Pleural effusion or ascites complicating plasmacytoma is rare and has a poor prognosis. A 70-year-old man was diagnosed as plasma cell leukemia and one course of ranimustine-vindesine, melphalan, and prednisolone followed by melphalan and prednisone (MP) maintained a very good partial response. After MP he was diagnosed to have pleural effusion and ascites as a complication of the plasmacytoma. Low-dose bortezomib caused disappearance of the malignant effusion. The malignant effusions recurred after the end of the second course of bortezomib. High-dose dexamethasone vincristine, doxorubicin, cyclophosphamide, and prednisone yielded no benefit, the patient died of Aspergillus pneumonia.