case_images: PMC10838107_01
case_images: Positron emission tomography computed tomography (PET-CT) scan of baseline. (A) PET-CT revealed the clinical stage of this patient is IVB (cT4N3M1c); (B) A space-occupying lesion in the right superior lung lobe and a metastasis lesion in the pericardium; (C) Metastasis lesions in the left adrenal gland and a thoracic vertebra; (D) multiple metastasis lesions in the skeletons.
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case_images: Positron emission tomography-computed tomography (PET-CT) revealed a space-occupying lesion in the right upper lobe of the lung, along with multiple masses in the pericardium, various skeletal sites (including bilateral ribs, thoracic and lumbar vertebrae, iliac bone, and bilateral femoral bones), right latissimus dorsi muscle, and left adrenal gland (Figure 1).
case_images: H&E, typical image of pathology. Immunohistochemical staining images of pan cytokeratin (PCK) (+), cytokeratin 7 (CK7) (+), cytokeratin 5/6 (CK5/6) (+) and Ki67 (60%).
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case_images: Morphologically, the appearance was consistent with poorly differentiated carcinoma, with adenocarcinoma features (Figure 2).
case_images: Illustration of EML4-MET fusion. (A) Integrative Genomics Viewer (IGV) shows the break point of EML4-MET fusion based on NGS analysis; (B) The EML4-MET fusion had breakpoints in the EML4 intron 13 and MET intron 14, which conferred the fusion of EML4 exon 13 to MET exon 15.
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case_images: Further, a blood sample was collected for next-generation sequencing (NGS)-based molecular profiling of circulating tumor DNA (ctDNA) (conducted by OrigiMed, Shanghai, China), which identified a novel EML4-MET fusion, comprising exons 1 to 13 of EML4 and exons 15 to 21 of MET (including the complete MET kinase domain) (Figure 3).
case_images: Tumor response to savolitinib treatment. The CT scan shows that some lesions (red arrow) in the baseline and 1 and 3 months after savolitinib. The red arrows indicate locations that correspond to tumor foci.
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case_images: A subsequent CT scan revealed significantly increased right pleural and pericardial effusions, as well as a small left pleural effusion, indicating progressive disease (PD) (Figure 4).