Dual primary cancers of skin cancer and lung cancer: a case report.

[UNLABELLED] This case report details a 76-year-old female patient presenting with a back mass and lung lesions. After a series of examinations and surgeries, she was diagnosed with dual primary cancers of skin (poorly differentiated squamous cell carcinoma) and lung (acinar adenocarcinoma and solid adenocarcinoma). The article discusses the diagnostic criteria, treatment options, and the importance of long - term follow - up for multiple primary cancers, highlighting the increasing incidence trend and relevant influencing factors.Given that cancer patients have a high risk of developing a second primary tumor, even if the primary tumor has undergone radical surgery, long - term and close follow - up is still necessary. During the follow - up process, attention should not only be paid to the changes in the organ where the primary tumor is located, but also to the abnormalities in other organs. Comparing pathological sections and combining molecular biological methods such as immunohistochemistry can help accurately identify the second primary cancer. For the treatment of the second primary cancer, the same principles as those for the first primary cancer should be followed, with radical surgical resection being the first choice. To improve the treatment effect, it is necessary to regularly monitor patients after the treatment of the first primary cancer, so as to detect the second primary cancer at an early stage, strive for early treatment opportunities, and thus improve the overall treatment outcome.

[SUPPLEMENTARY INFORMATION] The online version contains supplementary material available at 10.1186/s13019-025-03793-0.