ペムブロリズマブ治療中に血清反応陰性関節リウマチと診断された腎盂癌

　64歳男性．右腎盂癌リンパ節転移に対して全身化学療法施行後に根治術およびリンパ節郭清術を施行．追加化学療法施行後の経過観察中に残存傍大動脈リンパ増大を認めた．抗PD-1抗体治療導入後に多発関節痛が出現し，関節リウマチと診断された．関節リウマチに対する治療介入後すみやかに関節症状は改善し，現在も抗PD-1抗体治療継続中である．免疫関連有害事象として血清反応陰性関節リウマチの報告例はまれであり，文献的考察を加え報告する．

Abstract

Sixty-four-year old male he visited our hospital with the chief complaint of asymptomatic gross hematuria. Based on the diagnosis of the right renal pelvic cancer with lymph node metastasis, radical surgery and para-aortic lymph node dissection were performed after systemic chemotherapy. During follow-up after the adjuvant chemotherapy, the remaining inter arteriovenous lymph became enlarged, then anti-PD-1 antibody treatment was introduced. After 4th month of anti-PD-1 antibody treatment, multiple joint pain accompanied by joint swelling appeared and was diagnosed as rheumatoid arthritis. Anti-rheumatoid arthritis treatment has improved joint symptoms, and anti-PD-1 antibody treatment is still continued. There is no relapse of joints and symptoms as well. Immune checkpoint inhibitors are known to have a variety of immune related adverse events, that require prompt and appropriate action. Rheumatoid arthritis is rarely reported as an immune-related adverse event. Here we report this case with a review of the literature (Rinsho Hinyokika 74 : 331-335, 2020).