Multiple primary lung cancer (MPLC) refers to patients with two or more primary lesions of lung cancer. It can be divided into synchronous MPLC (sMPLC) and metachronous MPLC (mMPLC) based on the timing of occurrence. In recent years, the detection rate of MPLC has gradually increased. However, considerable controversy exists in distinguishing MPLC from intrapulmonary metastasis (IM), especially when the histopathological types are identical. Given the significant differences in treatment strategies and prognosis in clinical practice currently, accurate diagnosis of MPLC is crucial for personalized precision therapy. Molecular genetics and sequencing technologies offer effective strategies for assessing the clonal origin of tumors. There have been reports of coexisting mutations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) fusion genes in non-small cell lung cancer, but case of EGFR mutation following an ALK mutation has not been mentioned. This article accurately diagnoses and retrospectively analyzes the clinical data of a case of ALK mutant adenocarcinoma in a male patient who developed an EGFR mutation with multiple metastases four years after surgery, and reviews the relevant literature. This paper aims to deepen the understanding of mMPLC and provide clinical references for the diagnosis and treatment of such patients.
.