Multicentric Castleman's disease is a polyclonal lymphoproliferative disorder. Recently, a new variant of the disease was reported and named TAFRO syndrome, an acronym for thrombocytopenia, ascites, myelofibrosis, renal dysfunction, and organomegaly. A 55-year-old woman presented to our hospital with dyspnea on exertion and high fever. Laboratory tests revealed anemia, thrombocytopenia, and proteinuria. Computed tomography (CT) revealed a large anterior mediastinal mass, mild splenomegaly, bilateral pleural effusion, pericardial effusion, and mild systemic lymphadenopathy. A CT-guided biopsy was unable to establish a definitive diagnosis, so we resected the mediastinal mass for diagnostic and therapeutic purposes. Pathological findings were consistent with the hyaline vascular type of Castleman's disease (CD), and she was diagnosed with TAFRO syndrome. There has been no description of a patient with TAFRO syndrome with a large mass, and this is the first case of TAFRO syndrome treated with debulking surgery.