In addition, the third‐generation EGFR‐TKI osimertinib is reported to be active in the CNS.18, 19, 20 In this retrospective study, the LM disease control of all 19 patients was either improved or stable after switching from gefitinib or erlotinib to osimertinib, regardless of whether the T790M mutation was negative or positive. This evidence concerns the gene EGFR and lymphangioma.