Spontaneous Regression of Pulmonary Lymphoepithelioma-Like Carcinoma.

The spontaneous regression of lung cancer is extremely rare. We encountered a case of a 70-year-old man with pulmonary lymphoepithelioma-like carcinoma that regressed without receiving anticancer therapy. The patient had depression during tumor regression, however, and was treated with a serotonin-selective reuptake inhibitor. On histologic examination, CD3(+), CD4(+), and CD8(+) lymphocytes were found to have infiltrated around the tumor. Thus, the serotonin-selective reuptake inhibitor may have activated these lymphocytes to cause spontaneous tumor regression.