A diagnostic challenge-First case of chronic lymphatic leukemia-associated necrotizing sweet syndrome.

Sweet syndrome, also known as acute febrile neutrophilic dermatosis, is a rare disorder typically characterized by the clinical triad including a sudden onset of fever, painful skin lesions, and neutrophilia. The histopathological findings are a dense neutrophilic infiltrate and oedema of the dermis and epidermis without evidence of a vasculitis. Besides treatment of the underlying cause, sweet syndrome is typically treated with high-dose corticosteroids leading to a relapse-free response in 70% of patients. However, if left unrecognized or untreated, the condition may lead to serious complications. Here, we report on the case of a 38-year-old patient in whom, under the assumption of the presence of necrotizing fasciitis, exarticulation of the right arm was performed. In the absence of pathogen detection and insufficient response to anti-infective therapies, the diagnosis of a sweet syndrome was assumed and, later, confirmed by an excellent response to high-dose administration of systematic glucocorticoids. The case emphasizes the need to be aware of this rare syndrome, which can be easily misdiagnosed due to its close resemblance to infection and stresses the need of further research to define distinct diagnostic tools.

Persistent Sweet syndrome post-hematopoietic stem cell transplantation heralding molecular relapse of myelofibrosis.

Persistent Sweet syndrome in a patient with history of myelofibrosis thought to be in remission post-hematopoietic stem cell transplantation leads to diagnosis of molecular relapse of myelofibrosis.

Disseminated Yersinia enterocolitica infection associated to Sweet's syndrome.

We report the case of a young woman sough care for disseminated form of Yersinia enterocolitica infection (pseudoappendicitis with mesenteric lymph node, arthralgia, glomerulonephritis and hepatitis) diagnosed on Western Blot method for the detection of Yersinia antibodies. The patient also presented a rare concomitant cutaneous manifestation, as Sweet's syndrome, confirmed histologically. Neutrophilic dermatosis is an exceptional skin features among post-infectious autoimmune disorders when encountering Yersinia enterocolitica infection in clinical practice.

Myelodysplasia cutis and VEXAS syndrome initially diagnosed as histiocytoid Sweet syndrome: A diagnostic pitfall.

Histiocytoid Sweet syndrome (H-SS) is a histopathological variant of Sweet syndrome (SS) defined by cutaneous infiltration of immature myeloid cells morphologically resembling histiocytes. The association of H-SS with underlying malignancy, particularly myelodysplastic syndromes, is well-established. Myelodysplasia cutis (MDS-cutis) has been proposed to describe cases historically diagnosed as H-SS but characterized by shared clonality of the myeloid infiltrate in skin and bone marrow. Therefore, identifying patients who might have MDS-cutis is critical for the management of the associated hematologic malignancy. VEXAS syndrome, an adult-onset autoinflammatory disease, should also be included in the histopathologic differential diagnosis of H-SS, as it shares clinical and pathologic features with MDS-cutis. Through the presentation of two cases, we aim to highlight the defining features and key clinical implications of MDS-cutis and VEXAS syndrome.

Drug-Induced and Malignancy-Associated Neutrophilic Dermatoses in Patients with Hematologic Malignancies: A Single Institution Experience.

