腹膜播種を有する腎移植後小腸悪性リンパ腫に対して腹腔鏡補助下切除，化学療法により完全寛解となった1例

Disseminated malignant lymphoma of the small intestine after kidney transplantation : complete remission obtained by laparoscopy-assisted resection and chemotherapy

◆要旨：患者は46歳の男性で，生体腎移植術の7年後に腹部に疝痛を生じ，CTで回盲部の腫瘍と多数の腹腔内結節を指摘された．移植後リンパ増殖性疾患を疑い免疫抑制剤を減量したが，腫瘍は縮小しなかったため，腹腔鏡補助下回盲部切除術を施行した．回盲部の手拳大の腫瘍と腸間膜や腹膜の多数の腫瘍性結節を認め，腹水細胞診はリンパ腫細胞陽性であった．組織学的にびまん性B細胞性リンパ腫でEpstein-Barr virusは検出されなかった．術後化学療法を8コース行ったところ，腹腔内に多数残存していた結節性病変は消失した．自験例は腹膜播種を伴っていたが術後早期に化学療法を行うことにより良好な治療結果を得ることができた．

　We report a case of post-transplant lymphoproliferative disease（PTLD）after living donor renal transplantation. A 46-year-old male, who had undergone renal transplantation 7 years ago, presented with abdominal colic pain. CT scan revealed a mass lesion in the terminal ileum and many small nodules in the peritoneal cavity. Under the tentative diagnosis of PTLD, his immunosuppression medication was dramatically decreased, which resulted in tumor growth. Thus we performed laparoscopy-assisted ileocecal resection. The tumor was located in the terminal ileum and many disseminated nodules were noted in the peritoneal cavity. The pathological diagnosis was diffuse B cell lymphoma, which was positive for CD 20, but negative for Epstein-Barr virus（EBV）related proteins. Postoperatively, he received 8 courses of chemotherapy（R-CHOP; rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone）and achieved complete remission. This case was a typical presentation of EBV negative PTLD occurring in a late phase after transplantation. Although the tumor had already been in an advanced stage on diagnosis, we successfully treated the patient with a combination of surgery and chemotherapy.