and their simultaneous occurrence is comprehensively reviewed.

METHODS

This was a case report and review of the literature.

RESULTS

The patient was diagnosed with both hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease based on bone marrow aspiration/biopsy and axillary node biopsy, respectively. Both illnesses resolved completely.

CONCLUSIONS

Benign causes of pancytopenia and elevated lactate dehydrogenase exist, but they may not be always straightforward diagnostically. Bone marrow aspiration and lymph node biopsy may be helpful in ascertaining the diagnosis. Hemophagocytic lymphohistiocytosis and Kikuchi-Fujimoto disease may represent a continuum of illness.

Kikuchi-Fujimoto disease: retrospective study of 91 cases and review of the literature

Kikuchi-Fujimoto disease (KFD) is a rare cause of lymphadenopathy, most often cervical. It has been mainly described in Asia. There are few data available on this disease in Europe. We conducted this retrospective, observational, multicenter study to describe KFD in France and to determine the characteristics of severe forms of the disease and forms associated with systemic lupus erythematosus (SLE). We included 91 cases of KFD, diagnosed between January 1989 and January 2011 in 13 French hospital centers (median age, 30 ± 10.4 yr; 77% female). The ethnic origins of the patients were European (33%), Afro-Caribbean (32%), North African (15.4%), and Asian (13%). Eighteen patients had a history of systemic disease, including 11 with SLE. Lymph node involvement was cervical (90%), often in the context of polyadenopathy (52%), and it was associated with hepatomegaly and splenomegaly in 14.8% of cases. Deeper sites of involvement were noted in 18% of cases. Constitutional signs consisted mainly of fever (67%), asthenia (74.4%), and weight loss (51.2%). Other manifestations included skin rash (32.9%), arthromyalgia (34.1%), 2 cases of aseptic meningitis, and 3 cases of hemophagocytic lymphohistiocytosis. Biological signs included lymphocytopenia (63.8%) and increase of acute phase reactants (56.4%). Antinuclear antibodies (ANAs) and anti-DNA antibodies were present in 45.2% and 18% of the patients sampled, respectively. Concomitant viral infection was detected in 8 patients (8.8%). Systemic corticosteroids were prescribed in 32% of cases, hydroxychloroquine in 17.6%, and intravenous immunoglobulin in 3 patients. The disease course was always favorable. Recurrence was observed in 21% of cases. In the 33 patients with ANA at diagnosis, SLE was known in 11 patients, diagnosed concomitantly in 10 cases and in the year following diagnosis in 2 cases; 6 patients did not have SLE, and 4 patients were lost to follow-up (median follow-up, 19 mo; range, 3-39 mo). The presence of weight loss, arthralgia, skin lesions, and ANA was associated with the development of SLE (p < 0.05). Male sex and lymphopenia were associated with severe forms of KFD (p < 0.05). KFD can occur in all populations, irrespective of ethnic origin. Deep forms are common. An association with SLE should be investigated. A prospective study is required to determine the risk factors for the development of SLE.

Causative agents of Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis): a meta-analysis

OBJECTIVE

Kikuchi-Fujimoto disease (KFD) is a self-limiting disorder characterized by histiocytic necrotizing lymphadenitis in the cervical lymph nodes of young women. Although an infectious etiology has been postulated, a definitive causative agent has not been identified. The few dozens of published studies are limited by small sample size and poorly structured study designs. The purpose of this study is to evaluate the association of each infectious agent to KFD that has been studied.

METHODS

We performed metaanalysis using major electronic database (MEDLINE (PubMed), Cochrane library, Embase, Web of Science, NML gateway, LILACS, and Google Scholar). Cross-sectional studies on the positivity of each agent in clinicopathologically diagnosed KFD and normal controls by polymerase chain reaction (PCR) or in situ hybridization (ISH) were carefully retrieved. The included infectious agents were herpes simplex virus (HSV) type 1, 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus (EBV), human herpes virus (HHV) 6, 7, 8, parvovirus B19, human papilloma virus, hepatitis B virus, human T-lymphotropic virus 1, Brucella, and Bartonella henselae.