INTRODUCTION: Neutrophilic dermatoses (NDs) often occur secondary to inflammatory conditions, medication exposure, and hematologic malignancy. While malignancy-associated NDs (MA-NDs) have been well reported among those with hematologic cancers, little is known about drug-induced NDs (DI-NDs) within this population. The objective of this study was to compare the presentations and outcomes of patients with hematologic malignancies who developed MA-NDs and DI-NDs. METHODS: Cases of ND occurring between 2013 and 2023 among those with hematologic malignancies were identified from the electronic medical records of our institution. Patient characteristics, recent medication exposures, cancer mutations, and disease outcomes were reviewed. Patients were categorized with DI-ND if they were recently exposed to one of four medications known to be commonly associated with ND or were otherwise categorized with MA-ND. We report a descriptive analysis of cases of DI-ND and MA-ND. RESULTS: We identified 52 patients with ND and co-occurring hematologic malignancy including 16 cases of DI-ND (30.8%) and 36 cases of MA-ND (69.2%). The most common ND in both groups was Sweet's syndrome. Chronic underlying conditions including solid tumors, inflammatory disorders, chronic viral infection, and tobacco use were more common among those with MA-ND. Among those with DI-ND, tyrosine kinase inhibitors were the most commonly associated drugs (43.8%). The most common cancer mutation among those with DI-ND was FLT3 (43.8%), while the most common mutation among those with MA-ND was TP-53 (19.4%). Among those who had died at the time of data collection, 90.0% of those with DI-ND and 66.7% of those with MA-ND died within 1 year of ND diagnosis. CONCLUSION: Most cases of ND occurring with hematologic malignancies develop secondary to cancer rather than drug exposure. Different cancer mutations may predispose to DI-ND and MA-ND. Further research is needed to establish diagnostic criteria for DI-ND and to determine the pathogenic role of specific cancer mutations, particularly FLT3, in the development of ND.

Clinical and histological features of histiocytoid Sweet syndrome associated with VEXAS syndrome.

BACKGROUND: VEXAS (Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is caused by acquired somatic mutations in UBA1. Sweet-syndrome-like skin disorders [and especially histiocytoid Sweet syndrome (HSS)] may be associated with VEXAS syndrome. OBJECTIVES: To characterize the clinical and histopathological features of HSS in patients with VEXAS syndrome. METHODS: Skin biopsies with a histological diagnosis of HSS at Rennes University Medical Center (Rennes, France) between October 2011 and January 2022 were reviewed in this study. Sanger sequencing and digital polymerase chain reaction were used to screen skin, blood and bone marrow samples for UBA1 variants, and thus classify patients as having VEXAS syndrome or not. We evaluated the clinical, histological and molecular (UBA1) characteristics of patients with or without VEXAS syndrome. RESULTS: We compared 15 skin biopsies from 7 patients found to have VEXAS syndrome and 19 skin biopsies from 15 patients without VEXAS syndrome. Persistent C-reactive protein elevation, macrocytosis, anaemia and haematological malignancies were more prevalent in patients with VEXAS syndrome [6/7 (86%), 6/7 (86%), 7/7 (100%) and 6/7 (86%), respectively] than in patients without [5/14 (36%), 6/15 (40%), 8/15 (53%) and 8/15 (53%), respectively]. These features sometimes appeared after the first skin manifestations, and a UBA1 mutation was found in the skin of five patients with VEXAS syndrome. Dermal infiltration by reniform histiocytoid cells (myeloperoxidase-positive and/or CD163-positive) and a periadnexal distribution were more frequently observed in VEXAS syndrome biopsies [15/15 (100%) and 3/15 (20%), respectively, vs. 11/19 (58%) and 0/19 (0%) in non-VEXAS syndrome biopsies, respectively]. CONCLUSIONS: Our findings might help pathologists to consider a diagnosis of VEXAS syndrome and to initiate early genetic testing.

Clinical characteristics, disease trajectories and management of vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome: a systematic review.

BACKGROUND: VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a newly discovered autoinflammatory condition characterised by somatic mutation of the UBA1 gene. The syndrome leads to multi-system inflammation affecting predominantly the skin, lungs and bone marrow. METHODS: We undertook a systematic review of the multisystem features and genotypes observed in VEXAS syndrome. Articles discussing VEXAS syndrome were included. Medline, Embase and Cochrane databases were searched. Information was extracted on: demographics, type and prevalence of clinical manifestations, genetic mutations and treatment. Meta-analysis using a random effects model was used to determine pooled estimates of serum markers. RESULTS: From 303 articles, 90 were included, comprising 394 patients with VEXAS. 99.2% were male, with a mean age of 67.1 years (SD 8.5) at disease onset. The most frequent diagnoses made prior to VEXAS were: relapsing polychondritis (n = 59); Sweet's syndrome (n = 24); polyarteritis nodosa (n = 11); and myelodysplastic syndrome (n = 10). Fever was reported in 270 cases (68.5%) and weight loss in 79 (20.1%). Most patients had haematological (n = 342; 86.8%), dermatological (n = 321; 81.5%), pulmonary (n = 297; 75.4%%) and musculoskeletal (n = 172; 43.7%) involvement, although other organ manifestations of varying prevalence were also recorded. The most commonly reported mutations were "c.122T > C pMET41Thr" (n = 124), "c.121A > G pMET41Val" (n = 62) and "c.121A > C pMet41Leu" (n = 52). Most patients received glucocorticoids (n = 240; 60.9%) followed by methotrexate (n = 82; 20.8%) and IL-6 inhibitors (n = 61, 15.4%). One patient underwent splenectomy; 24 received bone marrow transplants. CONCLUSION: VEXAS syndrome is a rare disorder affecting predominantly middle-aged men. This is the first systematic review to capture clinical manifestations, genetics and treatment of reported cases. Further studies are needed to optimise treatment and subsequently reduce morbidity and mortality.

