Livedoid vasculopathy (LV) is a rare, chronic vascular disorder marked by painful, recurrent ulcerations that primarily affect the lower extremities. It is frequently associated with hypercoagulable states, although its pathophysiology remains incompletely understood. We present the case of a 25-year-old woman with a longstanding history of LV, elevated factor VIII, increased lipoprotein(a), recurrent kidney stones, and iron deficiency anemia who presented with worsening lower-extremity ulcerations. An extensive workup excluded other hypercoagulable and connective-tissue conditions, leaving elevated factor VIII and lipoprotein(a) as the most likely contributors to her disease. Although her symptoms initially resolved with treatment, they recurred over time, and management was further complicated by her desire for future pregnancy, which precluded the use of several standard anticoagulant therapies. Her regimen was ultimately centered on pentoxifylline and low-dose aspirin to control symptoms while minimizing risk to a future pregnancy. This case illustrates the importance of individualized treatment planning in LV, particularly when hypercoagulable risk factors intersect with reproductive goals.

Kawasaki disease (KD) is an acute vasculitis that primarily affects the pediatric population, with coronary artery lesions constituting its most severe clinical sequela. Although investigated for decades, the precise etiology and pathogenesis of this syndrome remain elusive. This critical knowledge gap stems from the absence of robust in vitro platforms capable of accurately recreating the complex pathophysiological dynamics of pediatric coronary arteries. To overcome this challenge, we developed hollow hydrogel fibers using microfluidic coaxial printing, which were then seeded with human coronary artery smooth muscle cells (HCASMCs) and human umbilical vein endothelial cells (HUVECs) to generate a biomimetic coronary artery construct. The physiological responsiveness of the model was validated through stimulation with TNF-α, and a KD-specific pathological model was established by introducing serum from KD patients. Using this biomimetic platform, we evaluated the therapeutic potential of Atorvastatin (ATOR) and the NLRP3 inflammasome inhibitor MCC950, and explored their underlying mechanisms in attenuating vascular inflammation. Overall, this work introduces a structurally relevant in vitro platform that offers new opportunities for studying KD pathogenesis and accelerating the development of targeted therapies.

A girl in the first decade of life presented with a 1.5 year history of gradually progressive bilateral upper eyelid swelling with bilateral proptosis, more prominent on the right side. She had a partial response to oral prednisolone, but symptoms recurred during tapering. Examination showed firm bilateral upper eyelid masses, preserved vision and mild restriction of upward gaze in the right eye. MRI demonstrated right preseptal/periorbital soft tissue thickening. Further evaluation excluded infection, vasculitis, sarcoidosis and malignancy; serum IgG4 level was normal. Biopsy of the right eyelid lesion showed concentric perivascular fibrosis with eosinophil-rich lymphoplasmacytic infiltrate, consistent with eosinophilic angiocentric fibrosis, supporting a diagnosis of possible organ-limited IgG4-related disease. The patient was treated with oral prednisolone and mycophenolate mofetil, resulting in sustained clinical improvement. This case highlights that paediatric IgG4-related disease may present as isolated orbital swelling with normal serum IgG4, making histopathology crucial for diagnosis.

Clostridium septicum is an aerotolerant anaerobe classically linked to occult colorectal malignancy and hematologic disease, and a rare but frequently fatal cause of nontraumatic infective aortitis; it also causes gas gangrene, osteomyelitis and spondylodiscitis. Survival depends on radical surgical debridement, as antibiotics alone are almost uniformly fatal. We describe a 71-year-old man with untreated chronic myelomonocytic leukemia (CMML) who presented with back pain, vomiting and rigors. Computed tomography showed perforated appendicitis with extraluminal air together with mediastinitis and aortitis of the aortic arch and the aorta at the diaphragmatic hiatus. Inflammatory markers were markedly elevated and vasculitis serologies negative. The appendix was managed nonoperatively as he remained hemodynamically stable. Despite broad-spectrum antibiotics, repeat angiography on day 5 showed new aneurysmal dilatation of the arch to 5.1 cm, prompting emergent left carotid-subclavian bypass and thoracic endovascular aortic repair. On day 8, thoracotomy revealed necrotic aortic wall with an exposed endograft, which was debrided and covered with a pedicled latissimus dorsi flap; tissue cultures grew C. septicum. Colonoscopy twelve months earlier had shown only polyps and diverticulosis. He completed six weeks of intravenous ampicillin-sulbactam, was transitioned to lifelong oral suppression for retained prosthetic material, and was discharged on day 57 to long-term acute care, ventilator-dependent. This case shows that C. septicum aortitis may arise from a perforated appendix rather than a colorectal neoplasm, that nonoperative appendicitis management may give inadequate source control in an immunocompromised host, and that survival is attainable with a staged hybrid endovascular-and-open strategy.

Granulomatosis with polyangiitis (GPA) is a subtype of ANCA-associated vasculitis that can have a heterogeneous clinical presentation. Although classically involving the respiratory tract and kidneys, GPA can rarely present with predominant skeletal muscle involvement. This is unique given that skeletal muscle involvement has predominantly been associated with eosinophilic GPA and microscopic polyangiitis in the literature. Here, we detail a patient who presented with acute, progressive bilateral proximal lower extremity weakness and thigh pain, along with weight loss and transiently elevated creatine kinase and aldolase. The clinical course was complicated by temporally distinct focal cerebral infarctions, alongside findings of rhinosinusitis and multiple pulmonary nodules. Serology was positive for PR3-ANCA antibodies, and magnetic resonance angiography of the brain utilising black blood sequence confirmed central nervous system (CNS) vasculitis. Crucially, targeted biopsies of the right vastus lateralis and lung nodule demonstrated fibrinoid necrosis and necrotizing granulomatous inflammation, respectively. Together, this histopathological evidence strongly suggests the proximal myopathy and CNS infarction as the result of profound, systemic microvascular ischaemia. This case highlights that GPA may initially manifest as muscle weakness. Recognising this atypical presentation is crucial to ensure timely initiation of treatment to reduce disease-associated morbidity and mortality.

