Fig. 1

diagnosis (cT2N3M1b) and tumor response in the first-, second-, third-, and fourth-line treatments. The first-line treatment (erlotinib plus radiotherapy, December 2014) (a/b) CT scans showed a mass (3.8 cm* 3.3 cm) on the left upper lobe on December 29, 2014; PET/CT found the mass and multiple enlarged lymph nodes at bilateral neck, clavicle, left pulmonary portal, mediastinum, the 4th thoracic vertebra and left acetabulum, and showed left sciatic metastasis; Whole-body bone scintigraphy showed abnormal metabolism of the anterior superior iliac spine; (c) Immunohistochemistry staining showed high expression of CK7, TTF-1 and Ki67. Original magnification × 200. d The second-line treatment (local radiotherapy, March 2016). Thoracic CT and Whole-body bone scintigraphy showed the lung mass and bone metastases were stable, but bilateral neck and right supraclavicular lymph nodes were slightly larger than before. e The third-line treatment (osimertinib plus local radiotherapy, April 2017). Whole-body bone scintigraphy found more bone metastases. Thoracic CT showed the lung mass was stable but cervical lymph nodes reappeared. f The fourth-line treatment (apatinib, August 2017). Thoracic CT showed the mass and nodules (especially lesion in the upper lobe of the left lung) were bigger. Lumbar MRI showed a mass of 5.5 cm *2.9 cm in the left appendage area of the 1st and 2nd lumbar