Salvage Surgery for Lesions Resistant to Immune Checkpoint Inhibitors in a Case Suggestive of Pulmonary Pleomorphic Carcinoma

Pulmonary pleomorphic carcinoma, a rare chemoresistant sarcomatoid lung cancer, responds to immune checkpoint inhibitors (ICIs). ICIs are effective when programmed death-ligand 1 (PD-L1) expression is high. We treated a 61-year-old man with pembrolizumab whose spindle cell carcinoma regressed. However, salvage resection of a slowly enlarging residual nodule revealed adenocarcinoma, prompting a reconsideration of the entire clinical course. The lesion was ultimately considered suggestive of pulmonary pleomorphic carcinoma, underscoring the pronounced intratumoral heterogeneity with variable ICI sensitivity. When durable disease control is achieved with ICIs in pulmonary pleomorphic carcinoma, this heterogeneity should prompt consideration of local therapies, particularly surgical excision, for recurrent foci.