Sweet Syndrome as a Herpetiform Mimic: A Diagnostic Challenge.

ABSTRACT: The authors present a singular case of Sweet syndrome (acute febrile neutrophilic dermatosis) manifesting with an unusual herpetiform clinical presentation, underscoring the imperative for its inclusion in differential diagnoses of herpetic infections. A 26-year-old female patient with a systemic lupus erythematosus history presented with facial edema, hyperthermia, cephalalgia, and polyarticular pain. Dermatological examination revealed clustered, vesicle-like papules on erythematous, edematous skin, mimicking herpetic infection. Elevated acute-phase reactants and urine anomalies were noted. Histopathology confirmed Sweet syndrome, characterized by superficial and deep neutrophilic dermatitis, karyorrhexis, and papillary dermal edema. The patient responded to corticosteroid therapy and a brief antibiotic course, resolving both systemic and cutaneous symptoms. This case is remarkable for its atypical herpetiform presentation, a clinical rarity in Sweet syndrome, challenging the conventional diagnostic process. It emphasizes the necessity of considering Sweet syndrome in differential diagnoses when encountering herpetiform lesions, particularly in patients with autoimmune backgrounds. This case contributes significantly to the understanding of Sweet syndrome's clinical variability and highlights the critical role of thorough clinicopathological evaluation in achieving accurate diagnosis in complex dermatological disorders.

Neutrophilic dermatosis in a patient with an IKZF1 variant and a review of monogenic autoinflammatory disorders presenting with neutrophilic dermatoses.

Monogenic diseases of immune dysregulation should be considered in the evaluation of children presenting with recurrent neutrophilic dermatoses in association with systemic signs of inflammation, autoimmune disease, hematologic abnormalities, and opportunistic or recurrent infections. We report the case of a 2-year-old boy presenting with a neutrophilic dermatosis, found to have a novel likely pathogenic germline variant of the IKAROS Family Zinc Finger 1 (IKZF1) gene; the mutation likely results in a loss of function dimerization defective protein based on reports and studies of similar variants. IKZF1 variants could potentially lead to aberrant neutrophil chemotaxis and development of neutrophilic dermatoses. Long-term surveillance is required to monitor the development of hematologic malignancy, autoimmunity, immunodeficiency, and infection in patients with pathogenic IKZF1 germline variants.

A case of mevalonate kinase deficiency, neonatal Sweet syndrome, and inflammatory bowel disease.

Mevalonate kinase deficiency is a group of rare metabolic autoinflammatory disorders that present with recurrent fevers, abdominal pain, arthralgias, adenopathy, and a variety of cutaneous manifestations. The skin findings may mimic cellulitis, erythema elevatum diutinum, IgA vasculitis, and Sweet syndrome, and there is often a morbilliform or urticarial rash and aphthous stomatitis. Mevalonate kinase deficiency is one of the identified monogenic variants that can cause very early onset inflammatory bowel disease (IBD). We present a rare case of a patient with mevalonate kinase deficiency, neonatal Sweet syndrome, and infantile-onset IBD, who has been successfully treated with canakinumab therapy.

