title: [Development of an extramedullary plasmacytoma despite disappearing M protein in multiple myeloma by bortezomib treatment].
abstract: A 65-year-old male with IgG-kappa multiple myeloma was treated with melphalan-prednisolone (MP) and obtained a minimal response. Five months after the initiation of MP, he developed back pain, renal failure, hypercalcemia and increased plasma cells in the bone marrow. He was treated with bortezomib. After 2 cycles, he developed a peripheral neuropathy, and the dose of bortezomib was decreased to 1.0 mg/m(2). After 5 cycles, serum monoclonal protein was not detected by immunofixation, and the percentage of bone marrow plasma cells decreased to less than 5%. In March 2007, he developed lumbago again, and MRI of the lumbar vertebrae showed a tumor at the para pediculus arcus vertebrae. Immunohistochemistry of the biopsied tumor demonstrated monoclonal plasma cell infiltration. The patient was treated with local radiation therapy. Bortezomib is a new and effective agent for refractory/relapsed multiple myeloma. It has also been reported that bortezomib is effective for solitary extramedullary plasmacytoma (EMP). However, in the patient reported here, although bortezomib induced a complete response with regard to the serum monoclonal protein and the percentage of bone marrow plasma cells, EMP developed in the parapediculus arcus vertebrae. Herein, we document a case of EMP development during successful bortezomib therapy.
authors.affiliation: Medicine and Clinical Science, Gunma University Graduate School of Medicine, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Koiso
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tahara
authors.forename: Yohei
authors.initials: Y
authors.lastname: Osaki
authors.forename: Momoko
authors.initials: M
authors.lastname: Mawatari
authors.forename: Tomomi
authors.initials: T
authors.lastname: Sekigami
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yokohama
authors.forename: Takayuki
authors.initials: T
authors.lastname: Saitoh
authors.forename: Hideki
authors.initials: H
authors.lastname: Uchiumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Handa
authors.forename: Norifumi
authors.initials: N
authors.lastname: Tsukamoto
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Karasawa
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Nojima
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Murakami
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D001897:Boronic Acids / Q000008:administration & dosage*; D000069286:Bortezomib; D006801:Humans; D008159:Lumbar Vertebrae; D008297:Male; D009101:Multiple Myeloma / Q000097:blood / Q000188:drug therapy*; D009194:Myeloma Proteins / Q000652:urine; D016609:Neoplasms, Second Primary / Q000209:etiology*; D010954:Plasmacytoma / Q000209:etiology*; D011480:Protease Inhibitors / Q000008:administration & dosage*; D011719:Pyrazines / Q000008:administration & dosage*; D013125:Spinal Neoplasms / Q000209:etiology*
chemical_list: D000970:Antineoplastic Agents; D001897:Boronic Acids; D009194:Myeloma Proteins; D011480:Protease Inhibitors; D011719:Pyrazines; C085016:multiple myeloma M-proteins; D000069286:Bortezomib