Evaluation of clinical biomarkers for differential diagnosis of intravascular lymphoma and Still's disease.

Intravascular lymphoma (IVL) and Still's disease are rare conditions that present with overlapping systemic symptoms, including persistent fever and inflammatory responses, making differential diagnosis challenging. Misdiagnosis can lead to delays in appropriate treatment, which is particularly critical for IVL due to its aggressive nature. This retrospective cohort study aimed to identify clinically useful biomarkers for distinguishing IVL from Still's disease. IVL and Still's disease patients were analyzed alongside healthy controls. Laboratory assessments included serum ferritin, soluble interleukin-2 receptor (sIL-2R), and interleukin-18 (IL-18) levels. Ferritin levels were significantly higher in Still's disease, while sIL-2R levels were markedly elevated in IVL. IL-18 levels were significantly higher in Still's disease than in IVL, distinguishing the inflammatory profile of each disease. Receiver operating characteristic curve analysis demonstrated excellent discriminatory power, with sIL-2R and IL-18 achieving an area under the curve. These findings suggest that ferritin, sIL-2R, and IL-18 serve as potential biomarkers in differentiating IVL from Still's disease. Their incorporation into clinical practice may facilitate early and accurate diagnosis, reducing the risk of misdiagnosis and improving patient outcomes. Further large-scale studies are warranted to validate these results.