Right Small Cell Lung Cancer Progressing During Pembrolizumab

What happened, in summary

A 72-year-old man with a long smoking history had masses in both lungs. The right upper-lung mass arose within a giant bulla, making biopsy risky. The left mass was confirmed as adenocarcinoma, so pembrolizumab was started for the overall bilateral presentation. Clinicians had considered the possibility of separate primary lung cancers, but the right tumor had not yet been sampled.

While the left tumor rapidly shrank, the right upper-lung mass continued to enlarge. Fluid accumulated within the bulla and then around the right lung. Antibiotics were given for a possible infection and steroids for a possible chronic-obstructive-lung-disease flare or pseudoprogression, but the tumor kept growing. Drainage of the pleural effusion showed malignant cells characteristic of small cell lung cancer.

His general condition deteriorated rapidly, and he died on March 8, 2018. Autopsy confirmed that the right upper-lung tumor was small cell lung cancer and found additional small cell-type lesions in the liver. The final diagnosis was synchronous primary lung cancers: right-sided small cell lung cancer and a separate left-sided adenocarcinoma.