Adult-onset Still\'s disease (AOSD) stands as a perplexing condition with diverse clinical manifestations, posing significant diagnostic challenges for healthcare professionals. This case report delves into the clinical trajectory, diagnostic challenges, treatment strategies, and outcomes experienced by a 67-year-old female with AOSD. This report advocates for considering AOSD as a potential diagnosis in patients presenting with systemic inflammatory symptoms, especially when other conditions have been ruled out. It highlights the complexity of AOSD and the importance of interdisciplinary collaboration, close monitoring, and personalized treatment strategies to optimize patient outcomes.

A 51-year-old woman with fever was admitted to our hospital. A computed tomography (CT) scan showed thickened colonic walls. Colonoscopy revealed erosion in the ileum and colon. Adult-onset Still\'s disease (AOSD) was diagnosed due to a subsequent sore throat and skin rash. Following AOSD treatment, methylprednisolone pulse therapy, followed by prednisolone and cyclosporine, was initiated. Despite achieving a temporary improvement, relapse occurred with fever, abdominal pain, with worsening CT and endoscopic findings. The reappearance of a skin rash confirmed an exacerbation of AOSD. Tocilizumab treatment alleviated the symptoms and improved the endoscopic findings. Considering their correlation with the symptoms and endoscopic findings, the observed gastrointestinal lesions may be linked to AOSD.

Myocarditis is a rare complication of Coronavirus Disease 2019 (COVID-19) vaccination. We report a case of an elderly female who presented initially with acute myocarditis, fulminant heart failure, and atrial fibrillation after receiving a modified ribonucleic acid (mRNA) vaccine (BNT162b2). Unlike other patients with vaccine-induced myocarditis, she developed persistent fever, sore throat, polyarthralgia, diffuse macular rash, and lymphadenopathy. After extensive investigation, she was diagnosed with post-vaccination Adult-Onset Still\'s Disease. The systemic inflammation gradually subsided after the use of non-steroidal anti-inflammatory drugs and systemic steroids. She was discharged from hospital with stable hemodynamics. Methotrexate was subsequently given to maintain long-term remission.

We herein report a case of subcutaneous panniculitis-like T-cell lymphoma (SPTCL) resembling adult-onset Still\'s disease (AOSD). A 40-year-old woman presented with a fever, erythema, and painful subcutaneous nodules on the trunk. Laboratory data and a bone marrow analysis showed hemophagocytic syndrome. Although AOSD was suspected, based on a histopathological evaluation of the erythema, she was diagnosed with SPTCL. She was refractory to combination chemotherapy but achieved durable remission with cyclosporine monotherapy. Genetic testing revealed a homozygous HAVCR2 c.245A>G variant (rs184868814) that had caused NLRP3 inflammasome activation. SPTCL and AOSD share a pathogenesis in terms of NLRP3 inflammasome activation, so the clinical phenotype of SPTCL reasonably mimics AOSD.

Adult-onset Still\'s disease (AOSD) is a polygenic systemic autoinflammatory disease which is associated with increased morbidity and mortality. Pulmonary involvement is a rare, but serious complication of AOSD. As in AOSD, IL-1b, IL-18, and IL-6 dominate the molecular pathogenesis, which mediate a type 1 and type 3 inflammatory signature of the adaptive immune system. This is evidenced by the success of IL-1- and IL-6 inhibition in the management of AOSD. However, anaphylactic reactions to treatment with IL-1- or IL-6-inhibitors is currently being discussed as a potential trigger for lung involvement inf AOSD, while genetic risk factors have also been identified. Clinically, pulmonary involvement in AOSD can manifest in many different forms. Parenchymal inflammation with peripheral consolidations is the most frequent form while PAH is less common, but often very difficult to manage. This mini-review provides an overview of the pathophysiology as well as the clinical presentation and the diagnostic features of pulmonary involvement in AOSD.

Adult-onset Still\'s disease (AOSD) is a rare, systemic inflammatory disorder of not completely understood etiology. Aberrant activation of the innate immune system and overproduction of several pro-inflammatory mediators are considered a critical component in disease pathogenesis. AOSD still poses a challenge due to the broad range of differential diagnoses and no specific biomarkers. Four cardinal symptoms are quotidian spiking fever, joint involvement, evanescent salmon pink-rash rash, and leukocytosis with neutrophilia. We present a case of a 61-year-old female with a recurrent urticarial rash accompanied by attacks of high fever, tender joints, sore throat, enlarged liver, elevated inflammatory reactants, and hyperferritinemia. After an extensive workup, the patient fulfilled the criteria of AOSD. She was refractory to the glucocorticosteroids and disease-modifying anti-rheumatic drugs (DMARDs). Finally, after several unsuccessful attempts to achieve disease control with traditional DMAR\'s administration of Tocilizumab (TCZ), a humanized anti-IL-6 receptor antagonist resulted in substantial disease improvement. Since skin manifestations are a common feature of AOSD, it should be among differential diagnoses in patients with skin lesions and constitutional symptoms. Biologic agents represent a significant therapeutic advance in patients with AOSD refractory to conventional therapy.