The role of local expression of hormone receptors in the genesis of idiopathic tracheal stenosis

Background: Tracheal stenosis in adults is usually the result of mechanical injuries either from direct trauma, tracheotomy or intubation. Idiopathic stenosis in the cricotracheal section is a rare condition and occurs almost exclusively in females. Therefore, an influence of the female sexual hormones estrogen and progesterone has been assumed previously. Methods: Tracheal specimens of 27 patients who received tracheal resection for either idiopathic tracheal stenosis (ITS) (n=11) or posttraumatic tracheal stenosis (PTTS) (n=16) between 2008 and 2019 in our surgical department were included and retrospectively analyzed. Immunohistochemical staining of tracheal specimens concerning the hormone receptor status of progesterone and estrogen was performed. Results: While post-tracheotomy stenosis occurred in males (n=6) as well as in females (n=10), none of the patients with idiopathic stenosis were males. All of the idiopathic stenosis (n=11; 100%) showed a strong expression of the estrogen receptors (ERs) in the fibroblasts and expression of progesterone receptors (PRs) in fibroblasts in 8 of 11 (72.7%). In the post-tracheotomy patients, only 3/16 (18.8%) showed slight staining of PRs and 6/16 (37.5%) of ERs. Of those, only one male patient presented with expression of ERs and PRs and another male patient presented with isolated PRs. Oral intake of hormone compounds was seen in 11/27 (40.7%) patients: 7/11 (63.6%) in the ITS group and 4/16 (25%) in the PTTS (noteworthy that the PTTS group included 6 male patients). Conclusions: Although the number of patients is small, our results show that the expression of female sexual hormone receptors in the fibroblasts of the trachea is a persistent finding in ITS. Surgery provided good results with a favorable long-term outcome without recurrence of stenosis for ITS and PTTS. Further investigation with a special focus on hormones is needed to assist in the prevention of this rare disease.