This study investigates the development and management of lymphoproliferative lesions in organ transplant recipients treated with cyclosporin and steroids. The authors report that lymphomas or other lymphoproliferative lesions developed in 8, 4, 3, and 2 recipients of cadaveric kidney, liver, heart, and heart-lung homografts, respectively. Reducing or discontinuing immunosuppression led to regression of these lesions, often without subsequent graft rejection. Chemotherapy and irradiation were ineffective. The findings suggest that cyclosporin lymphomas are relatively benign and can be managed by appropriately reducing immunosuppression. The study highlights the importance of this approach in treating post-transplantation neoplasms, particularly in liver and cardiac recipients, despite the risk of graft rejection.This study investigates the development and management of lymphoproliferative lesions in organ transplant recipients treated with cyclosporin and steroids. The authors report that lymphomas or other lymphoproliferative lesions developed in 8, 4, 3, and 2 recipients of cadaveric kidney, liver, heart, and heart-lung homografts, respectively. Reducing or discontinuing immunosuppression led to regression of these lesions, often without subsequent graft rejection. Chemotherapy and irradiation were ineffective. The findings suggest that cyclosporin lymphomas are relatively benign and can be managed by appropriately reducing immunosuppression. The study highlights the importance of this approach in treating post-transplantation neoplasms, particularly in liver and cardiac recipients, despite the risk of graft rejection.