The Successful Treatment of Pulmonary Pleomorphic Carcinoma with Pembrolizumab: A Case Report.

Pulmonary pleomorphic carcinomas are rare malignant tumors, and no standard treatments have been established. We herein report the successful treatment of a patient with pulmonary pleomorphic carcinoma with pembrolizumab. A 51-year-old man who was a current smoker presented to our hospital due to dyspnea and hemosputum. Chest X-ray showed right-sided pneumothorax with pleural effusion; chest tube drainage was therefore performed. Computed tomography after chest tube drainage showed a cavitary nodule in the right upper lobe and right hilar and bilateral mediastinal lymphadenopathy. Surgery was performed for the diagnosis and treatment. He was eventually diagnosed with pulmonary pleomorphic carcinoma corresponding to clinical stage IVB (cT2aN2M1c [PLE, ADR, HEP]). The giant cells strongly expressed programmed death ligand-1, and the tumor proportion score was more than 50%. Therefore, pembrolizumab was introduced as the first-line therapy. After 3 cycles of pembrolizumab, his right hilar and bilateral mediastinal lymphadenopathy and pleural dissemination notably decreased. Pembrolizumab might be an effective therapy for pulmonary pleomorphic carcinoma.