Histiocytic necrotizing lymphadenitis in children: a clinical and immunohistochemical comparative study with adult patients

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.

Pathogenesis, diagnosis, and management of Kikuchi-Fujimoto disease

BACKGROUND

Kikuchi-Fujimoto disease (KFD) is a rare lymphohistiocytic disorder with an unknown etiopathogenesis. This disease is misdiagnosed as malignant lymphoma in up to one-third of cases and is associated with the development of systemic lupus erythematosus (SLE).

METHODS

The medical literature between the years 1972 and 2014 was searched for KFD, and the data were collected and analyzed regarding the epidemiology, clinical presentations, diagnosis, management, and suggested diagnostic and treatment algorithms.

RESULTS

Although KFD has been reported in other ethnic groups and geographical areas, it is more frequently diagnosed in young women of Asian descent. Patients with the disease typically present with rapidly evolving tender cervical lymphadenopathy, night sweats, fevers, and headache. Diagnosis is based on histopathological examination. Excisional lymph node biopsy is essential for a correct diagnosis. Apoptotic coagulation necrosis with karyorrhectic debris and the proliferation of histiocytes, plasmacytoid dendritic cells, and CD8(+) T cells in the absence of neutrophils are characteristic cytomorphology features. Interface dermatitis at the onset of KFD may be a marker for the subsequent evolution of SLE. The natural course of the disease is typically benign. Short courses of steroids, nonsteroidal anti-inflammatory drugs, or hydroxychloroquine can be administered to patients with more severe symptoms.

CONCLUSIONS

Although KFD was described more than 40 years ago, the etiology of this disease remains unsolved. Infectious or autoimmune processes were proposed but have not been definitively confirmed. Clinical presentation with systemic B symptoms and adenopathy may lead to an erroneous diagnosis of malignant lymphoma. The introduction of modern methods into hematopathology, including immunohistochemistry, flow cytometry, and molecular clonality studies, has decreased the probability of misdiagnosis. Until reliable prognostic markers are available, patients with KFD should have continued long-term follow-up care due to their increased risk of SLE.

Association between Kikuchi-Fujimoto disease and Streptococcus pneumoniae infection

Kikuchi-Fujimoto disease is a rare histiocytic necrotizing lymphadenitis that affects typically young women causing fever and painful laterocervical lymphadenopathy. The etiology is unknown, but several viral infections and autoimmune diseases have been related with the disease. Bacterial infections are less frequent. Diagnosis needs for excisional lymph node biopsy that shows paracortical areas of coagulative necrosis with abundant debris, distortion of the nodal architecture, and a large amount of histiocytes at the margins of the necrotic areas. There is no specific treatment for the disease. We present the case of a young woman with Kikuchi-Fujimoto disease associated with lower respiratory tract infection by Streptococcus pneumoniae and review the literature.

Recurrent lymphadenopathy in children with Kikuchi-Fujimoto disease

Kikuchi-Fujimoto disease (KFD) is characterized by self-limiting regional lymphadenopathy with prolonged fever. Although the reported recurrence rate of KFD is known to be 3-4 %, this rate appears to be higher in our clinical experience, and rates up to 38.5 % have been previously reported. In this retrospective study, we reviewed medical records of children with pathologically confirmed KFD to investigate the factors associated with recurrent KFD. Enrolled children were divided into two groups according to the recurrence of KFD, and clinical and laboratory factors were compared between the two groups. The recurrence of KFD was determined based not on repeated pathologic confirmation but on the presence of clinical febrile lymphadenopathy. A total of 33 children with KFD, 26 boys (78.8 %) and 7 girls (21.2 %), with a median age of 12 years (9 months to 19 years), were enrolled. Thirty-one children (93.9 %) complained of fever, and most of the children (90.9 %) complained of cervical lymphadenopathy. Neutropenia (<1,500/μL) or lymphopenia (<1,500/μL) was observed in 51.5 %. Lactate dehydrogenase level, erythrocyte sedimentation rate, and C-reactive protein level were elevated in 90.9, 96.9, and 54.5 % of children, respectively. Fourteen children (42.4 %) experienced recurrent KFD, including ten children after biopsy and four children before and after biopsy. In a multivariate analysis, a past history of other systemic illnesses (p = 0.013) and a higher absolute lymphocyte count (p = 0.023) were significantly associated with recurrent KFD. These systemic illnesses were chronic idiopathic thrombocytopenic purpura, autoimmune thyroiditis, nephrotic syndrome, perinatal cytomegalovirus infection, and hemophagocytic lymphohistiocytosis.

