Primary low-grade salivary gland-type intraductal carcinoma of the lung with CCDC6::RET fusion: Case presentation and literature review

Salivary gland-type intraductal carcinoma (IC) is a rare type of low-grade salivary gland neoplasm. Given that the clinical and imaging features of primary lung IC are nonspecific, the diagnosis requires pathologic analysis. We report a 63-year-old woman with primary low-grade salivary gland-type IC of the lung, characterized by an origin from the bronchus submucosa, an intraductal or intracavity growth of ductal epithelium, an absence of interstitial infiltration, and harboring an RET::CCDC6 fusion. Through case presentation and a literature review, we discuss the differential diagnosis and clinical management of salivary gland-type IC of the lung. Molecular testing is not necessary for histologic subtyping but can aid in the differential diagnosis of IC.