Distinguishing lupus lymphadenitis from Kikuchi disease based on clinicopathological features and C4d immunohistochemistry

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.

Systemic lupus in the era of machine learning medicine

Artificial intelligence and machine learning applications are emerging as transformative technologies in medicine. With greater access to a diverse range of big datasets, researchers are turning to these powerful techniques for data analysis. Machine learning can reveal patterns and interactions between variables in large and complex datasets more accurately and efficiently than traditional statistical methods. Machine learning approaches open new possibilities for studying SLE, a multifactorial, highly heterogeneous and complex disease. Here, we discuss how machine learning methods are rapidly being integrated into the field of SLE research. Recent reports have focused on building prediction models and/or identifying novel biomarkers using both supervised and unsupervised techniques for understanding disease pathogenesis, early diagnosis and prognosis of disease. In this review, we will provide an overview of machine learning techniques to discuss current gaps, challenges and opportunities for SLE studies. External validation of most prediction models is still needed before clinical adoption. Utilisation of deep learning models, access to alternative sources of health data and increased awareness of the ethics, governance and regulations surrounding the use of artificial intelligence in medicine will help propel this exciting field forward.

Clonal T-cell proliferations occasionally occur in Kikuchi-Fujimoto disease

Kikuchi-Fujimoto disease (KFD) is a benign self-limiting disorder that frequently leads to swelling of cervical lymph nodes in young women. It has a characteristic histologic appearance with sharply demarcated foci containing apoptotic debris, histiocytes, and proliferating large T-cells. Since in the past years, core needle biopsies have been increasingly used for diagnostic work-up, a small biopsy of the pathognomonic proliferating T-cell foci may lead to misinterpretation as a large T-cell neoplasia. The aim of the present study therefore was to analyze how frequently clonal T-cell receptor (TCR) amplificates may be obtained in KFD using a commonly used TCR gamma rearrangement clonality assay. In 88 KFD cases, TCR gamma clonality assays could be successfully applied. Clonal peaks of TCR gamma in front of a polyclonal background were observed in 15 cases (18%). The investigated clinical parameters (age, gender, extent of infiltration of the lymph node, percentage of proliferative compartment) did not differ between patients with detectable TCR gamma clones from those patients who had polyclonal TCR gamma results. Our study therefore demonstrates that clonal TCR gamma amplificates may be obtained in any type of KFD and that an over-interpretation of clonal T-cell proliferates in diagnostically equivocal material should be avoided.

Understanding the role and adoption of artificial intelligence techniques in rheumatology research: An in-depth review of the literature

The major and upward trend in the number of published research related to rheumatic and musculoskeletal diseases, in which artificial intelligence plays a key role, has exhibited the interest of rheumatology researchers in using these techniques to answer their research questions. In this review, we analyse the original research articles that combine both worlds in a five- year period (2017-2021). In contrast to other published papers on the same topic, we first studied the review and recommendation articles that were published during that period, including up to October 2022, as well as the publication trends. Secondly, we review the published research articles and classify them into one of the following categories: disease identification and prediction, disease classification, patient stratification and disease subtype identification, disease progression and activity, treatment response, and predictors of outcomes. Thirdly, we provide a table with illustrative studies in which artificial intelligence techniques have played a central role in more than twenty rheumatic and musculoskeletal diseases. Finally, the findings of the research articles, in terms of disease and/or data science techniques employed, are highlighted in a discussion. Therefore, the present review aims to characterise how researchers are applying data science techniques in the rheumatology medical field. The most immediate conclusions that can be drawn from this work are: multiple and novel data science techniques have been used in a wide range of rheumatic and musculoskeletal diseases including rare diseases; the sample size and the data type used are heterogeneous, and new technical approaches are expected to arrive in the short-middle term.

