早期髄外性胃形質細胞腫の1例

Extramedullary Gastric Plasmacytoma at an Early Stage, Report of a Case

要旨　患者は50歳，男性．特に自覚症状なく胃集検を受診し，胃角変形を指摘されて当センターを受診する．胃内視鏡検査で胃角大彎に小退色帯，および軽度の凹凸不整が認められた．生検組織所見では，小退色帯の部分よりIgA/λでmonoclonalに陽性の針状結晶物質が，粘膜固有層にほぼびまん性にわたり認められ，形質細胞腫と診断された．切除標本では，粘膜固有層にびまん性に腫瘍性の形質細胞が認められた．胃形質細胞腫は，現在までに欧米で約100例，本邦では自験例を含め41例報告されているが，進行例が多い．本例は病変が粘膜内に限局し，肉眼的にも軽微な変化で，早期の段階のものと思われる．

　A 50-year-old male, asymptomatic, was pointed out at mass survey that the gastric angle was deformed. Subsequently performed endoscopic examination showed slightly coarse, uneven areae gastricae and a portion with whitish discoloration along the greater curvature. Biopsy specimen included spindle-shaped crystals in the extensive area of the lamina propria. These crystals were monoclonally positive for IgA/λ, leading to the definitive diagnosis of plasmacytoma. Resected specimen of the stomach showed microscopically neoplastic growth of plasma cells in the extensive area of the lamina propria.

　About 100 cases of piasmacytoma have been reported so far in Europe and the U.S., whereas those in Japan were 41 cases including the present one. Most of the reported cases were at advanced stages. The present case in which the lesion was confined only to the mucosal layer was considered to be at an earlier stage.