Mucocutaneous manifestations of inflammatory bowel disease.

Mucocutaneous manifestations can be indicative of a variety of gastrointestinal diseases, and the dermatologist needs to know how to recognize them to refer the right patients to the gastroenterologist. Conversely, the gastroenterologist is often confronted with mucocutaneous lesions that raise the question of a possible association with a known digestive disease. Among the extra-intestinal manifestations of inflammatory bowel disease (IBD), mucocutaneous manifestations are the most common. This review will provide a breakdown by classifying them into 4 groups: 1) reactive manifestations, which include neutrophilic dermatoses, aphthous stomatitis, erythema nodosum, and vasculitis; 2) Crohn's disease-specific granulomatous skin lesions, which are histologically characterized by tuberculoid granulomas similar to those found in the gastrointestinal tract; 3) nutritional deficiency manifestations secondary to anorexia, malabsorption, loss, and drug interactions; and 3) a variety of autonomous autoimmune or inflammatory skin diseases. Dermatologists may also be involved in the management of the adverse effects of IBD treatments, especially the so-called "paradoxical" psoriatic eruptions.

Somatic Mutations in UBA1 and Severe Adult-Onset Autoinflammatory Disease.

BACKGROUND: Adult-onset inflammatory syndromes often manifest with overlapping clinical features. Variants in ubiquitin-related genes, previously implicated in autoinflammatory disease, may define new disorders. METHODS: We analyzed peripheral-blood exome sequence data independent of clinical phenotype and inheritance pattern to identify deleterious mutations in ubiquitin-related genes. Sanger sequencing, immunoblotting, immunohistochemical testing, flow cytometry, and transcriptome and cytokine profiling were performed. CRISPR-Cas9-edited zebrafish were used as an in vivo model to assess gene function. RESULTS: We identified 25 men with somatic mutations affecting methionine-41 (p.Met41) in UBA1, the major E1 enzyme that initiates ubiquitylation. (The gene UBA1 lies on the X chromosome.) In such patients, an often fatal, treatment-refractory inflammatory syndrome develops in late adulthood, with fevers, cytopenias, characteristic vacuoles in myeloid and erythroid precursor cells, dysplastic bone marrow, neutrophilic cutaneous and pulmonary inflammation, chondritis, and vasculitis. Most of these 25 patients met clinical criteria for an inflammatory syndrome (relapsing polychondritis, Sweet's syndrome, polyarteritis nodosa, or giant-cell arteritis) or a hematologic condition (myelodysplastic syndrome or multiple myeloma) or both. Mutations were found in more than half the hematopoietic stem cells, including peripheral-blood myeloid cells but not lymphocytes or fibroblasts. Mutations affecting p.Met41 resulted in loss of the canonical cytoplasmic isoform of UBA1 and in expression of a novel, catalytically impaired isoform initiated at p.Met67. Mutant peripheral-blood cells showed decreased ubiquitylation and activated innate immune pathways. Knockout of the cytoplasmic UBA1 isoform homologue in zebrafish caused systemic inflammation. CONCLUSIONS: Using a genotype-driven approach, we identified a disorder that connects seemingly unrelated adult-onset inflammatory syndromes. We named this disorder the VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. (Funded by the NIH Intramural Research Programs and the EU Horizon 2020 Research and Innovation Program.).

Characterisation of IL-1 family members in Sweet syndrome highlights the overexpression of IL-1ß and IL-1R3 as possible therapeutic targets.

