Adult-Onset Still's Disease With Extensive Lymphadenopathy Mimicking Lymphoproliferative Malignancy.

Adult-onset Still's disease (AOSD), a rare systemic inflammatory disorder of unknown etiology, is considered in broad differential in patients with fever of unknown origin or unexplained lymphadenopathy. It is characterized by spiking fever, evanescent salmon-colored maculopapular rash, arthritis or arthralgia, and leukocytosis. Due to broad differentials and lack of any specific diagnostic tests, diagnosis of AOSD poses a great challenge. A concerned physician should have a high index of suspicion while dealing with patients presenting with clinical symptoms of this systemic disorder. We report a case of a 25-year-old African American female with the past medical history of AOSD, who presented with four weeks history of extensive cervical and axillary lymphadenopathy mimicking lymphoproliferative malignancy. Cases have been reported with the development of malignant lymphoma during the course of AOSD. Therefore, careful monitoring of patients with regular follow-up is vital as these patients may develop lymphoproliferative malignancy in the future.