PMC10362299_01
Chest X-ray findings. (A) A giant mass shadow was observed in the left upper lung field at the initial visit. (B) The pulmonary metastatic colonies in the right lung were obviously enlarged when second-line chemotherapy was introduced. F1CDx was performed at this time. (C) The lung metastatic colonies were further enlarged when osimertinib was introduced. (D) A marked anti-tumor response was observed after two months of osimertinib treatment.
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X-ray showed a giant mass shadow in left upper lung field (Fig. 1A), so she was referred to Tokushima University Hospital. Subsequently, the primary tumor grew and invaded the spinal canal, so we treated the patient with palliative irradiation (50 Gy), followed by S-1 (50 mg twice daily for 14 consecutive days followed by 7 days of no treatment) as second-line chemotherapy, as the pulmonary metastases had obviously grown (Fig. 1B). Although we administered S-1 for three cycles, the metastatic nodules in her right lower lung field grew (Fig. 1C). She showed a favorable anti-tumor response here (partial response according to the Response Evaluation Criteria in Solid Tumors [RECIST] v1.1) (Figs. 1D, and Fig. 3), and the response has continued for six months since the administration of osimertinib.
Pathological findings. (A) Hematoxylin-Eosin staining revealed that relatively enlarged malignant cells focally proliferated. Yellow arrows indicate mitotic figures. Black arrows indicate the lymphocytes infiltration. (B) The tumor cells were positive for TTF-1 (B) but negative for p40 (C). (D) PD-L1 22C3 PharmDx revealed that the tumor cells were strong positive for PD-L1 (tumor proportion score: 95%). Bars indicate 100 mum. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
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The tumor cells were positive for thyroid transcription factor -1 (TTF-1) but not for p40 (Fig. 2B and C). The immunohistochemical analysis revealed that her tumor cells were positive for programmed cell death-ligand-1 (PD-L1) as determined by PD-L1 22C3 PharmDx (tumor proportion score: 95%) (Fig. 2D).