<p>Obstructive Sleep Apnea (OSA) is a common sleep disorder characterized by recurrent episodes of upper airway obstruction during sleep. As most cases are multifactorial, a multidisciplinary approach and thorough anatomic evaluation are essential to rule out structural abnormalities that may contribute to airway collapse. Inflammatory pseudotumors (IPT) of the retropharyngeal space are rare benign lesions that can progressively cause significant upper airway obstruction if left untreated. We present the case of a 61-year-old man with a supraglottic retropharyngeal IPT diagnosed sixteen years prior, which remained untreated until it led to sever OSA and failure of continuous positive airway pressure (CPAP) therapy. Flexible nasoendoscopy and CT imaging confirmed near complete upper airway obstruction caused by progressive enlargement of the mass. The patient underwent successful transoral endoscopic removal of the mass after ensuring the airway with a temporary tracheostomy. Postoperative recovery was uneventful, and follow-up polysomnography demonstrated significant improvement in OSA parameters. This case highlights the importance of comprehensive, multidisciplinary evaluation in patients with OSA, including anatomical assessment of the upper airway. Rare structural lesions, such as retropharyngeal IPTs, should be considered in the differential diagnosis. Transoral endoscopic surgery can provide a safe and effective treatment option with favorable functional outcomes.</p>