Bilateral Testicular Metastases from Lung Adenocarcinoma Showing an Objective Response to Nivolumab: A Case Report and Review of the Literature

A 69-year-old man who had undergone chemoradiotherapy for advanced pulmonary adenocarcinoma had bilateral testicular and adrenal gland masses on a routine follow-up examination. We performed left orchiectomy, and the histopathological examination confirmed metastatic pulmonary adenocarcinoma involving the extracted testis. He was treated for disease progression with nivolumab after unsuccessful cytotoxic chemotherapy, which resulted in regression of recurrent adrenal and right testicular tumors. We reviewed the existing literature on metastatic testicular tumors and found that testicular metastasis from lung cancer is rare and poses a chemotherapeutic challenge. Based on our experience, immune checkpoint inhibitors seem to have good efficacy for treating testicular metastasis.