RESULTS

After an exclusion process of 2491 studies, five, two, four, two, two, and three studies on EBV-PCR, EBV-ISH, HHV6-PCR, HHV8-PCR, parvovirus B19-PCR and HHV7-PCR, respectively, were suitable for quantitative meta-analysis.

CONCLUSION

The most suspected pathogen, EBV was not associated to KFD than normal controls (odds ratio=0.28, p=0.005), while the HHV8 positivity was more likely to be associated (odds ratio=8.24, p=0.003) although it still needs further verification. None of other viruses was associated to KFD although the results are limited by small sample size. More studies with large sample size and strict sample selection criteria are necessary in future.

Kikuchi-Fujimoto disease: retrospective study of 91 cases and review of the literature

Kikuchi-Fujimoto disease (KFD) is a rare cause of lymphadenopathy, most often cervical. It has been mainly described in Asia. There are few data available on this disease in Europe. We conducted this retrospective, observational, multicenter study to describe KFD in France and to determine the characteristics of severe forms of the disease and forms associated with systemic lupus erythematosus (SLE). We included 91 cases of KFD, diagnosed between January 1989 and January 2011 in 13 French hospital centers (median age, 30 ± 10.4 yr; 77% female). The ethnic origins of the patients were European (33%), Afro-Caribbean (32%), North African (15.4%), and Asian (13%). Eighteen patients had a history of systemic disease, including 11 with SLE. Lymph node involvement was cervical (90%), often in the context of polyadenopathy (52%), and it was associated with hepatomegaly and splenomegaly in 14.8% of cases. Deeper sites of involvement were noted in 18% of cases. Constitutional signs consisted mainly of fever (67%), asthenia (74.4%), and weight loss (51.2%). Other manifestations included skin rash (32.9%), arthromyalgia (34.1%), 2 cases of aseptic meningitis, and 3 cases of hemophagocytic lymphohistiocytosis. Biological signs included lymphocytopenia (63.8%) and increase of acute phase reactants (56.4%). Antinuclear antibodies (ANAs) and anti-DNA antibodies were present in 45.2% and 18% of the patients sampled, respectively. Concomitant viral infection was detected in 8 patients (8.8%). Systemic corticosteroids were prescribed in 32% of cases, hydroxychloroquine in 17.6%, and intravenous immunoglobulin in 3 patients. The disease course was always favorable. Recurrence was observed in 21% of cases. In the 33 patients with ANA at diagnosis, SLE was known in 11 patients, diagnosed concomitantly in 10 cases and in the year following diagnosis in 2 cases; 6 patients did not have SLE, and 4 patients were lost to follow-up (median follow-up, 19 mo; range, 3-39 mo). The presence of weight loss, arthralgia, skin lesions, and ANA was associated with the development of SLE (p < 0.05). Male sex and lymphopenia were associated with severe forms of KFD (p < 0.05). KFD can occur in all populations, irrespective of ethnic origin. Deep forms are common. An association with SLE should be investigated. A prospective study is required to determine the risk factors for the development of SLE.

Kikuchi-Fujimoto Disease Associated with Symptomatic CD4 Lymphocytopenia

Kikuchi-Fujimoto disease is a rare benign condition of necrotising histiocytic lymphadenitis with unknown aetiology. We describe here a 30-year-old African American female who presented with fever, generalized rash, cervical lymphadenopathy, and oral candidiasis and was found to have Kikuchi-Fujimoto disease on lymph node biopsy with low CD4 count. The initial presentation was concerning for acute retroviral infection. Her HIV serology and HIV RNA PCR were negative however she had low CD4 count with reversal of CD4/CD8 ratio. Although low CD4 count has been associated with autoimmune disease, it has not been described with Kikuchi-Fujimoto disease. We report the first case of Kikuchi-Fujimoto disease associated with symptomatic CD4 lymphocytopenia.

Kikuchi-fujimoto disease in the United States: three case reports and review of the literature [corrected]

Kikuchi-Fujimoto Disease (KFD), also known as histiocytic necrotizing lymphadenitis [corrected], is a benign, self-limiting disease that manifests primarily as cervical lymphadenopathy but may include low-grade fever, headache, and fatigue. There is a higher incidence of KFD in women aged 20-35 years and in Asian populations. A PubMed search revealed 590 articles that described KFD. Of these, 22 cases have been fully described in the United States. Ten of the 22 (45%) patients were male and 12 (55%) were female, with 20% Caucasian, 20% Asian American, and the remaining 60% of other ethnic backgrounds. In this study, we describe an additional 3 cases of KFD and discuss the diagnosis, pathology, and management of KFD.

