case_images: PMC9468776_01
case_images: (A, B) Computed tomography (CT) scan at diagnosis showed a lung mass in the right lower lobe and mediastinum; (C, D) positron emission tomography/computed tomography (PET/CT) scan at diagnosis showed high fluorodeoxyglucose avidity.
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case_images: Chest computed tomography (CT) and positron emission tomography/computed tomography (PET/CT) showed the right lower lobe lung cancer (35 mmx60 mm) (SUVmax = 14.1) with the right hilar and mediastinal lymph node metastasis ( Figures 1A  -  2D ).
case_images: (A) Computed tomography (CT) scan after chemoradiation showed partial response; (B-D) CT scan showed stable disease during osimertinib treatment.
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case_images: Chest computed tomography (CT) and positron emission tomography/computed tomography (PET/CT) showed the right lower lobe lung cancer (35 mmx60 mm) (SUVmax = 14.1) with the right hilar and mediastinal lymph node metastasis ( Figures 1A  -  2D ). After chemoradiation, reexamination CT showed partial response ( Figure 2A ). During osimertinib treatment, the therapeutic effect evaluated by CT was always stable disease (SD) ( Figures 2B-D ).
case_images: (A, B) Computed tomography (CT) scan after 11.5 months of osimertinib therapy showed enlarged primary mass; (C) hematoxylin and eosin (H&E) stain of the mediastinal biopsy tissue sample demonstrating extensive necrosis without tumor cells; (D, E) PET/CT scan after 11.5 months of osimertinib therapy showed no fluorodeoxyglucose avidity; (F) CT scan after 18.5 months of osimertinib treatment showed no relapse or metastasis.
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case_images: After 11.5 months of osimertinib treatment, he reviewed the chest enhanced CT showing the mass enlarged, which was inhomogeneous reinforcement ( Figures 3A, B ). He underwent fiber bronchoscopy, and no tumor cells were detected by the aspiration cytology of the mediastinal lumps; the biopsy pathology showed extensive necrosis without tumor cells ( Figure 3C ). PET/CT showed no high fluorodeoxyglucose avidity (SUVmax = 3.4) to avoid inaccurate puncture due to tumor heterogeneity ( Figures 3D, E ). Now, the patient has continued on osimertinib for 7 months without relapse or metastasis ( Figure 3F ).
case_images: Timeline of the interventions and outcomes.
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case_images: The overall course of treatment is shown in  Figure 4 , and the compliance of this patient was quite high.