Necrosis in lymph nodes and their differential diagnoses: application of reticulin staining

This study aimed to enhance the histopathological diagnosis of necrotic lymph node specimens. A chart review was conducted, revealing that the most common causes of lymph node necrosis were Kikuchi disease (33%), granulomatous inflammation (25%), metastasis (17%), and lymphomas (12%). Histological analysis of necrotic tissue in 333 specimens demonstrated significant differences between the four diseases. The necrotic tissue of Kikuchi disease was amorphous, and hypercellular, and exhibited karyorrhexis and congestion. Granulomatous inflammation presented amorphous necrotic tissue with a nodular-like pattern. Metastasis exhibited heterogeneous morphology that varied between cancer types. Lymphomas displayed extensive necrosis with ghost cells, congestion, and bubbles. Reticulin staining patterns also differed between diseases. Kikuchi disease and lymphomas exhibited preserved reticular fiber networks in the necrotic tissue, resembling the viable tissue. Granulomatous inflammation and metastasis showed disrupted reticular fiber networks in the necrotic tissue. Based on these findings, histological features and reticulin staining patterns can aid in diagnosing Kikuchi disease, granulomatous inflammation, metastasis, and lymphomas in necrotic lymph node specimens.

Diagnostic Dilemma in a Case of Necrotizing Lymphadenitis With Macrophage Activation Syndrome

Necrotizing lymphadenitis is a histological diagnosis that can arise from various conditions, including lupus lymphadenitis (LL), Kikuchi disease (KD), and infectious causes. Distinguishing between Kikuchi disease and lupus lymphadenitis can be challenging in clinical practice. In this report, we present the clinical scenario of a young female patient with lymphadenopathy and elucidate the process through which we ultimately arrived at a diagnosis of systemic lupus erythematosus (SLE) with macrophage activation syndrome. This case underscores the significance of recognizing Kikuchi disease as a condition that can mimic lupus and sheds light on the distinguishing features of necrotizing lymphadenitis, with a particular focus on Kikuchi disease and lupus lymphadenitis.

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.

Systemic Lupus Erythematosus Lymphadenopathy Presenting as Kikuchi-Fujimoto Disease in an Adolescent

Systemic lupus erythematosus is a multisystem autoimmune disorder with a highly heterogeneous clinical presentation. The clinical phenotype varies from mild cutaneous and musculoskeletal manifestations to neurological involvement. Lymphadenopathy is a frequent manifestation of SLE, but the association is often not recognized, as lymphadenopathy is not a criterion for diagnosis. An unusual and seldom reported mimicker of lupus lymphadenitis is Kikuchi-Fujimoto Disease. This is a rare self-limiting disease of young adult females that presents with lymphadenopathy, fever, and systemic symptoms. Lupus lymphadenitis and KFD share some common clinical and pathologic features; but distinguishing between those two diseases can be challenging. We describe a 16-year-old Hispanic female who presented with axillary lymphadenopathy and was initially diagnosed with KFD based on an excisional lymph node biopsy; but later met the criteria for the 2019 European League Against Rheumatism/American College of Rheumatology classification criteria SLE. This case highlights the need for clinicians to be aware that patients with SLE may present with lymphadenopathy and to consider the association between Kikuchi disease and SLE to prevent misdiagnosis and allow for timely treatment to avoid complications.

Small Tweaks, Major Changes: Post-Translational Modifications That Occur within M2 Macrophages in the Tumor Microenvironment

The majority of proteins are subjected to post-translational modifications (PTMs), regardless of whether they occur in or after biosynthesis of the protein. Capable of altering the physical and chemical properties and functions of proteins, PTMs are thus crucial. By fostering the proliferation, migration, and invasion of cancer cells with which they communicate in the tumor microenvironment (TME), M2 macrophages have emerged as key cellular players in the TME. Furthermore, growing evidence illustrates that PTMs can occur in M2 macrophages as well, possibly participating in molding the multifaceted characteristics and physiological behaviors in the TME. Hence, there is a need to review the PTMs that have been reported to occur within M2 macrophages. Although there are several reviews available regarding the roles of M2 macrophages, the majority of these reviews overlooked PTMs occurring within M2 macrophages. Considering this, in this review, we provide a review focusing on the advancement of PTMs that have been reported to take place within M2 macrophages, mainly in the TME, to better understand the performance of M2 macrophages in the tumor microenvironment. Incidentally, we also briefly cover the advances in developing inhibitors that target PTMs and the application of artificial intelligence (AI) in the prediction and analysis of PTMs at the end of the review.

