Abstract
We herein report a 37-year-old woman with lung adenocarcinoma with brain metastases and an asymptomatic ovarian tumor. Immunohistochemistry and a fluorescent in situ hybridization analysis of the biopsied lung tumor revealed anaplastic lymphoma kinase (ALK) gene rearrangement. Although the origin of the ovarian tumor remained unclear, alectinib administration was initiated, and radiological responses were observed in all lesions, which confirmed that the ovarian tumor was a metastasis from lung cancer. Although differentiating the origin of an ovarian tumor is difficult in lung cancer patients due to the rarity of ovarian metastases, alectinib therapy can replace an invasive biopsy, especially in ALK-rearranged lung cancer patients.