Evidence map›Paper›PMID 41132986›Full record

ArticleTranslational lung cancer research2025

Pseudoprogression of pleural effusion in lung cancer treated with immunotherapy: a case report.

Hiroyasu Kaneda, Lan Wang, Takako Oka, Yoko Tani, Hiroaki Nagamine, Yoshiya Matsumoto, Akira Sugimoto, Megumi Mizutani, Tatsuo Kimura, Tomoya Kawaguchi

Abstract readCase Reports
In one paragraph

Article in Translational lung cancer research, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Pulmonary toxicity of immune checkpoint inhibitors.Breathe (Sheffield, England) · 2026
    Review
4 · The record

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5 · Who and what money

Authors and funding

10 authors.

Hiroyasu KanedaDepartment of Clinical Oncology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.ORCID https://orcid.org/0000-0002-7696-2391
Lan WangDepartment of Respiratory and Critical Care Medicine, The Fourth Affiliated Hospital of Soochow University, Suzhou Dushu Lake Hospital, Suzhou, China.
Takako OkaDepartment of Clinical Oncology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Yoko TaniDepartment of Clinical Oncology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Hiroaki NagamineDepartment of Respiratory Medicine, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Yoshiya MatsumotoDepartment of Respiratory Medicine, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Akira SugimotoDepartment of Respiratory Medicine, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Megumi MizutaniDepartment of Respiratory Medicine, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Tatsuo KimuraDepartment of Premier Preventive Medicine, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Tomoya KawaguchiDepartment of Clinical Oncology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: Pseudoprogression (PsP) is an atypical response phenomenon increasingly recognized in patients treated with immune checkpoint inhibitors (ICIs), characterized by transient radiologic worsening before subsequent tumor regression. This response pattern complicates the interpretation of treatment efficacy and poses a challenge in distinguishing true disease progression from a treatment-related immune effect. While PsP is most commonly observed as an initial increase in tumor size or the appearance of new lesions, its presentation as pleural effusion is exceedingly rare and may be misdiagnosed as disease progression or immune-related adverse events (irAEs). Prompt recognition of this phenomenon is essential to avoid premature discontinuation of potentially effective therapy. Case Description: Here, we report a rare case of PsP manifesting as pleural effusion in a 56-year-old woman with lung adenocarcinoma and pleural dissemination who was treated with first-line pembrolizumab. Three weeks after treatment initiation, the patient developed new pleural effusion without accompanying symptoms. Pleural fluid analysis revealed adenocarcinoma cells with a predominance of lymphocytes. Despite the cytological findings, the patient's clinical stability and subsequent imaging demonstrated spontaneous resolution of the effusion and regression of disease with continued ICI therapy. The pleural effusion did not recur, and the patient remained on pembrolizumab for over 1 year until eventual progression. Conclusions: This case highlights that PsP can manifest as new-onset pleural effusion, even in the presence of malignant cells in pleural fluid. Clinicians should be aware of this rare presentation, especially when the patient remains clinically stable. Differentiating PsP from irAEs and true progression remains challenging and emphasizes the need for improved biomarkers to guide decision-making. Continuation of ICIs may be appropriate in selected patients with manageable pleural effusion and controlled tumor burden, as inappropriate discontinuation could forfeit potential therapeutic benefit.

Indexed as

case reportImmune checkpoint inhibitors (ICIs)lung cancerpleural effusionpseudoprogression (PsP)

Identifiers

PMID41132986
PMCPMC12541859

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