Multicentric Castleman's disease mimicking adult-onset Still's disease.

Castleman's disease is a rare lymphoproliferative disorder having two types of presentation: the localized and the multicentric form. Multicentric Castleman's disease (MCD) typically presents with constitutional symptoms, generalized peripheral lymphadenopathy, hepatosplenomegaly, and laboratory markers of inflammation. Rash and arthritis may also be initial complaints of this disease. In these cases, MCD can resemble adult-onset Still's disease (AOSD), especially if the arthritis precedes other manifestations. We describe a patient with initial clinical suspicion of AOSD. Eighteen months later evidence of MCD was ascertained when the patient developed insidiously growing axillary lymphadenopathies. Despite its rarity, MCD should be borne in mind in the differential diagnosis of patients with suspicion of AOSD.