Abstract
A 73-year-old Japanese woman with productive cough and dyspnoea on exertion was admitted, and she showed neutropenia and pulmonary reticular opacities and axial and mediastinal lymphadenopathies on chest computed tomography. The clinical findings and surgical lung and lymph node biopsies were diagnostic for idiopathic multicentric Castleman's disease (iMCD) complicated by secondary autoimmune neutropenia (AIN). iMCD is often complicated with hematologic disorders, however, iMCD complicated with AIN has not been reported; therefore, if iMCD is accompanied by neutropenia, the anti-neutrophil antibodies should be measured.