The importance of biopsies in distinguishing lung adenocarcinoma from remote breast cancer: A case report

Lung adenocarcinomas can grow in a manner very similar to pulmonary metastases. In patients with a history of breast cancer, these lung adenocarcinomas can be mistaken for metastases as a breast cancer recurrence. If the pathology of a pulmonary lesion is not determined using a biopsy through immunohistochemical analysis, inappropriate treatment may be prescribed to the patient. We report the case of a 76-year-old woman with a prior remote history of breast cancer, who developed lung adenocarcinoma initially presumed to be pulmonary metastases. Treatment targeted towards breast cancer had been planned when the patient decided to postpone the treatment until a biopsy had been completed. The biopsy revealed a primary lung adenocarcinoma for which treatment was then prescribed accordingly.