case_images: PMC11260777_01
case_images: Initial tumor response of nivolumab (partial response). (A) CT revealed a primary lesion in right upper lobe and metastases of left adrenal gland before nivolumab. (B) Primary lesion and adrenal gland metastasis shrunk after 2 months of nivolumab.
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case_images: CT image showed a pulmonary metastasis lesion in the right upper lobe and the left adrenal gland were enlarged ( Figure 1A ). After initiation of nivolumab, the right upper lobe lesion and adrenal metastasis shrunk rapidly ( Figure 1B ), and his tumor markers decreased ( Figure 2 ).
case_images: First late-phase pseudo-progression after 1-year of nivolumab. After 7-months of nivolumab, tumor markers increased. CT scan at 1-year showed swollen mediastinal lymph node (LN, short axis 15 mm, 1st pseudo-progression; new measurable LN lesion), PET-CT scan revealed a high-level uptake of the mediastinal LN. At 2-years, the mediastinal LN shrunk significantly (short axis 4 mm).
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case_images: After initiation of nivolumab, the right upper lobe lesion and adrenal metastasis shrunk rapidly ( Figure 1B ), and his tumor markers decreased ( Figure 2 ). However, 7 months later, the patient's tumor markers gradually increased ( Figure 2 ). After RECIST PD diagnosis, his tumor markers gradually decreased, and the mediastinal LN shrank ( Figure 2 ).
case_images: Second late-phase pseudo-progression at 3.5-years of nivolumab. At 3.5-years of nivolumab, tumor markers again increased and mediastinal LN was swollen (short axis 5 27 mm, 2nd pseudo-progression; +440%). PET-CT scan revealed a high-level uptake of the mediastinal LN. LN specimens obtained by EBUS-TBNA revealed TTF-1 positive tumor cells and lymphocytes. PD-L1 TPS was 10%.
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case_images: PD-L1 stain showed the tumor proportion score (TPS) as 10% immunohistochemically (22C3,  Figure 3 ).
case_images: Third late-phase pseudo-progression at 6-years of nivolumab. After biopsy, the lymph node shrunk again. Third pseudo-progression was observed after 6-years of nivolumab. Pseudo-progression repeated three-times in this patient during nivolumab administration (short axis 18 30 mm, 3rd pseudo-progression; +66.7%).
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case_images: Although the patient experienced a total of three pseudo-progressions ( Figure 4 ), he has been receiving nivolumab monotherapy for 8.5 years with no symptoms and PS 0.