Abstract
A 54-year-old male smoker presented with hemoptysis. Advanced lung adenocarcinoma, cT1cN3M1b, stage IVB, was diagnosed. Enlargement of multiple intraperitoneal and inguinal lymph nodes and peripheral atypical lymphocytosis appeared after 33 cycles of second-line treatment with nivolumab, and a specimen obtained by left inguinal lymph node biopsy showed peripheral T cell lymphoma (PTCL), not otherwise specified. Lymphoma cells expressed CD3+, CD8+, and CD56+, but not CD4+ or PD-1. Despite systemic chemotherapy with cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisolone, the patient died of PTCL 864 days after the initial visit. The possible relationship between treatment with immune checkpoint inhibitors (ICIs) and PTCL development is discussed here.