A 28-YEAR-OLD HISPANIC WOMAN PREsented with a 2-month history of progressive nasal obstruction, muffled voice, throat fullness, and an inability to sleep while supine because of obstructive symptoms. She had also lost 9 kg as a result of progressive dysphagia to solids. She denied having pain, fever, shortness of breath at rest, or chronic cough. She did not use tobacco or alcohol and had not been exposed to occupational toxins. Physical examination revealed a soft tissue mass filling the entire oropharynx, with anterior displacement of the uvula and soft palate. On digital examination, the mass appeared to be distinct from the soft palate. Fiberoptic laryngoscopy revealed a soft tissue mass extending from the left maxillary sinus ostium, tracking posteriorly toward the nasopharynx, and extending to the level of the left pyriform sinus base. The vocal cords were easily visualized and mobile, and the results of the rest of the physical examination were normal. Computed tomography of the neck and sinuses (Figures 1, 2, and 3) showed a low attenuation mass with subtle peripheral rim enhancement extending from the left maxillary sinus to the epiglottis. There was complete opacification of the left maxillary sinus, with extension of sinus disease into the nasopharynx. Magnetic resonance imaging of the orbit, face, and neck, with and without gadolinium enhancement (Figure 4), demonstrated a 3.2 7.8 4.0-cm pharyngeal mass that was isointense on T1-weighted images and of high signal intensity on T2-weighted images. The mass was heterogeneous, with predominant peripheral enhancement. The patient underwent successful complete resection of the mass via a combined endoscopic maxillary antrostomy and transoral approach. What is your diagnosis?