Features of Sequential CT and US-guided Biopsy in Recurrent Kikuchi Disease of the Neck: A Case Report

A 26-year-old woman presented with recurrent Kikuchi disease 7 years after her initial episode. Computed tomography (CT) and ultrasonography demonstrated enlarged lymph nodes with extensive necrosis at the same site as the initial episode. Cytologic and histologic examinations were not conclusive. CT performed 1 month later demonstrated a complete resolution of the lymphadenopathy, which confirmed the diagnosis of recurrent Kikuchi disease. Care must be taken to avoid misdiagnosis of recurrent Kikuchi disease as tuberculous lymphadenitis.

Kikuchi's disease

Kikuchi disease is an idiopathic, generally self-limiting cause for lymphadenitis that can be clinically and histologically mistaken for lymphoma or systemic lupus erythematosus. Differentiating this disease from common lymphatic disorder is extremely important from the pathologist's point of view, which is highlighted in the article.

Cervical Lymphadenopathy Secondary to Kikuchi-Fujimoto Disease in a Child: Case Report

While most cases of cervical lymphadenopathy resolve with conservative management, persistent adenopathy can lead to costly investigations and invasive treatments. One cause of persistent adenopathy, as well as a variety of other associated systemic symptoms, is Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis). This rare entity can he diagnosed only by excisional biopsy on the basis of its characteristic histologic appearance. We describe a case of persistent cervical lymphadenopathy secondary to Kikuchi-Fujimoto disease in an 11-year-old girl.

Disseminated Kikuchi-Fujimoto disease: a case report

Subacute necrotizing lymphadenitis or Kikuchi-Fujimoto disease is a benign pathological entity diagnosed chiefly in young adults. We report a case in a 20-year-old woman who presented with swollen lymph nodes and a fever. Disseminated lymphadenopathy with nodes measuring up to 6 cm in diameter was found upon physical examination. The erythrocyte sedimentation rate was elevated to 40 mm/h and the lactic dehydrogenase level to 593 IU/l. Findings were negative from serological tests for rubella, hepatitis B, hepatitis C, HIV, and toxoplasmosis, as well as from tests for tuberculosis. A biopsy of a cervical lymph node showed nonsuppurative necrosis, karyorrhexis, and a marked histiocytic reaction consistent with Kikuchi-Fujimoto disease. No treatment was given, and a full recovery was achieved within 3 months. In this patient, the disseminated lymphadenopathy and constitutional symptoms strongly suggested a hematological malignancy and more specifically a lymphoproliferative disease.

Adverse antibiotic-induced eruptions associated with epstein barr virus infection and showing Kikuchi-Fujimoto disease-like histology

The antibiotic-induced eruption of infectious mononucleosis is a well-known clinical phenomenon. Latent viral infection with herpesviridae (eg, human herpes virus 6 (HHV-6) and Epstein-Barr virus (EBV)) is suspected to play a role in the drug hypersensitivity syndrome. The cutaneous pathologic findings have not been reported in the former, and are infrequently reported in the latter entity. Herein, we describe the biopsy findings of a cefprozil-induced rash in infectious mononucleosis and a minocycline-associated drug hypersensitivity syndrome. Biopsy of these exanthematous eruptions revealed an acute vacuolar interface superficial and deep perivascular and interstitial lymphocytic dermatitis. CD8(+) lymphocytes predominated and were associated with non-neutrophilic nuclear (karyorrhectic) debris and numerous small CD68(+) and CD123(+) monocytes. These aforementioned features have been described in cutaneous lesions of Kikuchi-Fujimoto disease, an entity whose clinicopathologic findings overlap with both infectious mononucleosis and lupus erythematosus. Serologic evidence of active and chronic active EBV infection was found in both patients, respectively. No evidence of EBV or HHV6 was found in the cutaneous lesions. Plasmacytoid monocytes (CD68(+)/CD123(+) cells), which produce type I interferon, are believed to play a role in viral immunity by protecting other cells from viral infections and promoting survival of antigen-activated T cells. Their presence in these two putative examples of viral-drug immune dysregulation could be a clue to pathogenesis and represent a common cellular component of some adverse cutaneous drug eruptions.