Sweet syndrome (SS) as a prototypic neutrophilic dermatosis (NDs) shares certain clinical and histologic features with monogenic auto-inflammatory disorders in which interleukin (IL)-1 cytokine family members play an important role. This has led to the proposal that NDs are polygenic auto-inflammatory diseases and has fuelled research to further understand the role of IL-1 family members in the pathogenesis of NDs. The aim of this study was to characterise the expression of the IL-1 family members IL-1ß, IL-36γ, IL-33 and IL-1R3 (IL-1RaP) in SS. The expression profile of IL-1ß, IL-33, IL-36γ and their common co-receptor IL-1R3 was analysed by immunohistochemistry, in situ hybridisation and double immunofluorescence (IF) in healthy control skin (HC) and lesional skin samples of SS. Marked overexpression of IL-1ß in the dermis of SS (p < 0.001), and a non-significant increase in dermal (p = 0.087) and epidermal (p = 0.345) IL-36γ expression compared to HC was observed. Significantly increased IL-1R3 expression within the dermal infiltrate of SS skin samples (p = 0.02) was also observed, whereas no difference in IL-33 expression was found between SS and HC (p = 0.7139). In situ hybridisation revealed a good correlation between gene expression levels and the above protein expression levels. Double IF identifies neutrophils and macrophages as the predominant sources of IL-1ß. This study shows that IL-1ß produced by macrophages and neutrophils and IL-1R3 are significantly overexpressed in SS, thereby indicating a potential pathogenic role for this cytokine and receptor in SS.

Neutrophilic dermatosis of the dorsal hands: A review of 123 cases.

Neutrophilic dermatosis of the dorsal hands (NDDH) is an uncommon localized variant of Sweet syndrome first described in 1995. It is characterized by tender erythematous plaques, pustules, and bullae on the dorsa of the hands. A total of 123 cases of NDDH are included in this review. The mean patient age was 62.1 years, and there was a slight female preponderance. Overall, 78.0% of cases had bilateral involvement, and other sites were affected in almost a third of cases. Underlying disease was found in ∼40% of patients, with the most common associations being hematologic disorders (gammopathies, myelodysplasias, or malignancies), recent infection, solid organ tumors, and inflammatory bowel disease. Systemic or topical corticosteroids or both were employed in the treatment of 88.1% of cases, while dapsone, colchicine, and tetracyclines were the most common steroid-sparing agents used. Improvement was often rapid and complete resolution the norm. Although uncommon, NDDH is frequently misdiagnosed, and thus, its exact prevalence is probably underestimated. Misdiagnosis might have significant implications, including treatment delays or incorrect management. Moreover, recognition of NDDH is important, since a correct diagnosis should trigger a search for underlying diseases and proper treatment with corticosteroids, steroid-sparing agents, or both, which is almost invariably curative.

Acute iododerma presenting as cryptococcoid neutrophilic dermatosis: A clinicopathological pitfall and interesting findings gleaned from a review of the literature.

Iododerma is an uncommon dermatosis caused by excessive iodine exposure and is associated with significant morbidity and mortality. Because of its heterogenous clinical presentation and variable histopathological findings, which depend on the time the skin biopsy is performed, the diagnosis of iododerma is often delayed. We report a rare case of acute iododerma in a woman with end-stage diabetic nephropathy with antecedent radioiodine contrast exposure, presenting histopathologically as cryptococcoid neutrophilic dermatosis (CND). We underscore important clinicopathological pitfalls to avoid misdiagnosis with similar overlapping entities such as Sweet syndrome, review all published cases of CND and draw novel insights into its associated entities.

Azathioprine hypersensitivity syndrome manifesting as subcutaneous Sweet syndrome and acute pancreatitis.

Azathioprine (AZA) is a commonly used immunosuppressive therapy that has been implicated in a number of cutaneous and systemic inflammatory reactions. Initiation of AZA has been associated with a hypersensitivity syndrome manifesting as acute pancreatitis and Sweet syndrome. Subcutaneous Sweet syndrome is a rare variant of Sweet syndrome where the dominant localization of inflammation is within the subcutaneous fat; it is commonly associated with underlying myeloproliferative disease. However, it has not been reported in the literature as a cutaneous manifestation of AZA hypersensitivity syndrome. We present a unique case of acute pancreatitis and biopsy-proven subcutaneous Sweet syndrome following the initiation of AZA with resolution upon discontinuation.

Neutrophilic fixed drug eruption, a histopathologic variant or an expected finding?-A report of two cases and review of the literature.

