An Endobronchial Cyst with Squamous Metaplasia at the Location of an Airway Stent

Abstract

We report a case of an endobronchial cyst discovered on routine surveillance bronchoscopy 1 year after an endobronchial stent was placed in a 52-year-old woman who underwent a single left-lung transplant. The endobronchial stent was noted to be in proper position in the left mainstem bronchus with green, purulent secretions. At the distal edge of the stent was a pink fleshy mass obstructing 70% of the bronchus. An endobronchial biopsy was preformed and after the first “bite” of the mucosa, the entire mass disappeared and clear fluid was released. The endobronchial biopsy indicated squamous metaplasia. Cultures grew Streptococcus pneumoniae and transbronchial biopsy revealed mild rejection without airway involvement. The patient was treated with intravenous antibiotics and steroids. Repeat bronchoscopy 6 months later showed no recurrence of the mass. We conclude that the endobronchial cyst in this patient may have originated from a pre-existing “extracellular cyst” associated with the development of metaplasia. The metaplastic changes are likely associated with a foreign body reaction from endobronchial stent placement exacerbated by chronic inflammation. A review of the literature on endobronchial lesions is presented.