Inflammatory pseudotumor of the trachea.

"Inflammatory pseudotumor" is a broad descriptive term used to describe a localized collection of inflammatory and fibroblastic cells. It is an uncommon lesion that can mimic a tumor when it is located intraluminally in the trachea or bronchi. Because an inflammatory pseudotumor has an abundance of polyclonal plasma cells, its etiology (postinflammatory vs immunologic) is still being debated.