Case Report: Aumolertinib response as a diagnostic clue for intrapulmonary metastases.

Lung adenocarcinoma, which is most common in non-smokers and women, rarely presents with diffuse pulmonary nodules. Distinguishing monoclonal intrapulmonary metastases (IPM) from polyclonal multiple primary lung cancers (MPLC) is essential for treatment planning. Although next-generation sequencing (NGS) accurately determines clonal origin, it can be costly and time-consuming. We report a lung adenocarcinoma case with diffuse solid nodules in a 52-year-old non-smoking female. Empirical treatment with aumolertinib resulted in rapid, homogeneous regression of lesions within four weeks, supporting an IPM diagnosis. This uniform treatment response suggests a practical diagnostic indicator for monoclonal disease when NGS is unavailable, facilitating concurrent diagnosis and therapy.