An informative discussion with Dr. Buttner on the significance of newly acquired genetic insights into pulmonary invasive mucinous adenocarcinoma (IMA). In the latest WHO classification, IMA is defined as a primary lung adenocarcinoma with tumor cells showing goblet cell- or columnar cell-morphology with abundant intracytoplasmic mucin. Due to its distinctive clinical features, i.e., peripheral location and a high frequency of multifocal, multilobular, and bilateral occurrence it has been defined as a distinct entity with dismal outcome. Two recent studies, including that of Kim et al. Mod Pathol 35, 202–209 (2022), shed some light on the genetic alterations of IMA and are discussed. Our GDPR privacy policy was updated on August 8, 2022. Visit acast.com/privacy for more information.