Primary tracheal adenoid cystic carcinoma: A case report and analysis of the tumor immune microenvironment using single cell RNA sequencing

Background: Tracheal adenoid cystic carcinoma (ACC) is a slow growing yet aggressive malignancy with high rates of local recurrence as well as distant metastasis. Tracheal ACC exhibit a low mutation burden along with high mutational diversity, and generally do not respond well to chemotherapeutics. Methods: We present a rare case of primary tracheal ACC initially presenting with nonspecific cervicalgia and globus sensation that was ultimately treated with tracheal resection followed by chemoradiation. Immune profiling of intratumoral T-cell receptor (TCR) repertoire was subsequently performed using single cell RNA sequencing (scRNAseq). Results: We describe a rare case of primary tracheal adenoid cystic carcinoma highlighting several management principles as well as providing new insights into intratumor T cell populations. Conclusions: Primary tracheal ACC is most commonly treated with surgical resection followed by adjuvant therapy. Further characterization of the tumor immune microenvironment is necessary to better understand ACC disease biology and to identify potential therapeutic targets.