A Case of Idiopathic Multicentric Castleman's Disease Diagnosed From Anemia and Renal Dysfunction on an Annual Check-Up.

A 34-year-old man was referred to our hospital because of mild renal dysfunction and anemia. He had no specific preexisting medical conditions; his complaint was fatigue. Physical examination revealed several mobile, pinky head-sized (no tenderness) palpable lymph nodes on the bilateral neck. Blood biochemistry tests revealed anemia, renal dysfunction, increased inflammation, and a protein-albumin discrepancy. Immunological examination revealed polyclonal elevation of immunoglobulins (no shift in κ/λ ratio). A cervical lymph node biopsy was performed, and the pathological results showed numerous clusters of mature plasma cells (plasmacytic type), leading to the definitive diagnosis of idiopathic multicentric Castleman's disease (iMCD).