CONCLUSION

Our results suggest that recurrent KFD is more frequent than reported, and recurrent KFD should be considered in children with a history of other systemic illnesses such as immune disorders.

Comparison of clinical features and EBV expression in histiocytic necrotizing lymphadenitis of children and adults

OBJECTIVE

Histiocytic necrotizing lymphadenitis (HNL) is a self-limiting disease characterized by cervical lymphadenopathy and fever. Epstein-Barr virus (EBV) has been implicated as a cause of HNL in some reports but not in others. The aim of this study was to compare the clinical features and laboratory findings in children and adults with HNL and to evaluate the relationship between EBV infection and HNL.

METHODS

The records of patients diagnosed with biopsy-confirmed HNL at Gyeongsang National University Hospital from May 2009 to December 2012 were retrospectively reviewed. Clinical features, laboratory data (blood count, biochemistry, and serology), and computed tomography findings were collected. Immunohistochemistry for CD4, CD8, CD68, and myeloperoxidase (MPO), and in situ hybridization for EBV RNA were performed on archived lymph node biopsies from pediatric and adult patients.

RESULTS

A total of 16 children and 31 adults were diagnosed with HNL. Fever was present in 87.5% of children and 25.8% of adults (P<0.0001). Fever duration was longer for children (mean, 5.06 days) than for adults (mean, 0.63 days; P=0.008). Necrosis of the involved lymph nodes was observed in eight (50%) children and six (19.4%) adults (P=0.045). HNL recurred in five (31.35%) children and one (3.2%) adult (P=0.015). All had detectable CD4, CD8, CD68, and MPO immunoreactivity. EBV reactivity was higher in children (26.7%) than in adults (6.7%) without statistical support.

CONCLUSIONS

There is more variability in the clinical presentation and laboratory findings in children with HNL than in adults. In particular, the degree and duration of fever was more severe in children than in adults, and necrosis of lymph nodes was more frequent in children than in adults. There was no definitive correlation between EBV reactivity and NHL. Further study of the relationship between EBV and HNL is needed with a larger number of patients.

Characteristics of Kikuchi-Fujimoto disease in children compared with adults

Kikuchi-Fujimoto disease (KFD) is a benign, self-limiting disease characterized by cervical lymphadenopathy. Although it was primarily thought to be a disease of young adults, it has been increasingly recognized in children. To define the characteristics of KFD in children, we reviewed the medical records of patients younger than 18 years of age who were diagnosed with KFD from 2001 to 2012 at Korea University Medical Center, as well as worldwide published reports of KFD. A total of 140 pediatric patients and 733 patients of all ages was analyzed. Compared to the female predominance found in adults (2:1), young boys were more commonly affected than young girls (1.4:1). Cervical lymphadenopathy was the most common clinical finding in children, as it was in adults. Lymphadenopathy was more likely to be tender (69 vs. 44 %, p < 0.001) but less generalized (1 vs. 8 %, p < 0.05) in children compared to adults. Fever (82 vs. 35 %, p < 0.001) and rash (10 vs. 4 %, p < 0.05) were observed in children more commonly than in adults. Leukopenia was observed in 50 and 38 % of children and adults, respectively. Rates of recurrence and association with autoimmune diseases in children were comparable to those of adults. Cervical lymphadenopathy was the most common clinical manifestation of KFD in all ages. While fever and rash were more common in children with KFD compared to adults, generalized lymphadenopathy was rarer.