Persistence of pulmonary infiltrates despite effective anti-infective therapy as a diagnostic clue for pembrolizumab-induced pneumonitis: a case report
Abstract
IntroductionPembrolizumab-based bladder preservation strategies are increasingly applied in invasive high-grade urothelial carcinoma, yet checkpoint inhibitor pneumonitis (CIP) remains an underrecognized, potentially fatal adverse event. Diagnosis can be markedly delayed when concurrent infection is present.Case presentationA 63-year-old man with invasive high-grade urothelial carcinoma developed complete tumor response after receiving disitamab vedotin plus pembrolizumab following chemotherapy intolerance. He subsequently presented with urinary tract infection and septic shock. Aggressive anti-infective and hemodynamic support promptly reversed shock and normalized systemic inflammatory markers. Nevertheless, follow-up chest computed tomography demonstrated persistent bilateral ground-glass opacities and consolidation without any improvement. Pre-treatment chest radiography had been normal, positron emission tomography–computed tomography showed marked bilateral pulmonary fluorodeoxyglucose uptake without bladder recurrence, and extensive microbiological workup excluded uncontrolled infection. The dissociation between well-controlled infection and stationary pulmonary lesions, together with typical imaging features, raised strong suspicion of pembrolizumab-induced CIP.ConclusionIn patients receiving PD-1 inhibitors, persistent pulmonary infiltrates despite effective anti-infective therapy should raise strong suspicion of checkpoint inhibitor pneumonitis and prompt dedicated diagnostic evaluation. This phenotype—the dissociation between resolving systemic infection and stationary lung lesions—may serve as a practical clue to consider CIP earlier, particularly when invasive diagnostic tools are unavailable; however, it is a suggestive rather than confirmatory finding and requires validation in larger cohorts.
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BibTeX
@article{zhao2026persistence,
title = {{Persistence of pulmonary infiltrates despite effective anti-infective therapy as a diagnostic clue for pembrolizumab-induced pneumonitis: a case report}},
author = {Li Zhao and Yeming Wang},
journal = {Frontiers in Oncology},
year = {2026},
month = nov,
doi = {10.3389/fonc.2026.1898019},
url = {https://www.frontiersin.org/articles/10.3389/fonc.2026.1898019},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Persistence of pulmonary infiltrates despite effective anti-infective therapy as a diagnostic clue for pembrolizumab-induced pneumonitis: a case report
AU - Li Zhao
AU - Yeming Wang
PY - 2026
DA - 2026/11/06
JO - Frontiers in Oncology
DO - 10.3389/fonc.2026.1898019
UR - https://www.frontiersin.org/articles/10.3389/fonc.2026.1898019
AB - IntroductionPembrolizumab-based bladder preservation strategies are increasingly applied in invasive high-grade urothelial carcinoma, yet checkpoint inhibitor pneumonitis (CIP) remains an underrecognized, potentially fatal adverse event. Diagnosis can be markedly delayed when concurrent infection is present.Case presentationA 63-year-old man with invasive high-grade urothelial carcinoma developed complete tumor response after receiving disitamab vedotin plus pembrolizumab following chemotherapy intolerance. He subsequently presented with urinary tract infection and septic shock. Aggressive anti-infective and hemodynamic support promptly reversed shock and normalized systemic inflammatory markers. Nevertheless, follow-up chest computed tomography demonstrated persistent bilateral ground-glass opacities and consolidation without any improvement. Pre-treatment chest radiography had been normal, positron emission tomography–computed tomography showed marked bilateral pulmonary fluorodeoxyglucose uptake without bladder recurrence, and extensive microbiological workup excluded uncontrolled infection. The dissociation between well-controlled infection and stationary pulmonary lesions, together with typical imaging features, raised strong suspicion of pembrolizumab-induced CIP.ConclusionIn patients receiving PD-1 inhibitors, persistent pulmonary infiltrates despite effective anti-infective therapy should raise strong suspicion of checkpoint inhibitor pneumonitis and prompt dedicated diagnostic evaluation. This phenotype—the dissociation between resolving systemic infection and stationary lung lesions—may serve as a practical clue to consider CIP earlier, particularly when invasive diagnostic tools are unavailable; however, it is a suggestive rather than confirmatory finding and requires validation in larger cohorts.
SN - 2234-943X
ER -