Fixed drug eruption (FDE) is an adverse drug reaction characterized by recurrent circumscribed lesions at the same location upon re-exposure to the culprit medication, resulting in distinct postinflammatory hyperpigmentation. Histopathologically, FDE demonstrates a predominantly lymphocytic interface or lichenoid infiltrate with basal cell vacuolar changes and keratinocyte dyskeratosis/apoptosis. The term "neutrophilic fixed drug eruption" has been used to describe cases in which the inflammatory infiltrate is predominantly neutrophilic. The infiltrate can extend deeper in the dermis, potentially mimicking a neutrophilic dermatosis such as Sweet syndrome. We present two cases and review the literature to discuss the possibility that a neutrophilic inflammatory infiltrate may be an expected finding in FDE, rather than a histopathologic variant.

Neoplastic or inflammatory? A case report of Sweet syndrome with CD30+ cells in a patient with B-lymphoblastic leukemia.

CD30+ cells are typically part of lymphoproliferative disorders but can also be seen in inflammatory dermatoses. We present a case of 47-year-old man with a history of B-lymphoblastic leukemia (B-ALL) who presented with fever, leukocytosis, and papulonodular skin lesions, involving the extremities and trunk. A punch biopsy specimen demonstrated papillary dermal edema with a neutrophilic and histiocytic infiltrate extending into the subcutis. The infiltrate also harbored scattered large cells that were positive for CD30 and demonstrated the immunohistochemical profile of monocytes. A diagnosis of histiocytoid Sweet syndrome with CD30+ cells was made. The case is unique, demonstrating a combination of Sweet syndrome variants with subcutis involvement, histiocytoid morphology, and large CD30+ cells. A prior history of B-ALL and immunohistochemical profile of monocytes with immature morphology broadened the differential diagnosis and added to the diagnostic challenge.

Sweet Syndrome Associated with Active Inflammatory Bowel Disease: A Case Series of a Rare Extra-intestinal Manifestation.

BACKGROUND: Cutaneous extra-intestinal manifestations (EIM) occur in up to 20% of patients with IBD. Information about Sweet syndrome (SS)'s clinical course as a rare cutaneous EIM in IBD is limited to case reports. We present the largest retrospective cohort on the occurrence and management of SS in IBD. STUDY: Electronic medical records and paper charts since 1980 were retrospectively reviewed at a large quaternary medical center to identify all adult IBD patients with histopathology-proven SS. Patient characteristics and clinical outcomes were evaluated. RESULTS: 25 IBD patients with SS were identified; 3 patients were assessed to have AZA-induced SS. The majority of SS patients were female. Median age at diagnosis was 47 years (IQR 33-54 years) and SS appeared at a median of 6.4 years after IBD diagnosis. IBD patients with SS had a high rate of complicated IBD phenotypes (75% extensive colitis in UC and 73% stricturing or penetrating disease in CD, with 100% colonic involvement), as well as frequent co-occurring EIMs (60%). SS correlated with global IBD disease activity. Corticosteroids were an effective therapy for SS in IBD. Recurrence rate of SS was 36%. CONCLUSION: Contrary to previous case reports, SS was a cutaneous EIM occurring late after diagnosis of IBD in our cohort, with occurrences paralleling global IBD disease activity. Although AZA-induced and IBD-associated SS were both effectively treated with corticosteroids, distinguishing them is relevant for future IBD treatment strategies.

Sweet Syndrome: A Review of Published Cases.

Sweet syndrome (SS), the prototypical neutrophilic dermatosis, is characterized by abrupt onset of tender plaques and nodules, classically accompanied by fever and leukocytosis. While management mainly relies on systemic corticosteroids, inadequate response can be seen in some patients that necessitates exploring other treatment options. Early diagnosis of malignancy-associated SS (MA-SS) along with detection of concomitant malignancy is crucial for improving patients' outcomes. Data regarding various clinical manifestations, extracutaneous associations, treatment, and outcomes are poorly characterized in the literature. We aimed to review all published case reports and case series to portray clinical features of SS including extracutaneous manifestations. We also describe reported treatment options and their outcomes to draw attention toward unmet therapeutic needs in the management of SS. In addition, for clinical and practical purposes, we attempted to delineate the distinction between MA-SS and nonmalignant subtypes of SS.