Severe warm-antibody autoimmune hemolytic anemia due to multicentric Castleman disease: Responding to rituximab.

Castleman disease is a rare B-cell lymphoproliferative disorder characterized by lymph node enlargement with or without constitutional signs. Herein, we describe a unique patient with multicentric Castleman disease and retroviral infection who presented with a sudden onset of constitutional signs and was found to have severe warm-antibody autoimmune hemolytic anemia. Rituximab monotherapy yielded an excellent clinical response. We aim to inform the medical community of this rare paraneoplastic phenomenon in patients with Castleman disease and its effective management. Prompt recognition of this entity may help avoid costly diagnostic workups, excessive blood transfusions, and lengthy hospital stays.