Successfully managed combined pulmonary fibrosis and emphysema in a lung large cell neuroendocrine carcinoma patient treated with pembrolizumab

To the Editor: A 75-year-old man was referred to our division because of an appearance of tumor in the left lobe of the liver. The patient had a smoking habit and was diagnosed as having combined pulmonary fibrosis and emphysema (CPFE) 9 years ago by a respiratory function test and chest CT (Figure 1A). Then, the patient visited our hospital regularly. Chest CT taken 8 years after the first visit, a nodule appeared in the right upper lobe of the lung. He underwent right upper lobectomy and mediastinal lymph node dissection. Pathologically, the tumor was diagnosed as stage IIB large cell neuroendocrine carcinoma (LCNEC). The expression of programmed death ligand 1 tumor proportion score of the resected specimens was 25%. No adjuvant chemotherapy was performed because the patient did not wish to receive it. Fluorodeoxyglucose (FDG)/ positron emission tomography-CT scan taken 1 year after the surgical resection, a tumor with FDG uptake in the left lobe of the liver was found (Figure 2A). Physical examination was unremarkable. His modified British Medical Research Council Scale was Grade 2. The arterial oxygen saturation (SpO2) was 97% in resting room air. Although liver metastatic lesion was asymptomatic, chemotherapy, immune checkpoint inhibitor, and combination of them were proposed. The risk of pulmonary toxicity of them was also repeatedly presented. As a result, the patient selected an immune checkpoint inhibitor therapy. Pembrolizumab (200 mg/day) was started with the schedule of administration once every 3 weeks. One week after the first administration of pembrolizumab, increase in