Bronchial salivary gland-type mucinous adenocarcinoma harboring a GNAS mutation: a novel lung cancer entity? A case report

We report a case of a 65-year-old man with a 1.0-cm mass in the left main bronchus, exhibiting overlapping morphological, immunohistochemical, and genetic features with both pancreatic intraductal papillary mucinous neoplasm (IPMN) with associated invasive carcinoma and salivary gland IPMN. Based on its close proximity to the bronchial submucosal glands and the expression of NKX3.1 (an established immunohistochemical marker for mucinous acinar cells of the minor salivary glands), we propose that the tumor originates from the mucinous acinar cells of the bronchial salivary gland. Therefore, we suggest naming it bronchial salivary gland-type mucinous adenocarcinoma. Interestingly, a GNAS mutation, known as a highly specific marker for pancreatic IPMN, was detected by next-generation sequencing in our case. We believe that this tumor may represent a novel lung cancer entity.