A Multicentric Castleman disease associated with mixed warm and cold antibody-mediated AHA responsive to siltuximab.

Castleman disease (CD) is nonclonallymphoproliferative disorders defined by hypertrophy of lymph nodes. The multicentric form (MCD), in which multiple lymph node stations are involved, is not associated with HHV8 infection, but considered idiopathic, although IL-6 appears to play a central role in its pathogenesis. Here we report the case of a patient that presented with mixed AIHA and adenopathy, that was very challenging to diagnose due to very low values of hemoglobin and refractoriness of obtaining any improvement of AIHA with standard first and second lines of therapy (steroids, rituximab, immunoglobulin, erythropoietin, and cyclosporine). When we safely proceeded to lymph node biopsy, a diagnosis of MCD was established. This permitted the treatment with siltuximab, an anti-IL-6 monoclonal antibody. After only one week hemoglobin raised and he was discharged. After one year he still in remission. This case underlines the challenges in diagnosis of MCD, and the first case of response to siltuximab after the failure of rituximab to relieve mixed AIHA.