Morphologic Spectrum of Lymphadenopathy in Drug Reaction With Eosinophilia and Systemic Symptoms Syndrome

CONTEXT.—

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DRESS) is a drug-induced, adverse T-cell-mediated hypersensitivity reaction that most often involves skin. The pathologic findings of DRESS-related lymphadenopathy have been described infrequently in the literature.

OBJECTIVE.—

To present a case series of DRESS-related lymphadenopathy with an emphasis on the morphologic spectrum.

DESIGN.—

We describe detailed clinical and pathologic findings along with the literature review. We focus on the differential diagnosis between DRESS lymphadenopathy and angioimmunoblastic T-cell lymphoma (AITL).

RESULTS.—

There were 4 men and 1 woman with a mean age of 41 years (range, 23-59 years). One patient (20%) died. Three lymph node biopsy specimens showed a pattern reminiscent of AITL (AITL-like pattern) and 2 cases showed necrotizing lymphadenitis (Kikuchi-like pattern), associated with vasculitis in 1 case. The AITL-like morphology of DRESS-related lymphadenopathy may be difficult to distinguish from genuine AITL. The clinical information is important for differential diagnosis, including history of drug exposure, age, and the rarity or absence of AITL-associated manifestations such as hemolytic anemia and hypergammaglobulinemia. Molecular analysis of the T-cell receptor genes is helpful, typically revealing a polyclonal pattern in DRESS-related lymphadenopathy.

CONCLUSIONS.—

In the literature, 4 histologic patterns of DRESS lymphadenopathy have been described: reactive lymphoid hyperplasia, necrotizing lymphadenitis, Hodgkin lymphoma-like, and AITL-like. These patterns, particularly those that resemble lymphoma, highlight the importance of correct diagnosis to avoid unnecessary therapies.

Adult-onset Still's disease with multiple lymphadenopathy: a case report and literature review

BACKGROUND

Adult-onset Still's disease (AOSD) often presents with systemic multiple lymphadenopathy. In addition to the common paracortical and mixed patterns in AOSD lymph node histopathological features, other morphological patterns include diffuse, necrotic, and follicular patterns. However, to date, there have been few reports on the histopathological description of AOSD lymph nodes.

CASE PRESENTATION

An 18-year-old woman presented 2 months earlier with pain in her large joints with painless rash formation; bilateral posterior cervical lymph node, left supraclavicular lymph node, and left posterior axillary lymph node enlargement, and no tenderness. Left cervical lymph node resection was performed for pathological examination. The lymph node structure was basically preserved, and subcapsular and medullary sinus structures were observed. Many histiocytes in the sinus were observed, the cortical area was reduced, a few lymphoid follicles of different sizes were observed, and some atrophy and hyperplasia were noted. The lymphoid tissue in the paracortical region of the lymph node was diffusely proliferative and enlarged, mainly comprising histiocytes with abundant cytoplasm, immunoblasts and numerous lymphocytes with slightly irregular, small- to medium-sized nuclei. Nuclear karyorrhexis was easily observed, showing a few nuclear debris and the "starry sky" phenomenon, accompanied by abundantly branching high endothelial small vessels with few scattered plasma cells and eosinophil infiltration. Lymphoid follicle immunophenotype with reactive proliferative changes was observed. Approximately 40% of the cells in the paracortical region were positive for Ki-67, and the histiocytes expressed CD68, CD163, and some expressed S-100, with the absence of myeloperoxidase. The immunoblasts expressed CD30 and CD20, not ALK or CD15. Background small- to medium-sized T cells expressed CD2, CD3, CD5, CD7, CD4, and CD8; the number of CD8-positive T cells was slightly predominant, and a small number of T cells expressed granzyme B and T-cell intracellular antigen 1. The patient received a comprehensive medical treatment after the operation, and her condition was stable without progression at the 11-month follow-up evaluation.

CONCLUSIONS

The pathological features of AOSD lymphadenopathy raises the awareness of AOSD among pathologists and clinicians and aids in the diagnosis and differential diagnosis of AOSD lymphadenopathy from other reactive lymphadenopathies (lupus lymphadenitis, etc.) and lymphomas.