Lung Adenocarcinoma with Paraneoplastic Hyper-Eosinophilia Not Responding To Pembrolizumab

Abstract

Background: Paraneoplastic hyper-eosinophilia associated with metastatic lung adenocarcinoma is a rare finding and has been associated with a poor prognosis when present. Early hyper-eosinophilia appearing following non-small cell lung cancer (NSCLC) treatment with immune checkpoint inhibitors (ICI) has been previously reported with contradictory outcomes.

Case summary: We present the case of an elderly man with newly diagnosed metastatic lung adenocarcinoma and baseline hyper-eosinophilia, treated with pembrolizumab, and showing evidence of significant and rapid disease progression suggestive of hyper-progressive disease, worsening baseline hyper-eosinophilia, and a fatal outcome within 1 month of therapy initiation.

Conclusion: Pre-treatment hyper-eosinophilia could represent a predictive factor of an unfavorable response to ICI treatment in cases of NSCLC. Additional similar cases are needed to draw a more conclusive relationship.

Keywords: Immunotherapy; adenocarcinoma of lung; eosinophilia; neoplasm metastasis; neoplasms; pleura.

Figure 1.

Positron emission tomography (December 4th) showing disease involvement of left lung, left pleura, mediastinal, and left lung hilar lymph nodes and left adrenal gland.

Figure 2.

Baseline chest computed tomography done on December 1st (left) and follow up imaging on December 15th (right) with evident increase in the size of the left lower lobe consolidation and multiple left pleural-based masses.

Figure 3.

December 17th: Imaging pre (left) and post (right) bronchoscopy, 12 days after pembrolizumab dose, showing complete left hemi-thorax opacification and confirmed by pathology to be tumor hyper-progression.

Figure 4.

Baseline eosinophilia before and after administration of pembrolizumab. Abbreviation: AEC, absolute eosinophils count. The dates in squares represent the first and second pembrolizumab doses.