Kikuchi Fujimoto disease secondary to Entamoeba histolytica: case report

Kikuchi Fujimoto disease (KFD) is a rare histiocytic necrotizing lymphadenitis which has a benign self-limiting clinical course. Its origin is unknown, but an abnormal autoimmune reaction has been suggested and infection is often considered to be an inciting agent. A 50-year-old man presented with fever, malaise, fatigue and sweat of 7 days duration, and diarrhea for 2 days. Physical examination revealed five mobile and painless cervical adenopathies. Entamoeba histolytica trophozoites and cysts were detected by microscopy of feces. Parenteral ornidazole treatment was commenced. Thorax computerized tomography showed lymph node sizes congruent with infection in the mediastinum, right hilus and right axillary region. Axillary lymph node biopsy and immunohistochemical analyses were then performed, and the results were consistent with histiocytic necrotizing lymphadenitis. From day 4 of antibiotic treatment the patient's body temperature decreased and reached a normal level on day 10. After discharge the patient returned for follow-up twice and was asymptomatic; his lymph nodes were either unpalpable or were decreased in size. We could not find any previous study or case report about a probable role for E. histolytica. Amebiasis can be a triggering factor in KFD or alternatively it is possible that its occurrence is coincidental.

Oligoclonal T cells in histiocytic necrotizing lymphadenopathy are associated with TLR9+ plasmacytoid dendritic cells

Histiocytic necrotizing lymphadenopathy (HNL), a disease of unknown cause, is characterized pathologically by the presence of plasmacytoid dendritic cells (pDCs), which are frequently mixed with oligoclonal T cells (OTCs) and myeloid cells. Toll-like receptors (TLRs 1-10) are a family of pattern recognition receptors of DCs. To investigate the interactions between pDCs and T cells, and to look for an etiology of HNL, we studied 24 HNLs for the profile of TLRs. Transcripts of TLR7, a receptor on pDCs for single-stranded RNA, were found in every case, confirming the universal presence of pDCs. Transcripts of TLR9, another receptor on pDCs for microbial unmethylated CpG-rich DNA, were correlated with OTCs, implying T-cell expansion stimulated by TLR9+ pDCs in response to a microbe. Because PCRs for bacterial 16S rDNAs were negative in the lymph nodes, a bacterial origin seems unlikely, but a virus remains a possible candidate. The pDCs lacked the maturation marker CD83, which suggested ineffective stimulation of T cells and might account for the usually benign course of HNL. Taken together, these data illustrate a novel approach, based upon TLR transcript analysis, for the integration of pathology, immunology, and clinical findings of HNL.

Giardia lamblia intestinalis: a new pathogen with possible link to Kikuchi-Fujimoto disease. An additional element in the disease jigsaw

A 16-year-old Caucasian girl of Albanian origin was admitted to the hospital complaining of intermittent fever (38 degrees C) for a week, nausea, vomiting, and abnormal laboratory findings (elevated serum aminotransferases levels AST/ALT 77/40 U/l and erythrocyte sedimentation rate 80 mm/first hour, as well as leukopenia 2.5 x 10(3)/mm3), which were found in a blood examination. Physical examination revealed slight hepatomegaly and splenomegaly, as well as cervical and axillary lymphadenopathy. A diagnostic open lymph node biopsy was performed and Kikuchi-Fujimoto disease (KFD) was established based on the characteristic histological pattern. Other abnormal laboratory findings were C-reactive protein 6.8 mg/dl and serum lactate dehydrogenase 900 U/l. Her history included a diarrhoea syndrome 2 months before the present admission, during the summer holidays, for which she was treated with metronidazole. At that time, characteristic cysts of giardia lamblia intestinalis were observed in the stools. Herein, we present this case hypothesising that the protozoal infection caused by the giardia lamblia intestinalis was probably triggering an immune response leading to KFD. The patient's age in combination with this firstly reported protozoal pathogen, as a triggering agent leading to KFD, consist a very interesting originality. Additionally, some review data is also given.