Pyrexia of unknown origin (PUO) in children presents a significant diagnostic challenge owing to its broad and heterogeneous aetiology. Among autoimmune causes, childhood-onset Takayasu arteritis (cTAK) is rare but clinically critical, typically characterised by non-specific constitutional symptoms and diagnosed late. Conventional angiographic imaging depicts structural vascular changes and may fail to identify the disease in its early, pre-stenotic inflammatory phase. We evaluated the role of 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging ([18]F-FDG-PET/MR) in the early detection of pre-stenotic cTAK in children presenting with PUO and its impact on management and short-term outcomes. In this single-centre, retrospective descriptive case series conducted over 2 years, children (≤18 years) presenting with PUO who underwent [18]F-FDG-PET/MR and were subsequently diagnosed with pre-stenotic Takayasu arteritis (paediatric European League Against Rheumatism/Paediatric Rheumatology International Trials Organisation/Paediatric Rheumatology European Society 2008 criteria) were analysed. During the study period, 28 children with PUO underwent [18]F-FDG-PET/MR; 7 (25%) were diagnosed with pre-stenotic cTAK (mean age 13.9 years; 5 girls), and of the remaining 21, 20 received alternative diagnoses. All had constitutional symptoms and markedly elevated inflammatory markers (mean ESR of 104 mm/h; mean C-reactive protein of 128.4 mg/L), with infrequent overt vascular signs. [18]F-FDG-PET/MR demonstrated FDG-avid wall thickening of the aorta and its major branches in every patient (maximum standardised uptake value 2.7-7.4; median 4.8), without haemodynamically significant stenosis at baseline. All children received pulsed methylprednisolone, oral prednisolone, and mycophenolate mofetil; three required tocilizumab and one adalimumab. Over a median follow-up of 20 months (range 9-36), one child developed a short-segment left subclavian stenosis, while the remainder showed no new structural progression, occlusion, or pulseless features. [18]F-FDG-PET/MR detected metabolically active large-vessel inflammation in the pre-stenotic phase, enabling early diagnosis and treatment. These preliminary, hypothesis-generating findings support further investigation of [18]F-FDG-PET/MR in selected children with PUO and persistent inflammation; prospective, multicentre validation with standardised paediatric protocols and longer follow-up is required before routine integration into diagnostic pathways.

IgA vasculitis (IgAV), a small-vessel systemic vasculitis characterised by arthritis, renal involvement and palpable purpura without thrombocytopenia, predominantly affects children and is rare in adults. Immunosuppressive treatment is typically reserved for significant renal involvement or refractory abdominal and joint pain. However, therapeutic targets for gastrointestinal involvement remain poorly defined. A man in his 20s with no medical history presented with weeks of abdominal pain, post-prandial vomiting, purpuric rash, arthralgia and hypertension. Urine studies showed subnephrotic range proteinuria and colonoscopy revealed ileal ulceration. Immunofluorescence of skin, ileal and renal biopsies demonstrated perivascular IgA deposition, confirming IgAV. Although renal involvement did not necessitate treatment, recurrent severe gastrointestinal symptoms and biochemical evidence of liver involvement prompted a 6-week course of oral prednisone following multidisciplinary consultation. His symptoms resolved, with complete normalisation of renal function and liver enzymes.

This case presents a female in her 20s with biopsy-confirmed cutaneous leukocytoclastic vasculitis (LCV) and significant gastrointestinal (GI) symptoms, manifesting as recurrent rectal bleeding, abdominal pain and maculopapular rash. The patient's symptoms emerged shortly after treatment with phenoxymethylpenicillin for tonsillitis. Investigations revealed left-sided colitis with distinctive endoscopic findings. Skin biopsy confirmed cutaneous LCV; however, colonic biopsies demonstrated non-specific inflammation without histological evidence of vasculitis. Therefore, GI vasculitic involvement could not be confirmed. Negative autoimmune serology excluded primary autoimmune disorders. Following treatment with prednisolone and mesalazine, the patient's symptoms resolved and she showed sustained improvement. While clinical improvement occurred after corticosteroid therapy, this response is non-specific and does not confirm GI vasculitis. Given the absence of vasculitic features on GI histology, the relationship between cutaneous LCV and colitis in this case remains associative rather than proven. This case underscores the importance of diagnostic caution when extracutaneous manifestations are suspected in LCV.

Blau syndrome is a rare granulomatous autoinflammatory disease caused by NOD2 mutations and characterised by dermatitis, arthritis and uveitis. We report a middle childhood boy initially diagnosed with oligoarticular juvenile idiopathic arthritis (JIA) because arthritis was the predominant early manifestation. He had papular skin lesions in infancy and periarticular swelling and tenosynovial cysts, later developed persistent arthritis and recurrent fever. Genetic testing identified a heterozygous NOD2 variant (c.1001G>A, p.Arg334Gln [R334Q]), confirming Blau syndrome. Despite ongoing methotrexate and adalimumab therapy, routine ophthalmic examination revealed unilateral anterior uveitis with iris nodules. Fundus examination showed bilateral multifocal chorioretinal lesions, and fluorescein angiography demonstrated retinal vasculitis. Ocular inflammation became quiescent after topical corticosteroid treatment and weight-based escalation of adalimumab. This case highlights that Blau syndrome may masquerade as JIA and that regular ophthalmic surveillance remains essential even during biologic therapy.