Abscopal effect following nivolumab induction in a patient with metastatic renal cell carcinoma-unique pathological features of the primary specimen: A case report

The case of a patient with metastatic renal cell carcinoma who exhibited the abscopal effect following treatment by anti-programmed death-1 (PD-1) antibody is presented. A 40-year-old woman was diagnosed with an 8.2-cm renal tumor without distant metastases, and radical nephrectomy was subsequently performed. Pathological examination revealed a clear cell renal cell carcinoma. At 3 months after surgery, the patient developed one lung metastasis. Following treatment with interferon and three types of tyrosine kinase inhibitors, anti-PD1 antibody (nivolumab) was started. During the treatment, para-aortic/supraclavicular lymph nodes and several lung lesions remained, although other lesions decreased markedly. The patient was subsequently treated by palliative radiotherapy to the para-aortic and supraclavicular lymph nodes for pain control. After the radiotherapy, the lung lesions previously refractory to nivolumab started to decrease, probably due to an abscopal effect. Additionally, the laboratory data and Karnofsky Performance Status improved. Histological re-examination of the primary lesion revealed heterogeneity of the immunological microenvironment, which may be associated with the heterogeneity of treatment sensitivity.