ERBB2 Exon 20 Mutation-Guided Trastuzumab Deruxtecan Therapy in Metastatic Lung Adenocarcinoma with Low HER2 Expression: A Case Report
: HER2 mutations are uncommon in lung adenocarcinoma, and treatment options become limited after failure of standard systemic therapies. We report a 69-year-old woman with metastatic lung adenocarcinoma involving multiple lymph nodes, bone, and the left adrenal gland. Histopathological and immunohistochemical examinati...