Kikuchi-Fujimoto disease: a rare but important cause of lymphadenopathy

Cervical lymphadenopathy is a common problem in children. Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis) is a rare condition that causes persistent lymphadenopathy and has a characteristic histological appearance. Kikuchi-Fujimoto disease is well recognized in Japan, where it was first described, but descriptions in the paediatric literature are sparse. Paediatricians may therefore be unaware of this rare but important condition. The case is described of a 14-y-old girl suffering from fatigue, weight loss, night sweats and lymphadenopathy. The predominance of systemic symptoms prompted an extensive investigation. The diagnosis of Kikuchi-Fujimoto disease was made after direct histological examination of a lymph node biopsy. The case illustrates the clinical features of this little-known condition and highlights the potential confusion with other diagnoses. The pathological features are discussed and the literature reviewed.

CONCLUSION

Kikuchi-Fujimoto disease should be considered in cases of persistent lymphadenopathy. An early biopsy can be instrumental in preventing unnecessary investigations and potentially harmful treatments.

Kikuchi-Fujimoto lymphadenitis

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, was initially described as a distinct histologic pattern of lymphadenitis generally associated with a benign self-limited clinical course. While most common in Southeast Asia, where KFD was initially described in 1972 in young women, this lesion has since been reported in patients of virtually any age, gender, or ethnic background from a variety of geographic locations, including the United States. In addition, cases showing extranodal involvement have been described. The spectrum of clinical and histologic features associated with this disorder suggest that KFD more likely represents a common pattern of response to a variety of etiologic factors rather than a single clinicopathologic entity. In this review, the characteristic clinical, laboratory, histologic, and immunophenotypic features of this disorder are described, with emphasis on differential diagnosis with other types of necrotizing lymphadenitis and with malignant lymphoma. Unusual clinical presentations and features of disease when present at extranodal sites are also reviewed.

Lack of human herpesvirus 8 and Epstein-Barr virus in Kikuchi's histiocytic necrotizing lymphadenitis

Kikuchi's histiocytic necrotizing lymphadenitis is a self-limited disorder that typically involves the cervical lymph nodes of young women. Although a viral etiology has been postulated, a definitive viral agent has not been identified. Recent reports have suggested that human herpesvirus 8 (HHV 8) or Epstein-Barr virus (EBV) may play an etiologic role. We investigated the presence of HHV 8 and EBV in archival tissue from 34 cases of Kikuchi's histiocytic necrotizing lymphadenitis. We examined 29 cases for HHV 8 using a nested polymerase chain reaction (PCR) on paraffin-embedded or frozen tissue, and 24 cases for EBV RNA using in situ hybridization (ISH) for EBER1. Controls included reactive lymph nodes from 8 adult women presenting with cervical or axillary lymphadenopathy. The study patients included 7 men and 27 women with a mean age of 28 years. All patients were previously healthy without evidence of immunocompromise and presented with cervical, axillary, or inguinal lymphadenopathy. Two cases exhibited EBV RNA by ISH; this was confirmed by PCR for EBV DNA. HHV 8 DNA was not amplified by nested PCR in any of the cases of Kikuchi's histiocytic necrotizing lymphadenitis or reactive lymph nodes; control PCR demonstrated the presence of amplifiable DNA in all cases. These findings suggest that HHV 8 and EBV do not play causative roles in Kikuchi's histiocytic necrotizing lymphadenitis.

Kikuchi disease presenting as a flu-like illness with rash and lymphadenopathy

Kikuchi-Fujimoto disease (Kikuchi Disease) is a self-limited and benign systemic lymphadenitis of unknown cause, originally described by Kikuchi and Fujimoto and coworkers in 1972. Although relatively uncommon, it is increasingly discussed in the medical literature. Clinical presentation typically includes adenopathy, particularly cervical, with fever and flu-like symptoms. This constellation of symptoms, in the presence of a characteristic histiocytic necrotizing lymphadenitis, provides the clinicopathologic diagnosis. The immunopathogenesis of Kikuchi disease may lie in a hyperactive response to viral infection. We describe an African American man with Kikuchi disease, unusual in the extent of his rash and debilitation, and in the relapse of his clinical symptoms.