A 41-year-old non-smoking Chinese female was admitted to our hospital...She was diagnosed with lung adenocarcinoma...Coexistence of somatic L858RI and V843I mutations in EGFR exon 21 was detected in both blood and pleural fluid...the patient began combination therapy with osimertinib (80 mg daily) and bevacizumab (500 mg daily), leading to disease stabilisation until June 2020. Of note, during treatment, the patient achieved sustained control of metastatic brain and bone lesions, and no adverse event was observed.