縦隔に発生した髄外性形質細胞腫の1切除例

摘要

背景．髄外性形質細胞腫は形質細胞由来の比較的希な腫瘍性疾患であり，好発部位は口腔および上気道に集中しており，縦隔に発生するものは極めて希なものである．今回我々は縦隔に発生した髄外性形質細胞腫の1切除例を経験したので報告する．症例．65歳，男性．健診にて胸部レントゲンの異常陰影を指摘され，胸部CTにて腫大した縦隔リンパ節を認めた．気管支鏡下の生検では確定診断がつかず，腫瘍摘出術を施行した．腫瘍は40×45mm大で奇静脈を庄排していた．病理組織では形質細胞のびまん性増生を認め，免疫染色でIgG，kappa型の単クローン性を示し，Cyclin D1が陽性であり，髄外性形質細胞腫と診断した．結論．縦隔に発生した髄外性形質細胞腫は文献的にみても数少なく極めて希な症例であると考えられた．切除術後9ヶ月の現在，再発及び多発性骨髄腫への転化は認めていない．Background. Extramedullary plasmacytomas are rare neoplasms among plasma cell tumors and occur mainly in the upper respiratory tract or oral cavity. Such tumors limited to the mediastinum are extremely rare. Case. A 65-year-old man consulted our hospital due to a mediastinal tumor revealed on chest X-rays and computed to mography (CT). Bronchoscopic needle biopsy failed to enable a definitive diagnosis. The mediastinal tumor was completely resected. The completely encapsulated tumor was 40*45 mm. Neither trachea nor the great vessels were involved. Histopathological findings revealed plasmacytoma producing a monoclonal IgG kappa component and positive for Cyclin Dl on immunohistochemical staining. At 8 months after surgery, the patient remains well, and there is no evidence of recurrence or development of multiple myeloma. Conclusion. Solitary extramedullary plasmacytoma occurring in the mediastinum is extremely rare. In this paper, we report a surgically treated case of extramedullary plasmacytoma occurring in the mediastinum.